DaveTheGardenGuy

Getting Dirty is Good For You!

    We know that productive garden soil contains between 100 million and 1 billion bacteria per gram (about a teaspoon full).  We also know that many of these bacteria have important roles to play in the Soil Food Web and are to a great degree orchestrated by plants through plant root exudates.  What we don't know is what roles many of the different bacteria play.  We know about a small fraction of them that help with nutrient cycling, disease suppression, and are important to water dynamics in the soil but the greater number by far and their related interaction with other organisms is currently beyond our understanding.  In 2007, Christopher Lowry, a neuroscientist now at the University of Colorado found that certain strains of soil-borne bacteria sharply stimulated the human immune system.  One bacteria, however, Mycobacterium vaccae, has been found to have amazing benefits to us directly.

    Mycobacterium vaccae, a bacteria that is common in soil, has been found to activate a specific group of neurons in our brains that produce serotonin.  Serotonin is found in the brain and the blood and is a very important neurotransmitter which helps regulate a whole host of functions including:

• metabolism
• appetite
• sleep
• aggression
• anger
• mood
• anxiety
• behavioral arousal
• motor activity
• coping responses to stress

    Many antidepressants work by serotonin pathways or serotonergic systems.  Antigens derived from the bacteria, which is non-pathogenic and saprophytic in nature, altered stress-related emotional behavior in mice.  The tests and results of studies in London and Bristol showed that the bacteria caused an increase in serotonin metabolism within the prefrontal cortex.  The conclusions from the 2007 studies included "a novel hypothetical framework for investigating the relationships among immune activation, serotonergic systems, and mental health."  This added to previous work showing "unexpected improvements in quality of life scores" to clinical cancer and inflammatory disorder trials.  Another trial using the soil bacteria to treat psoriasis showed Mycobacterium vaccae "gave long-lasting clinical benefit to most patients, with minimal side effects."

    Related to M. vaccae are two scary bacteria:  M. leprae and M. tuberculosis which cause leprosy and TB.  M. vaccae, named after the cow, however, because it was first isolated from cow manure, is ubiquitous in fertile soil and thrives anywhere soil is enriched with organic matter.  Christopher Lowry said that the effect of M. vaccae is "basically no different from all the SSRIs".  This is exciting:  SSRIs are antidepressants and include medicines such as Prozac, but whereas SSRI's are considered "blunt instruments" by many scientists for treating mood disorders, M. vaccae are selective and specific in their ability to excite certain neurons that produce serotonin and directly impact cognition and mood regulation as well as increase the ability to cope with stress and anxiety.

    In a 2008 article in Psychology Today, Daniel Marano explains that eating antioxidant-rich fruits and vegetables may only be half of a newly evolving story of health and that our society's displacement from the natural world has disrupted a deep and direct connection we have to the soil and it's resident organisms.  Indeed, the sharp rise in chronic asthma, inflammatory bowel disease, and other inflammatory, allergic, and immune disorders has resulted in "The Hygiene Hypothesis".  The bottom line is that we as a society have gotten too clean and the recent obsession with sanitation and anti-microbial products has caught up to us.  It's clear that we are a part of the Soil Food Web and removing us from the soil is to our detriment!

    Not only does M. vaccae promote the generation of serotonin in our brains, but also norepinephrine.
Perhaps more important, it induces the neurogenesis, or creation, of more neurons that produce these two amazing  compounds in our brains.  Norepinephrine is just as important as serotonin and affects the amygdala part of the brain where attention responses are controlled, including the "fight-or-flight response and related heart rate, glucose release, and blood pressure responses.  Norepinephrine plays a large role in attention and focus and may be used for indications of attention-deficit/hyperactivity disorder, depression, and hypotension.

    Similar to the striking rise in allergic and inflammatory disorders, the rise in ADHD and Depression and the related increase in the use (and abuse) of drugs such as the psychostimulants Ritalin or Concerta as well as tricyclic antidepressants or newer SNRI's such as Effexor and Cymbalta point towards a modern society who's young kids do not get to play in the soil enough and one who has abused the use of antibiotics.  It would seem that exposing ourselves and especially our children to the soil in the garden could be a good thing indeed.  The Hygiene Hypothesis page in Wikipedia now has 39 references as well as plenty of supporting articles for further reading and external links.  It "has become an important theoretical framework for the study of allergic disorders" and both their increase since industrialization as well as their higher incidence in more developed countries lends credence to the theory which was first given a scientific background by David Strachan in 1989 and later made popular in the 2005 book by Richard Louv called "Last Child in the Woods: Saving Our Children from Nature-Deficit Disorder."  This is now a movement called No Child Left Inside and a Federal bill introduced to the House of Representatives on April 22, 2009, Earth Day.  The bill is currently languishing in a subcommittee on early childhood education due to opposition from a conservative american "think tank" called The Heritage Foundation.

    It is now clear that exposure to bacteria, and especially during neo-natal development helps to adequately develop regulatory T cells.  In 2007, Keven Becker of the Gene Expression and Genomics Unit at the National Institute on Aging wrote an article that supports a link to Autism, also on the rise, to the hygiene hypothesis and shows etiological links between autism, asthma, and inflammation disorders.  He hypothesizes that "immune pathways altered by hygiene practices in western society may effect brain structure or function contributing to the development of autism."

    More recently, Dorothy Mathews and Susan Jenks of the Sage Colleges in New York tested live mice by feeding them live M. vaccae and found that they could "navigate a maze twice as fast and act with less demonstrated anxiety behaviors as control mice".  Mathews said in a May 25 2010 Science Daily article that "learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks."  This is a pretty good reason to promote school gardens!

    So what then, do all these medical maladies have to do with gardening, horticulture, and landscaping?... the point here is that we as organisms co-evolved on this planet along with and as a part of the soil ecology over millions of years.  Over the past 100 years or so we have become increasingly detached from the soil that supports us and our efforts to further cut us off from bacteria and microbes by the use of antibiotics and antibacterial products has led to increases in diseases and disorders.  It's time we realize the health benefits of our natural connection to the Web of life and rejoice in the practice of getting dirty.  The next time you breath in the steamy aroma of fresh turned earth, compost, and manure, think of all the wonderful biology making it's way into your personal ecosystem.  Contemplate the increased biodiversity you now harbor and be glad.  While there are still valid concerns over other bacteria such as certain strains of Escherichia coli, for the most part, the little soil that sticks on the fresh veggies you eat may actually be covered in organisms that are very good for you.  -Yet another great reason to grow your own food and if you don't have one, start a garden today!

Great Gobs of Glomalin!

Now we've all heard about how organic material breaks down into humus.  Humus is the not-so-secret component of "Black Gold"... that earthy well composted organic material that binds soil particulates into aggregates, makes gardeners proud and teary eyed to behold,  and feeds our precious soil food web.  Humus is broken down into two distinct kinds: active humus and stable humus.  Many fertilizers contain a mined humate called Leonardite, the result of thousands of years of the decomposition of ancient freshwater marshes.  For the longest time, humic acids were thought to be the main carbon constituent of soils.  Now, after breakthrough research by Sara Wright in 1996 and further study by her and others, what might be the soil's most important component has been identified.

 Most people have now also heard about Mycorrhizal fungi -fungi that extend and improve plant root's abilities to breakdown, make available, transport, and absorb many minerals and nutrients that would not otherwise be available to the plant were it not for this symbiotic relationship. Once the spores germinate, these fungi can only survive about three days before they must become associated with plant roots or they perish.  Many organic fertilizers contain inoculants of these amazing organisms and their benefits can be dramatic. They are broken down into two groups: Endomycorrhizae and Ectomycorrhizae.  Endomycorrhizae, as the name implies, grow and can produce spores inside the roots of plants and Ectomycorrhizae, which coat the outside of the roots of some plants.

It has also been known that the soil food web is to a large part orchestrated by plants.  This is done through plant root exudates, the study of which is still in it's infancy and our understanding is, and may remain, very limited.  When you consider the importance of soil bacteria, realize that there are an estimated 60,000 species, most of them having not yet been named, studied, or their role understood, and then think of the growing list of plant root exudates that help orchestrate their behavior, you start to appreciate the intricate web we are delving into.  This is a good moment to feel awed at the complexity of an ecology we so often take for granted.  Just as it was amazing for us to realize that the overwhelming  majority of plant tissue is not derived from the soil, but from the air ( CO2) and water (H2O), it is likewise amazing to realize that a large portion of the hydrocarbons produced by plants through photosynthesis are not held in the plants, but exuded through their roots into the soil food web! The area around the roots where all this action takes place is called the rhizosphere.  It's not so surprising then, to think that the endomycorrhizae fungi might likewise also have exudates.

What if I told you that there was a substance in the soil... a substance that was produced by certain fungi in symbiotic relationships with plants... that hold one of the main answers to our planet's health and is able to combat global warming?  As Landscapers and Gardeners we're in a position to both appreciate and play a big part in increasing the amount of glomalin in our soils.  Amazingly, this material  makes up a whopping 27% of soil carbon!  Depending on heat and moisture, glomalin can last from seven to twenty-four years.  Many soil microbes only last for 20 minutes. fungal hyphae may last from days to weeks.  The durability and longevity of glomalin makes it very important for soil health and as a carbon sink.  As a glycoprotein, carbon is stored in both it's sugar component and it's protein component, making it 30-40% carbon, up to 24 times as heavy as humic acids, and soils can contain four times as much glomalin as humates!  It provides more nitrogen and carbon to the soil than do hyphae or other soil microbes and can be found in quantities of over 100 mg/g in some soils.  It's durability is also the reason it took so long to identify it.  To find glomalin, you must put a soil sample in a bath of citrate and then heat it at 250 F for an hour!

Glomalin is named after the order of fungi that produce it: Glomales.  This Arbuscular mycorrhizal fungi creates glomalin in order to give rigidity and strength to it's hyphae so as to better bridge gaps between soil particles and to help transport soil solutions.  As the older hyphae outlive their short lifespan, and new hyphae are produced near the root tips, they release the glomalin in the soil.  It's interesting to note that tilling soil greatly reduces the amount of glomalin in soils.  Also interesting is that higher concentrations of CO2 in the air promotes rapid glomalin production.  This may be one of the major (and overlooked!) feedback loops the Earth has to regulate CO2 content in our atmosphere -and yet another reason to be awed and amazed by the abilities of plants!  Between a 3 year study on shrubs and a 6 year study on grasses in San Diego, Wright and scientists from Riverside and Stanford showed that when CO2 levels reached 670ppm (the level we will attain by 2050 given current trends), Glomales hyphae grew three times as long and glomalin production increased 500%.   Wright says that the same increase can come from good soil management techniques.  Longer hyphae can help plants reach and absorb more water, protect soil from erosion, and increase the fertility of soils.  These are all important traits for plants to survive in a warming climate.

Why is this not headline news?!  Here we have a major component of healthy top soil- the precious material that we all depend on for our survival, perhaps a key feedback loop in regulating our planet's CO2 levels, and an element of soil fertility that may prove more important to our future in the long run than the Haber process of fixing ammonium nitrate.  This discovery is fifteen years old and yet when I ask my fellow gardeners and landscapers if they've heard of glomalin, I get raised eye brows and an inquisitive look... This has to change.  This knowledge is precious.  Hats off to Sarah and her team!  I hope you all go out and include glomalin in your discussions regarding soil fertility and carbon sequestration.

(photo by Sara Wright)

Sustainable Pest Management for the Small Veggie Garden

For the small vegetable grower, there is little room for loss to pests.  Still, the old paradigm of striving to achieve a sterile growing environment has passed.  We all now understand that it is far wiser to work within the natural framework -the food webs- to achieve a balanced equilibrium with multiple feedback loops and as diverse a number of players as possible.  The more diversity there is, the more stable the ecosystem will be and the less likely there will be population outbreaks of pests.  This, of course, makes the task many magnitudes of degree more difficult, although perhaps more intriguing.  There are many common rules of thumb, common sense practices and techniques, however, that will provide a degree of simplicity to a very complicated and multi-faceted problem.

Most of the concepts to consider fall under the heading of IPM: Integrated Pest Management.  IPM can become complicated, but in it's essence, it is a system by which you know your crop, you understand the potential for pests for that crop, monitor for those pests, know the pests that arise, and use multiple approaches to to synergistically prohibit their populations from growing past a known threshold, using the least toxic methods first, and monitoring those populations to know when to act, and how aggressively.  This is obviously more difficult than spraying non-selective powerful pesticides on a regular basis -but is vastly safer, healthier, more cost effective, and more sustainable.  Even the most powerful pesticides we have in our arsenal have become useless to some pest populations due to their ability to evolve and develop resistance.  Working with the natural systems instead of against them always wins in the end.

A healthy plant is more resistant to pests and disease.  Just because a plant is growing quickly does not make it healthy.  Quick succulent growth due to aggressive fertilizing with high nitrogen fertilizers is a prime target to many pests, insect and fungus alike.  Using low strength organic fertilizers eliminates the possibility of abiotic damage due to salts and also allows the plant to develop at a lower pace with stronger cell walls and higher concentrations of tannins, alkaloids, and other natural pest deterrents.  Using a balanced, complete fertilizer also helps plants develop their natural barriers to infection.  Using a fertilizer comprised of meals, guanos, and minerals also means the nutrients will be released slower and more evenly because they must be made available by the biological activity in the soil.

A healthy soil will encourage healthy plants as well as encourage beneficial soil micro flora and fauna that can help protect plants from pests.  A healthy population of mycorrhizae fungi can help protect the plants from stress by supplying the plants with micronutrients and water that they may not have been able to get on their own.  Pests are naturally drawn to stressed plants.  Some soil fungi can also kill harmful nematodes and other pathogens.  As a rule, soil that has good structure is better drained and there is a higher percentage of soil pore space with more oxygen.  This is only possible with humus and the regular addition of organic matter.  More oxygen in the soil eliminates the populations of anaerobic organisms that can be detrimental to good plant health.

One basic pest management method is exclusion.  An example could be using a fence.  A basic fence can keep out many larger pests, deer and pets being major players.  Another popular measure would be to employ regular use of "floating" row covers.  These lightweight spun cloths can be placed on hoops to protect growing crops or even laid directly over sown seed beds to protect the seeds and seedlings from birds.  Gophers can be mitigated by using gopher wire or even galvanized steel beds.  Bird netting can be used to drape over crops nearing maturity to protect ripening fruits and berries.  Copper barriers can stop mullusks.

Traps can be deployed.  Gopher traps take time to master, but are very effective.  Snail and slug traps are easy.  Earwigs and sow bugs can also be trapped if they are a problem.  "Trap Plants" -such as an agapanthus or other similarly strap shaped leafy plant can be used to trap snails for collection.  Sticky traps can be used to both catch and to monitor populations of whitefly, thrips, and other small insects.  Pheremone traps can be used for some moth pests as well as yellow jackets (which don't harm plants).  "Tangle foot" and boron based traps can help mitigate ant activity and populations, thus disrupting them from "farming" homoptera insects such as aphids, mealy bugs, and scale.

"Know Thy Pest"

If you understand the lifecycle of the pest in question, you can use less input to have a greater control.  Sometimes, a simple spray of water during a critical moment of the pest's life cycle is enough to dramatically reduce their population and eliminate the need for further action.  Most pests have multiple natural predators.  Knowing the life cycle of the predator can also help you promote their populations.  Being able to identify their eggs, their adult forms, and avoid removing parasitized pests ("mummies") can help keep high populations of beneficial insects around.  Sometimes adjusting the irrigation and moisture level can help reduce pest problems as well.  Examples would be red spider mites, powdery mildew and downy mildew.  Knowing the pest, of course, must follow good observation.  Looking for damage -symptoms, as well as signs- actual pests, is key.  Regular monitoring and being alert is a good habit to develop.  It is also important to know how the pest overwinters -so that cultural measures such as mulching and leaf disposal can be used to reduce secondary infections and overwintering pests.  Sometimes a simple crop rotation can obliterate a pest population.

It is good to have some tools on hand for when a pest problem reaches your threshold of tolerance.  Soaps and oils can be effective methods to knock down pest populations safely and efficiently.  Soaps work by dissolving the waxy cutin layer of the exoskeleton and allowing the pest to die by desiccation.  Oils work by suffocating the pest.  In general, soaps work really well when it's hot and dry.  Oils can be enhanced by using Neem, a natural pesticide from the Neem tree.  Another tool, Diatomaceous Earth, is a fine powder of ancient diatoms that can be used on pests with hard exoskeletons to scratch their cutin layer and allow them to desiccate.

Compost tea that has been "brewed"... oxygenated -contains populations of beneficial organisms that can help protect and to treat many plant pathogens and other ailments along with promoting healthy soil biology. Specific bacteria, such as Bacillus thuringiensis can be deployed to target lepidoptera larvae such as the corn ear worm. Another bacteria, B.subtilis shows great efficacy on a wide range of bacterial and fungal diseases.  These bacteria are so specific in their action that they can be used right up to the day of harvest.  Pyrethrins are also good natural pesticides derived from Chrysanthemums.  Look for formulations that have OMRI listing (Organic Materials Review Institute) on any spray you use in the garden and follow the label directions.  Remember to always strive to use the least toxic methods first.

Using a combination of healthy soil and plants, good cultural techniques, and regular observation can go a long way towards eliminating pest outbreaks. Strategically spot treating at the right time for a targeted pest is the only time spraying should be necessary.   Knowledge is power.  The more you learn about the pests and their natural predators, life cycles, and preferred habitat, the easier it is to manage them with little input. A great resource besides the web is the Master Gardener Help Desk.  If you have a symptom or a sign and want more information, bring in a sample or call the Desk.  

UCCE Master Gardener Desk
1682 Novato Boulevard, Suite 150-B
Novato, CA 94947
(415) 499-4204  Email: HelpDesk@MarinMG.org

Hours: Monday-Friday 9:00 AM-Noon and 1:00-4:00 PM 

 

 

 

Fall & Winter Veggie Garden Considerations

Fall is here and it's time to address the veggie garden.  Fall is, in most locations, the best time to think about re-organizing, planning, and scheduling your upcoming crops.  It is also the best time to get manure and compost into the garden, plant perennial crops, vines, and trees, as well as adding a fresh layer of mulch.  Most gardeners don't get to the dreamy planning stage of gardening until late December when all is dormant, days are short, and the seed catalogs have come... but that's really too late for this winter's crops and even for getting a head-start on next spring.  Below I've put together some ideas for consideration:

Putting the Garden to Rest:

Traditionally, the gardener had two options... let the land go "fallow", or put in a "cover crop".  Here in Marin we've got more options- and for this we're grateful, but we now know that the "fallow" option is not a good one, no matter where you garden.  Leaving soil bare invites erosion and depletes the soil biological diversity and activity.  At the very least, a heavy layer of organic mulch should be applied so the earthworms and the rest of the remaining soil ecology has some food, is protected from temperature extremes, and hopefully, the possibility of either water or wind erosion is reduced as well as reducing any wind-blown weed seeds from germinating.

A better solution would be to use a cover crop.  A "green manure" crop, as they're sometimes referred to, is generally a mix of a legume and a winter grass; the legume helping to add nitrogen and the grass to increase Organic Matter,"OM", in the form of cellulose -hydrocarbons.  The legume would increase nitrogen through a symbiotic relationship with the bacteria Rhizobia that inhabit the roots of the plants and fixes nitrogen from the atmospheric nitrogen found in air within the pore spaces of the soil.  A legume cover crop can add around 80 lbs of nitrogen per acre.  The other concept is that the "rhizosphere" is kept alive... we now know that plants have co-evolved with various ecto- and endo- mycorrhizae fungi that help them breakdown, transport, and uptake nutrients into their roots in exchange for sugar.  These populations of fungi plummet when the living root matrix is removed from the soil ecology.  Keeping a crop in the soil helps maintain increased and balanced populations of beneficial fungi, bacteria, and other soil organisms.  Vetch and Rye is a good combination of a legume and a grasse, as are other blends incorporating clover or beans.  Fava beans are a favorite as they can also be eaten (edamame) and also grow to impressive size which is good for weed suppression and for younger gardeners who are impressed and inspired by the plants.

In the home garden, space and time is usually limited and the three to four weeks that most cover crops take to decompose after being tilled or disked under is too long to wait.  This can be easily remedied by harvesting the cover crop for the compost and putting finished compost back in it's place.  This way, the garden returns to production, the soil ecology maintains good populations, and the compost gets a big burst of nitrogen and organic matter to heat it up.  This makes no sense, of course, if you're dealing with any sizable agriculture, but the typical back yard raised bed and compost systems can benefit from the quick switch.  That having been said, one must really think about other options before devoting precious soil space to a cover crop.  Legumes should be part of a regular crop rotation program anyway, and most crops can provide a ready supply of organic matter for the compost.  In addition, ready-made compost is now  available from local suppliers who are working diligently to reduce the amount of green waste going to the landfill.  Supporting our local resource recovery and composting facilities is important and many now offer certified organic composts at very reasonable prices.

Adding compost to the soil is most important in the fall.  Our winter rains stir up the earthworms and other soil biota and the organic matter is converted into active humus, releasing more nutrients, and helping to build better soil structure for the following season's crops.  Humus is the glue that holds the texture of the soil -sand, silt, and clay- together into soil aggregates and allows for better tilth -increased soil pore space that equates to increased aeration, water infiltration, and water holding capacity.  If budget allows, for the small home garden, adding bulk compost and continuing with productive food crops might make the most sense, keeping the available space alive, active, and productive year-round.

Heat:

Fall and Winter Crops are all about night-time and soil temperatures.  Not much happens when everything goes below 50 degrees.  One can think about the Winter garden as a huge outdoor refrigerator, keeping greens, tubers, and stems fresh for harvesting or overwintering for a head start on spring.  The trick is to get your crops far enough along to be able to harvest throughout the coldest days and then keep the beds warm as long as possible and protect the plants from extreme conditions -prolonged frosts and pounding wind and rain.

Raised Beds help a lot.  By just adding regular helpings of Organic Matter -"OM" and digging, the planting beds will naturally be higher than the paths in between.  Just a few inches may make the difference between frosted and non-frosted plants.  Raised beds can help add much more height and warmth, not to mention a great framework for garden organization, helping to schedule crop rotations, intercropping, succession planting, and companion planting programs.  They also help reduce compaction as they are designed to eliminate the need to walk on the garden beds.  Raised beds also form a good framework on which to apply cold frame "lights" to help protect plants in the worst of conditions.  Here in Marin, there is generally more damage done from inadequate venting of cold frames -they can get really hot even in the winter!, but wax-based pistons can help automate this task and reduce the risk of cooking the plants you are trying to save from frost.  The ideal top day-time temperature in a cold frame is in the 60-65 range... perfect for the plants to harden off and prepare for the cooler nights ahead.

One tool in our toolbox for frost (and pest!) protection is the floating row cover.  These fine spun fabrics can go right over the crops, or be suspended by metal or pvc hoops, wires or poles, to protect most crops from a number of various pests along with protection from frost.  (Think camping in a tent vs. out in the open on bare ground...)  They are fine enough to allow light and water to penetrate, but still offer protection -usually 4-8 degrees difference.  I've also found these especially helpful in mitigating the effects of leaf miners on chard, spinach, and other brassica plants, not to mention birds, raccoons, and even pets.  When things get really cold, shade cloth and burlap tarps an also add layers of protection.  In those dire situations where we dip below freezing, all these measures, along with irrigation, can work synergistically to keep fresh greens on your menu.

Biology equals heat.  As a side note, I've heard of many stories of fresh manure and straw being placed below raised beds to keep them warm as well as chickens being used as a heat source for greenhouses.  Frost protection is an open playing field for the gardener with ingenuity and persistence.  Routing the dryer vent into a greenhouse might make a lot of sense.

Hygene vs. Habitat:

Winter is the traditional time to clean up the garden and eliminate sources of fungal spores and such from reintroducing themselves to next season's growth.  While this makes sense, one has to take the whole Web into consideration and think about how the beneficials will overwinter.  Our biological buddies are out there working at reducing our pest populations naturally and for free.  Eliminating their winter food and habitat will be at our loss the following season.  The old system of stripping the land bare, burning the pile of debris, and starting over in spring has given way to a new paradigm of knowing our pests and their natural predators, and promoting healthy populations of beneficial organisms that, along with proper cultural techniques, keep pest populations in a low, stable population that is below our acceptable threshold but high enough to support the population of beneficials.  With this in mind, for example, it IS important to make sure that rose and peach leaves get removed and composted -to reduce various fungus diseases from completing their life cycle- but it might be good to leave some of the herbs as well as some composite and umbelliferous plants in place to allow for parasitic wasps to have a nectar source.  Be on the lookout for Lacewing eggs, aphid mummies, and other signs of our natural garden helpers.  A healthy and biologically diverse garden ecology will remain healthy while a bare bones sterile environment is a prime candidate for pest explosions in the spring.

While on the topic of pests... our first rains around Halloween also mean the start of our mollusk season.  While this may not be as exciting as the deer or duck season to some hunters, snails and slugs can be easily trapped in citrus rinds, various trap crops, or killed outright with iron phosphate... an ingenious use of an effective bait that is also a fertilizer -and not toxic to pets, kids, or the environment when used as directed.  This is especially true for those acid loving plants that tend to become iron deficient in alkali situations.  Placing a meager bounty on the heads of these one-footed foes can also entice children to scour the garden for spare change.  Again, know thy pest and where they hide.

Mud and Darkness:

As the garden gets closer to the Winter solstice, two elements help keep the gardener away:  The mud and the dark.  Both these problems can be easily solved:  Address the garden paths in the early Fall and add a key tool to the garden tool box:  a head lamp.  Adding a fresh layer of wood chips, rice straw, or some other mulch -with a layer of cardboard or weed fabric if needed/desired, can quickly eliminate the mud -and the reluctance to venture quickly out there to cut greens and herbs.  Likewise, a lightweight headlamp hanging by the door along with your pruners can eliminate the other hinderance to winter gardening and open up a whole new world for those who get home from work after dark and "can't" garden...

The Plants:

I've identified over 25 good candidates to consider for the Fall/Winter garden but I'm going to save this for a follow up Blog.  Those of you in Marin who are interested in this topic and missed my two recent Seminars at Sloat Garden Center can hear more on this subject this Thursday at the Marin Art and Garden Center for the first Continuing Education event of the Marin Mater Gardener Program.  It starts at 6:30.

 

 

 

Gardening in the Space-Time Continuum

 Gardening has evolved.  Today it's not uncommon for people to wait years on a waiting list for an opportunity to get a small plot in a community garden in which to partake in the heady emotions and both psychological and physical benefits that come from a direct connection to our Earth mother along with the priceless feelings of having tasted the contentment that can come from that connection as well as the knowledge that one has been a good land steward here on the planet, connected with the community, and produced healthy  nutritious food for one's self, one's family, and one's friends and neighbors.  These benefits are truly life changing, utterly basic in their ability to fulfill the needs of the human condition, and yet so precious as to be rare on the planet in this post industrial age.

Once one gets a garden plot, where to begin?  How does one maximize these benefits?  The food is surely secondary.  The feelings achieved from digging fresh compost into a plot, the knowledge of increasing the biodiversity, the  tilth, and the humus content of the soil along with all the good negative ions, beneficial bacteria, and insects that one can attract is intoxicating. The new gardening camaraderie of your fellow gardeners is also where it's at in terms of basic feelings of well being and right livelihood.  Luckily, our species has been at this for quite some time, co-evolving alongside our photosynthetic friends, molding them to our liking through breeding and hybridizing programs that stretch back beyond recorded history, and we are now the beneficiaries of this heritage heirloom knowledge.

All the tricks to success, once one gets past acknowledging the soil food web mentality, tend to favor the saving of both space and time.  Moderns science now tells us that the two are one and the same and yet together they make up the fabric of reality as we experience it.  To the gardener of a small plot with a busy schedule, however, space and time can become the limiting factors of how much priceless benefits one can glean from their gardening experience.  Even though it may seem we are going fast, we are no where near the speed of light, and our mass will not be bending the fabric of space-time any time soon.  Below are some simple and yet time-tested strategies for saving both time and space in a small garden plot:

Succession Planting:  This operates like clockwork.  Our climate here in Marin allow us to garden in a prolonged season that can accommodate multiple seedings, setting out of starts on successive dates, and a prolonged harvest.  This is especially true of baby green crops and short lived corps.  Tables that describe the "days to maturity'" or "days to harvest" can be consulted for planning this for the greatest benefit. Seeding every two weeks for most greens is a good start.

Intercropping: Some plants grow fast, some slow.  Some plants take up more space later in their lifespan.  Some plants do better when shaded and protected by other plants.  Growing two crops in one area can greatly increase the productivity of a given plot of soil.  Lettuce and onions along with a quick radish crop are classic examples.  There are many more.

Companion Planting: Some plants can actually benefit others by providing nutrients, attracting beneficial organisms, or repelling unwanted pests.  A good example would be how marigolds inhibit the root knot nematode that affects tomatoes.  Another might be how blooming cilantro (coriander) can attract parasitic wasps that keep aphids in check.

Crop rotation: Traditionally the four square garden rotation of root, fruit, grass, and legumes has proven successful.  Now, rotating plant families is used to help maintain healthy soil ecologies along with balancing carbon and nitrogen levels.

Row Covers: These spun agricultural fabrics can help extend the growing season as well as protect young crops from birds and other pests such as keeping leaf miners from laying eggs on chard plants -or even keeping dogs and cats out of a newly seeded bed.

Sheet Mulching: All the rage in sustainability gardening, the use of recycled cardboard as a weed barrier beneath a layer of mulch can smother perennial weeds and stop the cycle of annual weeds in one season while improving soil organic mater content and increasing earth worm populations. Less time weeding and more space for desired plants just makes good sense.

Cover Crops: Although it's possible to keep a bed in production year-round here, cover crops are far preferable to leaving land fallow.  Soil ecological diversity takes a dive when there's not an active rhizosphere in place.  Blends of grasses and legumes can add nitrogen and organic matter -but rather than turning them under and waiting for them to decompose, it's more efficient to compost them and add ripe compost right away, thus keeping the beds alive and productive with minimal downtime.

Drip irrigation and ET based controllers: Here's the big time saver: automatic irrigation.  If the time a gardener spends irrigating can be spent gardening, much more can be accomplished.  Modern controllers that blend historic averaged evapotranspiration curves with on-site weather data are now affordable and easy to implement, making efficient irrigation possible with little input of our time.  Pressure compensating and self-flushing emitters and related advances in in-line drip tubing makes  getting water where it needs to be when it needs to be there in just the right amounts a realistic possibility.

Head Lamps:  For those of us who have a busy life, juggling jobs and kids, those who need fresh herbs after dark, maintain compost and worm bins after hours, and those who take advantage of our climate to extend the growing season on both ends... modern head lamps can show us the light.  Nocturnal feeders are now exposed, daylight is not a limiting factor, and yes, you are now a bona fide garden geek.

The list goes on, but these strategies will save you both time and space, get you closer to the garden nirvana we all crave, and make you a hero around the community compost pile.  Go forth, live long, and prosper. I know your garden will.  Happy Gardening!

Master Gardener

 Earlier this month I finally handed in my final exam for the  Marin Master Gardener   program and a week later I got my pin, diploma, and bumper sticker.  I had always known I'd go through the program and join the group, but the slowdown in the economy inspired me to go for it sooner (perhaps many years sooner) than I might have, and I'm sure glad that I did.  It's a huge time commitment and the Thursday classes were tough to work my schedule around, but the pay-off has been huge and I've really only touched the surface.

Besides the wonderful group of classmates from the 2010 class, there are over 300 Marin Master Gardeners that I'm slowly being introduced to and, of course, they are all proving to be wonderful Marin Gardeners who are passionate about so many of the same things I am.  I'm getting more involved with the Marin Art and Garden Center, lovingly referred to as "MAGC", the School Gardens, the County Fair, a local therapeutic garden, and a host of other projects.  They also work hand in hand with the MMWD to help our communities save water in their landscapes.  Did you know there is a growing organic demonstration farm at the IVC campus?

The resources the Marin Master Gardeners and the good folks at the UC System provide to our community is truly a vast piece of work.  The  Cooperative Extension  works to get the information of the ANR, the University of California Division of Agriculture and Natural Resources out to the public.  The UCCE has been helping people solve horticultural problems since 1913 when “Extension Agents” supervised “Victory Gardens” during the world wars. The Master Gardener Program was started in King and Pierce counties in Washington State in 1972.  The California Master Gardener Program was started in Sacramento and Riverside Counties in 1980, followed quickly after by Fresno in 1981.  In 2006, it was recognized as a statewide program and included 36 counties and over 3200 certified master gardeners.   The Marin Master Gardener program was started in 1986 and Napa county followed in 1995.   The list of Master Gardener County Websites now totals 45. A detailed historical overview of the Master Gardener Program can be found as a PDF document here.  As of 2006, the certified California Master Gardeners had donated over 1,931,787 hours of volunteer time valued at over 2.09 million dollars.  In 2009, the Marin Master Gardeners donated more than 13,000 hours of volunteer time to community projects.

The specific Core Values and Purpose of the Master Gardener Program are as follows:

The purpose of the UC Master Gardener program (MGP) is to extend research based knowledge and information on home horticulture/pest management issues to the residents of California. There are a set of core values that guide the program. These core values are the criteria for designing and implementing educational activities and measuring educational impacts. These core values are:

a.                  UCCE MGP activities focus on education, not service.

b.                  Activities meet identified clientele issues and needs.

c.                  Master Gardener Volunteers are guides to learning and respect others’ viewpoints andabilities.

d.                  Educational activities are inclusive, not exclusive.

e.                  MGs extend only researched based and technically accurate information.

f.                  UCCE MGPs encourage improved environmental quality and sustainable gardeningpractices.

g.                  MGs emphasize “learn-by-doing” methods.

h.                  MGs teach new skills, validate achievement, and encourage extending to others.

i.                  Activities build community support for UCCE through improved visibility.

Some of the best resources, besides classes, telephone hotlines, plant clinics, fairs, horticulture seminars, and demonstration gardens, are websites full of useful and (fairly) easy to find information.  These websites are open and available to everyone.

The most favored is probably the UC IPM website.  This site is the gateway to a wealth of information from the technical to the simple on best management practices for most horticultural issues.  The California Gardening site is also a big winner, but is primarily an easier directory to the IPM site.

Shortcut links to my favorite spots on the IPM site are:

Pest Notes

Vegetables and Melons

Exotic and Invasive Pests

Pests on Trees and Shrubs

Weed ID Photo Gallery

Natural Enemies Photo Gallery (beneficial insects and other organisms who help!)

 

There are SO many other resources!  A full listing can be found on the CommServ, the ANR Communication Services Web Server.  

Some good ones from the Marin site are:

Oak Mortality Task Force (staying up to date with S.O.D)

Urban Bee Gardens

Marin Master Gardener Plant Selector Tool (water needs, deer, wildlife value, etc.!)

A list of Marin Master Gardener Projects

Any list or description of some of the fantastic resources supplied by the UCCE Master Gardener Organization would not be complete without mentioning The Desk.  Located at 1682 Novato Blvd. in Novato, The Desk is the place to bring samples of plants, pests, and all things horticultural to be identified and problems solved.  The Desk is open from 9 to noon and from 1-4pm Monday through Friday.  OR… you can call at 415-499-4204 or email at HelpDesk@MarinMG.org.

I'm looking forward to a long and rewarding relationship with my growing network of newfound Master Gardener friends, grateful for the opportunities to give back to the community in so many helpful ways, including opportunities to speak, write, and teach, and very proud to be a part of such a fine program.

(-and now that the training program is over, perhaps I can find time to blog once again! ;-)  

-Happy Gardening!  

A New Mindset, Clara's Zany Cup, and OM

 Soil fertility is a complex topic.  It's one that initially seems simple; what could possibly be complicated about dirt and what plants eat?  Especially when one has the background, as I did, coming from a University system that, when I was there in the late 80's, catered to a growing agribusiness mentality and was still entrenched in the mindset of soil testing, charts showing a crop's desired diet, and then adding any elements in short supply in the most economical and directly available way.  Don't get me wrong:  I strongly advise testing your soil.  The problem is that the result of this mindset has been the continued degradation of large tracts of some of our most precious soils using what I would consider to be brutal fertilizers.  While these are not generally used in the home garden, they help make a good point:  We should be feeding our soils and promoting a healthy soil ecology which in turn takes advantage of the soil's natural ability to hold water, nutrients, and increase good tilth through increased humus content and the resulting aggregation of soil particles.  Feeding the plants with fast acting and strong fertilizers can do harm to the soil ecology and over time, reduce the amount of humus, lowering soil fertility.

  Anhydrous ammonia, a vapor that has a whopping 82% nitrogen content, can be injected into the soil to boost the amount of yield you get out of each acre.  Unfortunately, pumping that much nitrogen directly into the soil, although it can be argued that it DOES increase microbial activity after several weeks, has some side effects that are not so great:  The excess nitrogen promotes rapid decomposition of whatever organic matter is in the soil.  The acidity of the soil also plummets and is usually neutralized by adding lime -1.8 times as much as the nitrogen added!  These reduce soil aggregation and results in compacted soils.  

Muriate of Potash, containing up to 60% Potassium also seems like a magic bullet until you realize that it (Potassium chloride) also contains over 47% chloride -salt!  Sodium nitrate, sometimes referred to as Chilean nitrate, is also highly saline.  Salt degrades aggregation.  It also can literally suck water out of plant tissue through osmosis.

So if the "big guns" of conventional fertilizer backfire on us, and the answer instead really lies in building and maintaining humus, the desire to understand what is really going on leads us to the complex web of life in the rhizophere- the magical area surrounding plant roots where interactions of root secretions, microorganisms and mycorhizal fungi- and even interactions with earthworms!  The more I learn about this complex system that is always in flux, the more I realize how little we really understand.  Instead of the conventional mindset of replacing mineral elements, the new mindset is more like micro wildlife management where we have to supply food for all the organisms, keep them protected from excess solar exposure, erosion, drastic swings in moisture content, pH, or temperature extremes.  

Earthworms enjoy a steady food supply.  In agriculture this means reducing or eliminating discing, plowing, and tilling, adding manure, growing cover crops, and keeping as much crop residue on the surface as possible.  In the garden it means not tilling and adding lots of compost and regular layers of mulch.  A happy population of earthworms are said to process 20,000 lbs of top soil per acre per year, increase the water infiltration rate by up to 10 times, and stimulate plant growth (from: ATTRA Sustainable Soil Management by Preston Sullivan)

"... it may be doubted if there are any other animals which have played such an important part in the history of the world as these lowly organized creatures."  -Charles Darwin's take on earthworms after careful study.

While we are now shifting our thoughts from supplying nutrients to plants to feeding the soil organisms, we still need to understand and be aware of the nutrients in play.  There are a few ways to remember the "essential plant nutrients", but the way I learned it was with the slogan:

"C Hopkins cafe mighty good, but Clara's zany cup has many more!"

This is fairly easy to remember and actually maintains the elements in order of decreasing amounts actually used by plants.  Let's break it down:

• C -Carbon, used in photosynthesis to create hydrocarbons, used as part of sugar, starches, and cellulose.
• H -Hydrogen, supplied from water, also used in photosynthesis to form sugars and many other elements
• O -Oxygen, used to generate ATP (energy) through the breakdown of sugars (respiration)
• P -Phosphorus, a component of ATP, used in flower and seed formation, and the control of enzymes
• K -Potassium, used in stomata to regulate water loss
• N -Nitrogen, used in all proteins
• S -Sulphur, used in amino acids and building chloroplasts
• Ca -Calcium, used in translocating nutrients and activating enzymes
• Fe -Iron, used in photosynthesis
• Mg -Magnesium, a part of chlorophyll for photosynthesis and  used in ATP production
• B -Boron, used in sugar transport, cell division and creating enzymes
• Cl -Chlorine, used in osmosis and photosynthesis
• Zn -Zinc, used in DNA transcription
• Cu -Copper, used in photosynthesis, creating lignis for cell walls, and enzymess
• Mn -Manganese, used to create chloroplasts
• Mo -Molybdenum, used in amino acids and enzymes.

(-all paraphrased from wikipedia)

Other elements have gotten on the list since I learned this, such as Silicon (cell walls), Nickel (Nitrogen metabolism), Cobalt(Nitrogen fixation in legumes), Selenium, and Sodium.

The Big Three: N P K; Nitrogen, Phosphorus, and Potassium are considered Macronutrients.  They are reflected as the three numbers on all fertilizer containers, always in that order.  In very broad strokes, fertilizers high in N will cause the plant to grow quickly, putting on vegetative growth.  Fertilizers high in Phosphorus will help promote flowers and roots.  Fertilizers high in Potassium help with reducing diseases and  improving fruit production.

A rule of thumb is that fertilizers higher than a value of 10 in any of the N P K designations is most likely NOT an organic fertilizer.  There are a few exceptions where you see a 12 or a 15, but nothing much higher.  Inorganic fertilizers are usually in a concentrated form and are more readily available to plants, but they are also leeched out of the root zone quickly.  According to the Cooperative State Research, Education and Extension Service, USDA, organic fertilizers "have many advantages".  Soil crusting is reduced, water movement and structure is improved, beneficial microbes are fed, and nutrients are more slowly released over time.  Some possible problems with Inorganic fertilizers are that it's possible to apply too much at once.  Problems with Organic fertilizers noted are related to the possibility of putting on too much non-composted manure and the possible introduction of weed seeds. The real problem with organic fertilizer is that they are generally, per pound of nutrient, more expensive.

"OOOOOOMMMMMM"  Organic Matter:  Compost Compost Compost!  Mulch Mulch Mulch!

Organic matter can come in bulk from regular mulching, or it can be added with compost, composted manures, or specialty organic fertilizers.  A discussion of specialty organic fertilizers and some other soil amendments will be posted on the next blog.  I'll also be talking about fertilizers on the 20th and 27th at local Sloat Garden Centers, Sunday, 10am.

Plants are so cool!

 I have been pondering lately about just how cool plants are -again!  I've written about this in the past but was inspired to revisit the topic on this blog while listening to Glenn Keator, an engaging local author, educator, and plant enthusiast, discuss plant biology with the Marin Master Gardeners.  It dawned on me how fortunate we are to be able to be so intertwined in the lives of so many plants and to be privy to the growing information regarding plants and plant lore.  But it goes deeper than that.  Our day to day relationships with plants as gardeners make us appreciate plants for the beauty they provide and we go about our roles of propagating, pampering, growing, and combining them in artistic and useful ways.  But how often do we contemplate on how much we have in common and how much we owe it to plants for our very existence?

Vascular plants have been here on Earth, indeed, actually involved in the Earth’s evolution, for approximately 440 million years.  There are approximately 350 thousand species of plants.  We as gardeners know that many species are divided up into dozens of cultivars.  The diversity is astounding.  It’s cool to think that this many species have a whole energy system that is somewhat opposite that of ours:  Plants use carbon dioxide to synthesize glucose and give off oxygen as a waste product.  We use oxygen and glucose and give off carbon dioxide as a waste product.  What goes around comes around.

Plants have evolved to accept light at two specific wavelengths.  At these bluer and redder wavelengths, Chlorophyll molecules absorb light in the chloroplasts and we see them in the spectrum of what is not absorbed -green.  Humans have been on the earth about 200 million years -less than half as long as plants.  We are only now figuring out how to capture the energy of sunlight using photovoltaics.  Thank goodness plants have been at it for such a long time.  About 4.4 billion years ago our atmosphere was mostly carbon dioxide and water vapor -and almost no oxygen.  Although the cyanobacteria started producing oxygen about 3.5 billion years ago, when the photosynthesizing plants evolved, the atmosphere changed dramatically and eventually the carbon dioxide got locked up in limestone, shells, and fossil fuels.   This allowed oxygen breathing organisms to evolve.   Now that we’ve been using those fossil fuels for a short while we’ve had to acknowledge  the inconvenient truth that it creates more carbon dioxide in the atmosphere -and global warming.  All the oxygen in the atmosphere also allows the creation of a layer of a special allotrope of oxygen that protects us from much of the suns ultraviolet radiation -the  ozone layer.  Also inconvenient is how our recent use of chlorofluorocarbons has reduced the number of these special  types of oxygen and have allowed a growing amount of genetic damage to living organisms, including us.  As I said, what goes around comes around.

The oxygen put into the atmosphere by plants also reacted with the ammonia from all the early volcanos and formed the nitrogen that now makes up 75% of our atmosphere and is the basic building block of all living tissues and amino acids.  It’s the first number on any  bag of fertilizer.  What’s really amazing is that nitrogen can’t be used directly by plants or animals.  Plants are part of a network though.  Certain bacteria can use nitrogenase enzymes to “fix” ammonium into nitrites, which is then converted by other bacteria into nitrates, finally usable by plants to eventually form proteins, amino acids, and alkaloids.  Some plants have even assimilated the useful nitrogen fixing bacteria into a symbiotic relationship in their roots as in the case with legumes, which makes up a large part of our diet.  Most of our livestock feeds and  pasture forage plants are legumes.  Other plants do this too.  I was surprised to find out that one of my favorite plants, Gunnera, also has a symbiotic relationship with a nitrogen fixing bacteria.  So do Casuarinas, Myricas, and lichens.  The real wonder of nitrogen, however, is when you put four of them in a ring, as in Chlorophyll.

 Glenn brought up a fascinating bit of information to ponder: the similarities between chlorophyll and hemoglobin.  In mammals hemoglobin makes up 97% of red blood cells (dry weight) and is the carrier of oxygen from lungs (or gills) to the rest of the body.  It also is important in neurons and as an antioxidant in kidneys.  In Hemoglobin, an iron ion is surrounded by four nitrogen in a plane, the iron being able to bind with oxygen and translocate it.  In Chlorophyll, it's a magnesium ion that is similarly surrounded by four nitrogens.  These amazing molecules are both produced through the same metabolic pathways and are called Porphyrins;  coordinated with iron: you get the building blocks of our blood, coordinated with magnesium and you get the building blocks of our photosynthetic friends.  Interestingly, but not surprisingly, very similar structures also create bacteriochlorophylls, other photosynthetic pigments that various bacteria use to absorb other wavelengths of sunlight -even sulfur based bacteria.    These amazing similarities between the chemical workhorses of the biological world always inspires a sense of wonder in me, and at the same time a strong sense of oneness, -of connectedness; ourselves being so similar in basic structure to plants and even bacteria.  

Just to leave Nitrogen as a basic building block really doesn’t tell the whole story, though:  Nitrogen, along with a diverse group of bacteria and fungi, are also the basis for decomposition.  Where do you think we’d be without decomposition?  Talk about circular events.   As gardeners we all know the wonders of compost.  And what do we balance in the compost pile?  Moisture, oxygen, nitrogenous material, and carbonaceous material.  And where do you think the carbonaceous material came from?  Plants, of course!  The amazing evolutionary trick that plants pulled off was to develop cell walls.  Animal cells only have a plasma membrane.  Plants get a cell wall.  By combining Hydrogen from water with Carbon from carbon dioxide, again using the amazing chlorophyll in photosynthesis, they can make carbohydrate frameworks: cellulose, by far the most abundant form of living terrestrial biomass.   Plant cell walls consist of several layers of cellulose microfibrils held together with hydrogen bonds that allow high tensile strength and ... wood.  Now where would us landscapers be without wood?  Would our species have evolved at all?

So everything you breath, everything you eat, every hydrocarbon in your body -and every other body, big, small, human or otherwise- is the result of plants.  We may think we are higher on the “food chain”, but perhaps we should think of it more like a tall pyramid with us precariously balanced at the top.  The more solid foundation is made up of plants, bacteria, and minerals.  The “carbon cycle” trumps the “food chain” any day anyhow, and it’s based on plants.  When you think of all the bacteria and enzymes involved, then we’re looking at a Web.  And when you sit out this summer warming yourself in the sun, or find yourself in the hot sun working in a garden, think about all the plants around you using that energy, turning those photons into sugars, breaking the chemical bonds of water, and be jealous.  Be very jealous.  I wish I could do that!  Maybe I’d look good in green too.   Now that we are “building green”,  “voting green”, and “living green”, desperately trying to undue the mess our opposable thumbs and enlarged cerebral cortexes have gotten us into, it’s good to reflect on our fine photosynthetic friends and appreciate them not only for their beauty and usefulness, but for allowing us the ability to be here, use our senses, and appreciate anything in the first place.  It sure is nice to know we are a part of the “green industry” and that our species has now acknowledged the Web and the importance of green.  It's also really nice to know we're so closely related.

"All things share the same breath -the beast, the tree, the man... the air shares it's spirit with all the life it supports"   -Chief Seattle

(chemical structures from Wikipedia- I love the Web!)

Our Most Precious Resource?

I took a class last Thursday with the Marin Master Gardeners and the guest speaker and UC Berkeley Soil Scientist, Steve Andrews.  Steve took us through a wonderful and most entertaining review of soil morphology and additional insights into soil ecology and plant nutrition.  -Truly a a divine experience!  This was a longer version of the class he presented to the Bay Friendly Landscape Professional class I attended last year.  Steve told us that there may be an advanced soil class in the near future.  While at Cal Poly, SLO, I took the soil science classes, and all the topics Steve brought up were reminders of those classes, but that was back in the late 80's and Cal Poly was still somewhat stuck in the old agribusiness mentality of soil as a sterile medium, fertilizers being measured out by the acre and recommendations based on economic returns on investment -without comment about the soil ecology and how it might be affected.  It is so nice to hear a modern soil educator so passionate about our most precious resource, our LIVING soils.

Which is more precious?  Fresh Water, or Soil?... that's a hard one.  We need both.  They are intertwined in the web of life.  One creates the other.  As our species has evolved on Earth, our various civilizations have thrived and crashed primarily based on how we have treated these two resources. Their interaction along with the ecologies they support give rise to the world we hold so dear.  Our understanding of these interactions will be the basis of our survival.  Learning about soil is one of the first steps in learning about life, a big step towards our species making the changes necessary in our practices, and a huge leap towards any individual's concept of where they fit into the web of life - a strong dose of awe that can lead to a better intellectual and even spiritual questioning of how and why we are here.  Perhaps our greatest calling is to be good soil stewards.

A good resource for soil can be found at the WSS, the Web Soil Survey.  This is information provided by the National Cooperative Soil Survey operated by the USDA natural Resources Conservation Service.  Maps and data are available for more than 95% of our nation's counties!  Amazing to type in an address and get so much information: soil complex percentages, elevation, slope, mean annual precipitation, temperature, and frost free period plus depth to water table, etc.  Then you can search for a use and see the results.  

 During our class we got to do a textural ribbon test.  This is done by getting a soil sample damp and pressing it between the thumb and fingers and pushing it through into a ribbon, the length of which determining the relative amounts of sand, silt, and clay.  This exercise, along with rubbing a smaller, wetter sample in the palm of the hand to determine it's grittiness or smoothness can be a good indicator of the soil textural class as depicted on the Soil Pyramid.  The Sand, Silt, and Clay are the "Soil Separates".

 The relative sizes of these are:

Sand: 2mm -.05mm

Silt: .05mm - .002mm

Clay: smaller than .002mm.  (Cant be seen by the unaided human eye!)

"Garden Nirvana!" - the area in the middle of the pyramid (this sounds almost masonic!) where the concentrations of the three soil separates find their sweet spot in the textural class of  LOAM.

Several insights I gleaned is that in most soils, soil pore space, roughly 50% by volume in soil, is filled with air and water, always in flux, and is where the concept of "field capacity" as it relates to water saturation occurs.  This is also where gas exchange occurs and most of soil chemistry.  5% of most soils is comprised of organic matter and humus which, consisting of relatively 80% of that 5%, is the magical "glue" that binds soil into aggregates and peds, the macro structures of soil conglomerates.  The ability of humans to enhance or destroy soil structure is key to the survival of civilization.  These concepts: soil texture, a constant in an anthropocentric time frame, and soil structure, a fragile system that can take thousands of years to create ("pedogenesis") -or destroyed in a very short time frame, form the basis of modern soil classification.

Clay is also where all the action is.  Clay, being .002mm or smaller in size, has both chemical properties an electrical properties.  The negative charge of clay particles allows soils to hold onto cations -important plant nutrients.  The negative clay surface also allows the soil to interact with active nutrient absorption systems that plants (and a plethora of other organisms) have evolved.  The sheer mind boggling expanse of this surface area is hard to comprehend.  Clay particles, which are so small they are not visible to the naked human eye, are comprised of layers, 1:1 or 2:1 of tetrahedral and octahedral layers.  This layering allows an amazing surface area.  Steve pointed out in our class that a single teaspoon of clay can have the relative equivalent surface area of a football field.

Clay can also be the source of life as we know it on this planet.  A.G. Cairns-Smith, in a paper in 1966, postulated that clay was the scaffold upon which life arose.  Clay affords the protection, the repeating layers, the proper distances between those layers, the chemical charge, and the structure to create repeating compounds as well as the affinity for organic compounds and an ability to organize them.  Chemist James Ferris and colleagues at Rensselaer Polytechnic Institute, during research sponsored by NASA, created an experiment where they "induced clays to act as scaffolds in the formation of RNA, the polymer that carries the genetic message enabling protein synthesis".  Harvard University geneticist Jack Szostak, who later mixed clays, RNA nucleotides, and lipids was able to show that the clay not only absorbed the RNA, but quickly formed lipid vesicles. "This spontaneous self-assembly of RNA-containing vesicles, though a long, long way from synthesizing life, is perhaps the closest anyone has come to forming a cell-like entity from scratch". (p.158, Gen-e-sis, Robert M. Hazen, 2005)

The miracle of life may well have evolved in the chemically charged, too-small-to-be-seen, layers of clay.  This concept lends a new perspective to the idea that soil supports life.  Other impressive soil life concepts from the present day include:  a gram of soil contains a population of between 100 million to 3 BILLION bacteria, roughly a million fungi, perhaps miles of mycelium...  and a plethora of virus, anthropods, isopods, etc. -a truly wonderous soil food web with feedback loops and interactions with the macroecology of vertebrates and plants. -too much to go into in this little blog!

We also briefly looked at the Munsell color chart, an expensive and very accurate color system created by Albert H. Munsell and adopted by the USDA for soil research in the 1930's.  It uses Hue, Value, and Chroma to determine the exact color- based on human visual perception.  Soil color can show us clues to mineral concentrations, especially in the B soil horizon where soil elements accumulate due to leaching over time.  As Steve pointed out, the color of soils can also have a legal application in the process of saving our wetlands from overdevelopment.

 Soil as it relates to gardens and gardeners -agriculture- is a huge topic.  I will explore more of this awe inspiring topic and how we fit into the soil web in later blogs.  Fertilizers and their use being the next topic of discussion for the Sloat Garden Center Seminar series (Feb. 20 in Kentfield and Feb 27 in Mill Valley, Miller) and the Marin Garden and Landscape Meet Up group meeting.

That having been said, I can't express enough my main take-away from the class, and almost every gardening class I've ever been involved with:  The magic bullet:  Compost.  Compost adds life, it adds buffers, it adds humus.  Compost can take almost any soil ill and correct it over time, creating a more complex (and thus stable) food web, maintaining better water holding capacity while improving drainage, water infiltration and filtration, soil nutrient availability through chemical and biological actions, as well as a myriad of other benefits including the breakdown of toxins.  As our Co-Horts pointed out, one of the main MMG mantras is " Compost Compost Compost - Mulch Mulch Mulch!"  This is truly the key to improving humus content and soil life.

Steve Andrews also pushed another take-away:  Don't fall into the media-driven trap of regular fertilizing without proper soil testing and taking the plants needs, the season, and climate into account.  This falls right into place alongside the practices of IPM - using the synergistic approach and monitoring before taking action, knowing the biotic and abiotic situation and the possible affects of those actions.

So go forth and spread the good word of Compost, Mulch, and the wonder of Life; in, from, and dependent on -our precious Soil.

Water to Cost More In Marin!

 MMWD just sent out their note regarding the rate increase scheduled for March 1.

The average increase will be graduated so those who use more pay more. For most users, the new tier prices per CCF will look something like this:

• Tier 1:  $3.39   9.8% increase
• Tier 2:  $ 6.78  9.09% increase
• Tier 3:  $13.56 10.61% increase
• Tier 4:  $20.34 11.42% increase (ouch!)

-plus a 4% increase in bi-monthly meter charge depending on the size of your meter.

The notice had good news and bad:

Good News:

Water use dropped by 8.5% last year instead of the projected 5%.

MMWD had some great verbiage in the notice:  "We must... 

• continue to fund water conservation programs, providing rebates and education..."
• retrofit diesel engines to protect the air..."
• replace pipelines and tanks...  ...pumps..."
• participate in a salmon recovery plan for Lagunitas Creek."

Bad News:

... not much, really: just much more expensive to use water for landscaping -especially if you or your clients are in the upper tiers of water use.  Our bills WILL go up.  This is a great incentive to get busy on all the possible ways to save before the higher rates go into effect:

• Rainwater Harvesting
• Greywater
• ET Weather Based Controllers
• High Uniformity Drip and Mini-rotors
• Low Water Use Plants
• More Natives! Less Lawn!
• MULCH, MULCH, MULCH!
• Irrigation tune-ups- fix those leaks!

You could go and complain (written protests must be received no later than the feb 24 public hearing), but with all the incentives this will have to promote the implementation of the above water saving landscape elements as well as allow MMWD to reinstate their conservation and rebate programs, it would seem that we should support the increase as a step in the right direction.

Also, considering that as of the date of this blog, our reservoir storage is a full 19% Less than average this season and rainfall at Lagunitas Lake is only at 13"... much less than the average 22.83, water supplies could get tight.  Lets hope we get a wet spring.  Bring it on, El Nino, we need it.

MMWD: if you're reading this, Please give us back our ET Controller rebate ASAP!