DaveTheGardenGuy

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!

Vine and Cane Pruning of Mostly Deciduous Plants

 Vines hold a special spot in any gardener's pallet.  I love vines because they can add color, fragrance, whimsy, sometimes wild, and/or tropical effects, and many times fruits and berries to eat.  Vines are the first things I think of when thinking about arbors, trellises, or espaliers.  The care of vines, unless one's intention is purely wildlife habitat generation, requires regular pruning.  Most of the pruning of deciduous vines occurs in the winter, but most vines require year round trimming to train them, keep them in bounds, and promote better bloom and fruit/berry production.  There are generally two separate pruning methods for any vine during it's lifetime as it's first more important to establish a good framework, cover an arbor, or establish itself and later to promote fruit and flower, not get out of hand, and sometimes to facilitate harvesting.

Below I'll outline some guidelines for various Vine and Cane plants:

Blueberry:  While really more of a shrub than a vine, I'll touch on these here:  Blueberries fruit on side shoots from previous year's wood.  Prune out older canes to the ground that look overly twiggy or old.  Encourage new canes and prune out lower ones too close to the ground.  The hardest part about blueberries is not the pruning; it's keeping the soil well acidified.  Regular heavy mulching to create humic acid is necessary.

Boysenberry and Blackberry:  These vines produce fruit on laterals that grow from last year's wood.  Traditionally they are grown on three to four horizontal wires, the first one 18" above the ground and the rest 12 inches apart above the lower one.  As this implies, you would first prune out the vines that fruited the previous season to the ground.  I've seen a variation of this where taller canes are allowed to develop and  provide a vertical framework for two to three seasons before being rejuvenated at the ground.  Regardless, all new growth should be trained onto the wires, wrapped once around, and tied with vine tie.  The shorter canes should be used in the center and the longer ones trained out further creating a fan of canes that allows for good sun exposure.  The canes should be tipped just above the uppermost wire or if space allows, weave them up and down between the lower wires.  There is an easier to maintain system that has current vines going one way, the previous year's vines going the other and alternating directions of pruning and fruit production, but this system usually take too much room in a residential setting. 

Clematis:  Clematis is divided into several categories of pruning, but it is good to note that it's desirable to promote more basal shoots in the long run, thus it's good to prune young plants back hard to promote more shoot initiation early.  Clematis bloom on either only the new growth, new canes or shoots that arise along the sides of the canes of the previous season, or on last season's growth, depending on the species.  The evergreen clematis, C. armandii, is in a class of itself, as it's important to maintain the protection of foliage against frost throughout the winter.  For most late-summer/fall blooming deciduous clematis, pruning them back severely -to the first pair of buds out of the ground while dormant is the best rule of thumb.  The new growth is trained (not cut) along the support until bloom.  Early Spring booming clematis usually establish more of a perennial framework, sometimes quite large.  These clematis can benefit from pruning the old flowering shoots or laterals back to two buds above the framework branches.  For some larger clematis it's good to prune back last year's canes by 1/2 to a strong pair of buds.  Some cultivars benefit greatly from a summer pruning to thin the plant right after the first bloom.  This includes the popular 'Nelly Moser'.  Many (most) times clematis get out of hand, producing a huge mound of bare stems.  This can be addressed in three basic ways:  Hedge trim the old growth back to an acceptable form, or rejuvenate them by cutting them back to the first two buds from the ground, or spend the time to train them back to a framework of stronger canes cut back to strong bud pairs.  The latter method is best, but can be prohibitively time consumig.  One word of caution:  it's very hard to tell the difference between living and dead vines in some Clematis and I've learned the hard way that it's best to error on the side of caution and leave questionable structural branches alone.  Just 'cause it looks dead, that clematis might be just fine.

Currents:  Currents can be trained on wires or established as free standing bushes.  They fruit on short shoots arising from last years growth.  Cut back terminal shoots half way.  Laterals get pruned back to two or three buds.  Thinning for sun penetration will promote more and better developed fruit.

Grapes:  Many extensive texts have been written on the various theories and methodologies of grape pruning systems.  Here's the basics:  Grapes will produce way too  much growth and fruit if left alone -and it's hard to harvest an unpruned grape vine!  The desired effect is to establish an organized framework with a series of short laterals that will produce a limited number of new fruiting branches.  It's very important to maintain light exposure to these new fruiting branches for fruit production and fungus avoidance as well as to prepare new laterals for  the upcoming season.  The "Double Guyot" system is the most common where two horizontal laterals are trained on a wire about two feet from the ground, about three ft. long each.  In addition to the thinned vertical fruiting branches that grow from these two laterals, three additional branches grow from the center of the plant to create the next season's two support laterals as well as two to three buds left on the central stem.  The upright fruiting branches are tipped as they reach the top wire and grape clusters are thinned to be at least 6-8" apart.  Each winter, the horizontal is cut out and the three center shoots are spread to create the new laterals and central buds.

Honeysuckle:  Lonicera vines look best when left alone, pruning it only keep it in bounds and allow it to form a cascading blanket of informal blooms.  A hard pruning after bloom can help keep them organized but is not necessary every season.  It can be pruned back hard to it's structural framework for rejuvenation every several years if a neater appearance is desired.

Roses:  Climbing roses can be successfully left to themselves, but do better with some intervention.  It would seem that the more horizontal canes one can establish, the better the floral display as blooms are born on new vertical growth arising from the main framework canes.  Periodic rejuvenation of the older canes can keep older plants robust.  Great benefit can be had by pruning canes back after blooming, either to three buds from the lateral union or better yet, count back to the second leaf of five leaflets below the spent flower and chances are good you may get a second bloom.  Banksia roses can 

Kiwi:  Traditionally, kiwi are trained to a six foot T-bar system, but kiwi also adapt well to an arbor or higher support system above fence height.  Kiwi's are Dioecious, that is, the sexes are present on two different plants and both are necessary for successful fruit production.  The ratio suggested is six females to every one male.   Basically, each plant is pruned to have two main laterals.  From these laterals either canes or spurs are allowed to develop.  I prefer the longer lateral system: Each new shoot is cut back to roughly eight buds... the first six having  the potential ability to set flower and fruit while the last two add to the photosynthetic ability of the plant.  Growth beyond the eighth bud tends to be erratic in nature and potentially dangerous as it's coiling nature can girdle other branches.  These laterals should be spaced roughly two feet apart.  For two to three years, prune the vines back to two buds after the last fruit or flowering site.  After three years, the lateral will die back on it's own or should be replaced by new canes, being pruned out after fruit harvest and allowing two fruiting seasons for each cane.  

Raspberry:  Raspberries are pruned to the ground each season after setting fruit on the previous season's growth.  This can be organized on a single set of wires but is easier done in a "V" system where the previous season's growth is tied to the two side wires and tipped while the current season's new canes shoot up in the center.  Each winter, or better yet, just after fruiting, the older wood is cut at the base and removed and the new vines tied to the wires, allowing space in the center of the "V" for the next season's new growth. (This methodworks for Loganberry as well, although their habit of growth better matches that of a slow boysenberry.)

Wisteria:  All species of Wisteria are usually pruned the same, the only difference being the method to prune a free standing "bonsai" wisteria "tree".  For most applications, Wisteria is trained onto some support structure.  Hopefully this structure is substantial.  Wisteria is a huge, strong vine and care should be taken when young to train them where you want them, taking advantage of their ability and tendency to coil around their supports.  This coiling tendency can backfire, however, as the vines can strangle themselves or each other.  Where possible,  removing situations where vines are girdling each other is a good policy when they're young.  Once the plant has been trained to cover whatever space is available, the subsequent pruning is simple.  Wisterias bloom on short spurs that are created by heading back lateral growth to the first two to three buds.  These booming spurs can become quite dense and create huge displays of blooms.  Summer trimming to promote more lateral growth every two weeks or so can increase blooms the following season, but it's lots of work!  Flowering spurs can be further enhanced if they are arranged in horizontal layers or sprays to show off the pendulous flower clusters.

Pruning Deciduous Fruit Trees

 Please see my previous blog on general pruning cuts, some vocabulary, and quick safety tips.  It's important to start out with the removal of Dead, Diseased, and Damaged wood... remove crossing branches, stubs, suckers, and address water sprouts first.  Also make sure that good sanitation takes place: remove any "mummies" (old dried up fruit) as well as stuck leaves, etc.  The more overwintering diseases and pests that can be cleaned up and removed from the tree's environment, the easier it is to control these issues with cultural controls in the coming season.

When pruning fruit trees, think of where the fruit is borne.  Generally, it is on either new wood, older wood, or on fruiting spurs.  Trees that bear on new wood get pruned hard.  Trees that fruit on older wood less so.  Keep in mind that future fruit will need good air circulation and be able to be reached.  In a home situation, it may be highly desirable to maintain the overall height of the plant much lower.  Take a look at the branches and get a good feeling for where the tree was pruned in the past and where the current year's growth is attached.  Many pruning systems depend on counting the buds from where the current wood starts.  This method also makes it easy to maintain consistency in a tree or orchard.  Remember, though, that the direction of the bud should take precedence over the bud number.

Pruning systems also include such terms as  Open Center, Bush, Central Leader, or Modified Leader.  For the most part, residential settings make the "bush" system the easiest to maintain, as well as to harvest by hand.  This also keeps fruit production lower to the ground and a more "natural" aesthetic in the garden.  The problem with this method is that it takes extra care and more aggressive summer pruning to maintain sun penetration and air circulation, as well as controlling aggressive water sprouts.

Here's a quick chart of some common fruit trees and some notes:

Apple:  Apples fruit on spurs.  These are short stubby branches that arise from older wood and on some cultivars can bear fruit for up to 10 years.  Start by heading back growth to promote new spurs, thinning spurs for air circulation, training for symmetry and strong structure, and removing suckers and water sprouts.  Be sure to tip all terminal shoots as this helps promote more spur formation.  Since apples tend to overproduce, check for weak, narrow crotches or branches over-burdoned with spurs too far from the trunk for the branch to support.  Most apples will self-thin around June, but need additional thinning to avoid breakage.  Narrow crotches can be spread using twine or spreader sticks.

Apricot: Mature apricots fruit on new wood, but heaviest on short interior branches referred to as spurs.  While you want to maintain most of the new wood, it's still good to go through and shape the top of the tree, thinning it to produce symmetrical growth and even strong branch structure.  Because apricots grow quickly and branches can grow too far from the trunk, consider removing far reaching branches or those that have sunk too far towards the ground.  Always trim back to upward facing buds.  Also, it's best to bite the bullet and prune for strong structure when they are young -a few less fruit in the early years is worth it to attain a strong, sturdy structure for the life of the tree. Unlike apple spurs, the short productive branches of apricots will generally only bear heavily for two to three years.  For this reason, apricots are pruned hard to produce abundant new spurs for the coming seasons and older declining spurs are removed.

Cherry:  Cherries also fruit on short spurs that can bear fruit for ten years or more.  Similar, but perhaps more important than with apricots, fruiting cherry trees need aggressive pruning when they are young to promote strong structure.  There are both "sweet" and "sour" varieties, but they both produce weak, narrow crotches.  "Sweet" cherries need more aggressive pruning to keep them from getting too tall.  Once they are mature, they generally only need their tops "organized" as they will naturally create a mass of small top growth that will require thinning for sunlight and air circulation to penetrate to the center of the tree.  Most pruning books designate cherry trees as needing only light to moderate pruning.

Fig:  There are two main groups of figs: "black figs" and "all the rest".  The difference is that black figs will produce fruit on the current year's growth as well as last year's wood while the other fig cultivars will only produce on new year's wood.  The resulting system of heading back "all the rest" figs to the second bud after last year's cut (or annual branch scars) and allowing 4-6 buds on black figs.  Figs are fast, tough trees.  Left to themselves, they can shoot skyward, get top heavy, and ten bend and crack, sometimes rooting where they fall.  That having been said, severe cuts can leave the trees very vulnerable to sun burn.  Older, vigorous growing fig trees respond well to summer tipping -not wholesale topping, but terminal bud removal to produce more stronger structure.  In a residential garden situation, consider whether the tree is to be easily harvested and kept lower, or allowed to become a larger shade tree.  Also keep in mind that the white latexy sap can have a horrible itchy reaction if it gets on your skin.  Figs also tend to send up many suckers from the base... which can be left as a photosynthetic skirt and sun shade for the trunk, or cut clean to the growth rings, the latter being easier to maintain.

Nectarine:  Necarines bear fruit on last year's growth.  Most of the fruit will be in the center of last year's wood.  First, remove all the water sprouts and suckers, then look for branches that bore fruit last year and remove those.  Then select the branches with the most new growth and go about thinning that new growth so that all the branches are about 9" apart from each other, leaving the branches that are the most evenly spaced, symmetrical, and have the widest crotches, tipping them all by about one third their length, cutting back to buds pointing away from the center of the tree.

Peach:  Very similar to Nectarines, fruiting on last year's wood, many fruit tree pruning books show the same diagram/table for both.  Peaches  do best with the Open Center system as sunlight penetration is key to fruit production although an airy Bush system should work fine. Another "heavily" pruned plant, it would appear that peaches like having their fruiting branches slightly more spaced out to a 12" spacing, and more care should be taken not to leave tall, brittle branches that, once full of fruit, will likely crack and fail.  The same practice of tipping the fruiting branches by one third works well.  Here in Marin, the main factor in peach production is not poor pruning, but either Peach Leaf Curl, a fungus disease, Taphrina deformans, or the timing of the blooms and our heavy rains.  -two future blogs to be sure.  Let's just say that if you want lots of peaches in Marin, you need to spray the trees at least once with a copper based spray while the tree is dormant and practice good garden hygiene.

Pear:  The nature of pear trees is to send up many water sprouts -whip like branches that go straight up.  Pears, like apples, fruit on spurs.  The trick is to thin out the water sprouts, and head them back to promote spur production while allowing good spacing and air circulation.  Generally, this means pruning the water sprouts back by about two thirds, using outward facing buds.  Pear trees, because of their tendency to shoot skyward, can get too tall too quick and need coaxing to create a productive, spreading canopy.  Removing the tall inner water sprouts at the growth ring can seem overly aggressive, but the response is worth it.  Here a note must be added that pears can succumb to a bacteria called fire blight, Erwinia amylovora.  This disease should be cut out, at least six inches past any discoloration (8-12" from some sources), the tools sanitized, and extra vigilance taken to identify and remove it from the tree and other nearby hosts.

Persimmon: Persimmons fruit on new wood near the tips of last years' wood.  They tend to have thin, weak branches and get too tall.  Thus, care should be taken on younger trees to establish a strong low framework with wider crotches, tall growth should be headed back severely, but last years' wood should not be reduced more than is necessary to keep the tree open and not too dense -it's true nature to begin with. -removing all of last year's growth means no fruit.  This holds true for both the predominant species.

Plums!  (and Prunes):  Both Japanese and European plums produce fruit on short branches, sometimes called spurs  (but not the same as apple spurs) that arise from older wood -so you want to maximize short fruiting spurs on wood that is two or more years old.  The best shape for plums is a funnel shape with sun getting into the tree and all the older fruit producing spurs.  These fruiting spurs will produce for six to eight years before needing to be replaced.  Generally, Japanese plums will require heavier pruning as they produce more water sprouts.  These water sprouts can be used to fill out "holes" in the canopy -when cut back to an outward facing bud, they will send out secondary branches that can then be cut back to form fruiting spurs -and be major fruit producers in only three years.  Older trees need to be thinned to reduce excessive shading but generally, most of the new wood is removed; All unwanted water sprouts are removed, those desired are headed back, and all new wood is cut back to the second or third bud, making sure as many short stubby interior branches ("spurs") are allowed to remain while they are kept short and strong to support the coming season's fruit and light is allowed to penetrate to keep those spurs productive over their eight year lifespan.

Pomegranate:  If a pomegranate is left to it's own, it will send up tons of upright branches that will quickly form a thicket of chaos.  start with trying to keep the tree to a one-stemmed plant.  Remove the numerous trunks that will grow from the original and duel for dominance.  Pomegranates fruit on short new shoots that arise from any wood that is more than one year old.  Larger fruit are produced if the canopy is well thinned and drooping branches are headed back to upright laterals.  The best variety for Marin seems to be one called 'Wonderful'... hard to go wrong with a name like that!

I'll put my favorite pruning books on my booklist found on my blog.  Please check in again soon as I'm excited to follow this blog up with Vines and Vine pruning...

Happy Gardening!

Winter Pruning: Basics

 This will be the first of a series of blogs.  I have realized that the topic is too large for a single blog.  Please stay tuned.

Pruning in the wintertime is different from mid-late spring pruning.  Winter pruning takes advantage of the deciduous state of many shrubs and trees, is more aggressive, and concentrates more on establishing framework.  Winter pruning is also a good time for sanitation.  Removing possible pathogens and their overwintering sites can promote better health in the coming season.

Over the years, seeing a fruit tree or rose grow in response to your seasonal pruning, producing abundant crops of fruit or flower, is one of the most satisfying feelings, right up there with good soil building.  I would hope that everyone gets a chance sometime in their lives to experience this wonderful feeling of good stewardship.

The major plant groups that one prunes in the winter are:

• Fruit Trees
• Roses
• Wisteria, Clematis, and other vines
• Japanese maples
• Misc. deciduous shrubs and trees -including flowering "fruit" trees.

These all take a different approach, discussed in upcoming blogs, but many of the basic cuts and concepts are the same:

The "Three D's":  Always remove Dead, Diseased, and Damaged wood.  This helps to limit access points for pathogens, help the plant take advantage of it's natural sealing ability, and gives the pruner something easy and obvious to start with, leading to a better assessment of what is next.  (One caveat: if you are trying to promote habitat generation, a certain amount of dead, diseased, and dying wood might be desirable -even a completely dead stump could be home to countless thousands of organisms, many of them being a good food source for beneficial insects, not to mention larger desirable avian species.)  Included in this would be any stubs or spikes.  Never leave stubs!

Crossing and Rubbing Branches:  In most cases, branches that cross back through the center of the plant should be removed.  Consideration is given to older branches and ones that make up a large part of the canopy or silhouette of the plant.  Rubbing branches are almost always removed as cambium damage is not worth the extra blooms or fruit.  Consideration may be given to those branches who have stopped rubbing and are fused together -self grafted.

Weak Crotches: The angle of the branch determines how strong the branch eventually is.  Because a woody plant will lay down layers of new wood around an existing branch, branches with wide crotches get stronger with age.  Branches with narrow crotches can develop included bark and get weaker.  Sometimes young branches may be trained with spreaders or tying back to create strong wide crotches.

Rejuvenating Cuts: These cuts are designed to re-invigorate the plant and are most common on cane plants, older roses, and even some larger shrubs.  This is the most aggressive of cuts, and may consist of removing the largest, oldest canes to the root crown.  Many plants can have their older canes removed after 3-4 years.  some examples might be Nandina, Abelia, Mahonia, some roses, and even large shrubs or small trees, such as lilacs, Cottoneaster, and Buddlea can do better when their oldest canes are removed, allowing new vigorous growth to take their place.

Suckers and WaterSprouts: Suckers originate from below the graft.  This is especially important on roses, dwarf fruit trees including citrus, and English walnuts.  Root stock is most often chosen because of it's inherent disease resistance and ability to do well in poor soil.  These tough plants will take over the grafted variety in most cases, given the chance.  A good rule of thumb is that any growth on the base of the trunk, and especially from the roots or below the swollen graft union, if existing, should be removed immediately.  WaterSprouts are those vertical branches that, in the previous season, shot skyward through the middle of the plant.  These water sprouts offer an opportunity to fill in the silhouette of a plant if there is a gap in the canopy.  Consider heading a water sprout back to an outward facing bud to establish a new scaffold branch.  Otherwise, water sprouts are thinned out at the growth ring.

Heading Back Cuts:  It's important to understand how the apical bud creates an auxin hormone that then travels down the stem inhibiting lateral bud growth.  "Tipping" can remove this plant hormone and promote branching.  Heading back to a lateral branch is a good way to reduce height and size of a plant.  Plants with long internodes respond well to heading back, promoting a shorter and stronger framework.  Heading back can also determine apical dominance where a central leader is desired or multiple leaders, as the case may be. "Topping" is not considered an accepted pruning method.  Heading back, as a general rule of thumb, is a viable method only if the lateral that is being cut back to is at least a third the size of the branch being cut.  This allows for ample "sap flow" and allows the tree to successfully seal the wound.  Heading back cuts are made at an angle from the outer edge of the branch bark collar and bisecting the angles between being perpendicular to the branch being removed and the one being left.

Thinning Cuts:  These cuts, as the name implies, thins out the plant, promoting good air flow, reducing week crotches, and establishing symmetry and good structure.  All thinning cuts are made just outside the growth ring.  Plants have strong natural abilities to seal their wounds quickly at the growth ring.

Directional pruning at a bud:  Plants have buds and internodes.  The direction of the bud will determine which way next season's growth will be directed.  Generally, these cuts are made roughly an 1/8th of an inch past the bud at a slight angle away from the bud.  Also, as a general rule, buds facing away from the center of the plant are favored.

The Three-Saw Cut:  This is a method of removing a larger branch safely and eliminate the possibility of ripping the bark away from desirable wood.  This is accomplished by making the first cut on the base of the limb being removed, the second cut being made on the top FARTHER OUT on the limb.  The distance between these two cuts is determined by the type of wood, the size of the limb, and the weight involved.  (It also makes the difference between a "hinge cut" where the branch can hinge down and fall foliage first or a "jump cut" where the branch is removed and falls more horizontally.)  This procedure can be repeated on larger limbs working down to the desirable wood.  The Final Cut is made just outside the growth ring.

Words of Warning and General Safety:

• The 30% rule of never removing more than a third of a plant at one time is a good general rule to consider, especially with evergreens.
• A sharp tool is a safe tool:  Sharp tools take less energy, demand less force, and make better cuts.
• If pathogens are a concern, disinfect your tools.  Lysol or a bleach solution works well.
• The sign on the top of the ladder saying to stay off the top rungs is a serious warning and should be followed.  Always make sure all the legs of the ladder are secure.
• Use the "three point contact method" when climbing in a tree:  always have two hands and a foot or two feet and a hand in conscious contact while moving and pruning.
• Wear a helmet, and a rope and saddle when appropriate.  Use a tagline.  80% of falls over 20 ft. are fatal.  Never get into a situation where this rule is relevant while alone.  Avoid climbing in the rain or when exhausted.

Alright, enough of the basics and safety.  On to the good stuff!

Extending your garden enjoyment into the evening

 Outdoor lighting in an area such as Marin can make a huge impact on the amount of enjoyment one gets out of their garden.  Our climate here is so mild that early spring, late fall, and even some winter evenings can be very enjoyable to spend outdoors if it's not too dark.  A simple outdoor lighting system can allow you and your loved ones to enjoy your garden and entertain your friends well beyond sunset.  In addition to spending more evening time in the garden, outdoor lighting provides a wonderful medium to highlight garden accents, specimen plants and trees, and play with shadows, silhouettes, and even color.  The combination of increased safety, security, and aesthetics are enough to warrant getting outdoor lighting.  The opportunity to enjoy your garden later in the evening makes it even more appealing.  And it's easy!

Some of the fixtures available today are stunning in their shiny copper, brass, stainless steel, or even custom craftsman pieces with glass or custom torched copper.  I like to use high quality lamps but get them in black or matt bronze or un-finished copper so they patina well and then do my best to hide them.  I think a good lighting job lights up the landscape rather than show of a bunch of fancy fixtures.  That having been said, if the house has a front entry sconce or fixture, it's great to get path lights that echo or compliment that style.  

  The ideal system is a "line volt system" -120 volts.  This is the same voltage as used in your home.  This high voltage reduces the amount of resistance ( ohms ) and allows lights to be further away from the electrical source.  However, 120 volts is dangerous.  Wires  carrying this load must be encased in conduit and under 18" of soil or 6" below concrete.  All connections must be in water tight junction boxes, and pull boxes must be located not more than 50' apart and between no more than 2 "sweeps" (turns) in the conduit.  It's also REALLY important that the electricity be turned off when working with this type of system. These reasons make this type of system much more expensive, potentially dangerous, and not so easy.

The "Low Voltage" alternative is by far the most efficient, safe, and economical.  Still, you get what you pay for;  Those boxes of 12 lights, a transformer,and some wire that you get at the discount stores for $50 will NOT be very satisfying.  Usually these last (maybe) two years before falling apart.  Also, they tend to have very little wattage per light.  While you can see them, they do not illuminate anything.   These are best used as "runway" lights so you can see the edge of the driveway.  They don't do much for ambiance in the garden.   There are also fiber optic systems, but those are best reserved for professionals to install and are still quite expensive, although very safe in water situations.  I have yet to see a quality solar light.  There are a lot out there, but unfortunately they are priced to sell, not last, and I've never seen one that did a good job and lasted more than two seasons.  There IS a market for this.  Someday someone will make a good one.  I have used some great paver lights.  These go right in the pavers of driveways and can handle being driven over.  

Low voltage refers to lights that are designed to work around 12 volts.  At this voltage, they are not dangerous if installed correctly and the wires can be run right under the mulch with no conduit.  To get line voltage (120v) down to 12v, you need a "Transformer".  These come in many sizes and complexities, but generally come in 250 watt, 300watt, 500 watt, 600watt, and 900 watt options.  Most of the better transformers offer optional timers, photo cells, and multiple voltage outputs along with separate fuses and switches for each 250 or 300 watts of output.  The reason for the multiple voltage outputs is to address voltage drop.  The longer the wire, the more voltage drop there is.  You can mitigate this with larger gauge wire, but it's best to design a system in groups of lights and work well within the limits of the wire you are using and have the option of using up to 14 or 15 volt outputs available on the transformer.  Lights work best if they are at 11.5 volts, generally, and should not recieve less than 10.8 or more than 12 volts.

LED bulbs are revolutionizing the Low Voltage industry.  All the manufacturers are now coming out with LED (Light Emitting Diode) fixtures and bulbs.  These new bulbs use MUCH less watts and allow you to put many more lights on a single wire or transformer, generally by a factor of x3 or even x4 or more.  While the traditional path light would use 20-35 watts, the new LED fixtures only use 3-9 watts.   While LED bulbs still do not put out the warm glow that incandescent lights do, this can be mitigated with the use of color filters, diffusers, and frosted lenses.  These systems decrease energy costs, transformer and cable costs, lower lamp heat, and last for much, much longer before having to be replaced.  They are the future of landscape lighting.

There are many ways to design lighting systems.  Here are a few rules of thumb to consider:

• Always take into account that more lights may be added later: don't max out the transformer on the first installation.
• Electricity ALWAYS goes in a circle: out on one wire, through the fixture, and back to the transformer on the other wire.  Don't cross the wires.
• Always take into account what the maximum wattage bulb is for any fixture.  If you are using LED bulbs that COULD be replaced with standard bulbs, you might consider designing the system for standard bulb wattages.
• Group lights together by proximity -or consider separate transformers for different areas/uses.
• Shoot for 80% of your total wattage load on the transformer, keeping in mind the 250 or 300 watt output limitations on the transformer.
• Transformers use a 10-1 ratio; if you only have 115 volts, you'll only have 11.5 volts going out on the "12v" lead.
• Don't exceed 16 amps or 200 watts (192 is recommend by some) on a 12 gauge wire; 24 amps or 288 on a 10 gauge wire (200 watts is still a good rule of thumb here)
• Don't exceed 200 ft. with 12 gauge wire or 400 ft. with 10 gauge wire.

It's best to do the calculations for wire sizing, but a general rule of thumb (to be super safe) is to keep the distance of wire x the watts used below 7500.  That's 100 watts on 75 ft of 12-2 wire using 12 volts.  There's lots of variables and in reality, you can exceed this (a lot) with larger wires, higher voltage outputs, and play with the watts used vs. the distance, but it's nice to have a simple system that allows for a simple installation and leaves room for additional lights.  Also, in reality, designs that require different sized wires for different runs rarely get followed in the field and it's safer to assume that 12-2 wire will be used.  Having the multi-volt output on the transformer makes a big difference.

Use a volt meter and test the voltage at the fixtures; Use an amp meter and test the amps in the wire.

Here's a couple formulas and some constants that are helpful:

Amps = Watts/Volts

Amps x Distance x 2 x (Resistance/Ft) = voltage drop

Resistance/Ft Chart:

• 12 gauge: .00162
• 10 gauge: .00108
• 8 gauge: .00064

I like this easy chart using all 12 gauge wire:

• 11Volt: up to 40' with 160 watts
• 12Volt: 40 to 60' with 120 watts
• 13Volt: 80-120' with 100 watts
• 14Volt: 120-160' with 60 watts

Here's a chart that uses different gauge wires depending on the distance from the transformer:

up to 40':

• 12 gauge: 160 watts
• 10 gauge:220 watts
• 8 gauge: 280 watts

40'-80':

• 12 gauge: 120 watts
• 10 gauge: 200 watts
• 8 gauge: 280 watts

80-120':

• 12 gauge: 80 watts
• 10 gauge: 140 watts
• 8 gauge: 200 watts

120-160':

• 12 gauge: 60 watts
• 10 gauge: 100 watts
• 8 gauge: 160 watts

While all the formulas and rules can be a bit confusing, and each supplier and contractor will say they have the best system ( Loops, Split (Tee), Straight Run (Daisy Chain), or Hub) it all comes down to putting three to six lights in a group in one area and running a wire back to the transformer from there.  Add up the watts, allow about 20%, and don't exceed the transformer's output.   

Splices:

 I like to use wire splices that have a copper crimp and a gel filled cap to be sure there's a good connection that can't be pulled apart, and it will work under water -but they're expensive, about $2 each.  If you like using electrical grease, use lithium based ones.  Please don't use wire nuts and electrical tape.  This will eventually corrode and fail.

Wire Runs:

Always run wires along or perpendicular to walkways, buildings, etc.  Never weave wire through a planting bed.  Use "jute staples" to secure the wire.  Make note of where sleeves are under walkways and driveways.  If possible, label the wires coming into the transformer.  Leave extra wire at each light.  All these practices makes servicing and trouble shooting a system much easier down the road.  

Outdoor lighting is a big topic.  This is a good first blog to get you thinking about the possibilities.  Happy Gardening!

Welcome to my new Garden Blog!

Hi and Thanks for checking in on my new Marin Landscape and Garden Blog.

It's exciting to be experimenting with all the social media.  I've found some great new networks, many wonderful contacts, and fantastic green thumbed friends so far and I believe I'm only touching the moist loamy surface.  The whole wide world of garden blogging is an eye-opener, and so much fun.  All the Garden Tweeters are almost overwhelming, but I'm slowly getting used to it.  My network on LinkedIn has been growing steadily, and I'm excited about posting the new Marin Landscape and Garden MeetUps.

I've also been working on a website of Landscape and Garden information and links using iWeb and my .mac account.  I'll link to pages in that site from various blogs as appropriate.  Many pictures of Gardens & Gables project are and will be available there.

I'm also particpating in the 2010 Marin Master Gardener program.  I'll keep my Blog followers posted and up to date as our gardening topics are revealed.  This is going to be fun.

Thanks for visiting.  Please friend me on Facebook, Join my network on LinkedIn, follow my blog, and join us at our upcoming Marin Landscape and Garden MeetUps.  We're going to have a blast.  Links to all these and more are on my profile page.

Get your boots on, your Felcos at your side, your most trusty spade at the ready...

Happy Gardening!!!

~Dave

 

Uncle Jake's Framing Sizes

When I was in college I took a class from a unique professor.  It was a special experience.  Everyone has stories about professors they had that were unique in some way, or made a big impact on them.  Uncle Jake was one of those professors.  Just like Einstein, Jake had acquired the habit of wearing the exact same thing every day.  You see, he was an engineer.  It was logical and efficient to figure out the best clothing and then wear it -all the time.  The best part was that he had figured out that it was most logical and efficient to have tools for recording things with  him at all times.  Thus, on top of his comfortable blue button up shirt he wore a kaki fishing vest covered with pockets and filled with note pads, camera, pens and pencils, rulers, tape measurers, calculator... you name it.  Just like the boy scouts, he was prepared.  Always.  He would show us movies of his trips around the world over the years as he explored ancient architecture.  He always had the same uniform on.

Unlike most of the engineers at the School of Architecture and Engineering, he had a soft spot for Landscape Architecture students.  I think he pitied us. We were not destined to be REAL engineers or required to take REAL engineering classes.  Regardless, it was our only class that really taught us anything about how to actually BUILD stuff.  It was a great class -one of my favorites.  He had us building models of actual concrete retaining walls, geodesic domes, miniature decks, and the like.  Unlike most of my college notes, there was a hand out that he gave out that I have referred to over and over again.  I saw a copy of it posted on the wall of our office the other day...about 19 years after he handed it out.  It was his Deck Framing Sizes charts.  Uncle Jake had many "rules of thumb".  He called them something like "Te Cule Gumba"... or something like that.  It was "rule of thumb" in some esoteric language; I forget which.  We learned many rules of thumb in his class and most of them were just shy of genius.

Anyway, what he had done was take redwood and doug fir and make a chart for spans and cantilevers for various sizes, giving a bit of a safety factor and allowing for a substantial live load on a deck.  These "rules of thumb" are so easy to use and allow decks, arbors, and just about anything to be designed with confidence without the need to compute the actual statics of the construction.

***Important stressed Point:  These are Rules of Thumb; not engineered!  (But I've used them in many varied situations over the last two decades and never once had a problem or any disagreement from any building department.)

So, Here they are, with some discussion to follow:

Download JakesFramingChart

As you can see, Post spacing is equal to the Beam Span and equals in feet what the height of the Beam is in inches.  Beams can cantilever (stick out beyond the post) in Feet half of what their height in inches is. 

These rules of thumb make it easy to size the dimensions of wood necessary to build decks and arbors with confidence.  This IS more than an arbor needs to be, but after seeing so many arbors laden down with huge Wisteria and the like... with people up on top pruning... I've usually tried to stick to these rules of thumb where practical.

I hope these charts will be as helpful to you as they have been for me over the years.  My deepest gratitude and thanks go out to Uncle Jake, for making school so much fun!

Garden Gateways

The entrance to a space sets the tone for the coming experience.  Preconceptions of the impending experience are set and feelings and emotions are put into play from past experiences.  These memories form expectations that establish the context in which a person experiences a space.  By utilizing the different senses of scent, touch, and sound, stronger contextual feelings are created.  The mind finds past neural pathways and prepares for similar outcomes.  These mental expectations can sometimes be stronger than the actual experience.

The crunch of gravel underfoot, the smell of gardenia blossoms or lavender, the quick darting of hummingbirds, or the sound of a gurgling fountain or stream can evoke powerful responses as a person prepares to enters a space.  An entrance or gateway can be used to create an endless array of emotions.  Entrances can be imposing and scary and trigger the fight or flight reflex of dumping adrenalin into our system.  They can also be enticing, with views of a comfortable path leading inside, with hints of warmth, protection, and enjoyment ahead.  Because of the importance of the gateway setting the tone for a garden space, the concept has been studied for thousands of years.  An example of a set of guidelines is Feng Shui, where the gateway establishes how the flow of energy or ch'i enters the garden.  Depending on the direction of the entrance, the ch'i is different and needs to be dealt with differently.  South facing entrances need to be filtered to slow down the ch'i.  North facing entrances need to be opened up to help the ch'i enter.  Feng Shui can help decide what color to paint a gate, what material to use, and even how to prune a tree near or over an entrance.  Accommodating a smooth flow of energy makes sense for most entrances, but the desired visitor's reaction is what should be considered.

Also of concern is local planning and building codes.  Many times an entry gate is dictated by the restrictions of front set backs, fence height limits, vehicular sight lines, and perhaps even necessary approval by the homeowners association of the neighborhood, right down to the color of the trim.  It is fun to think about designing gateways for a large "multi-room garden" or park where separate interconnected spaces all have transitional gateways that prepare or surprise the visitor as they move through the different environments.  For the most part, my client's entryways are to a front yard space accessed by both the street and a driveway.  There is usually a secondary path leading to a side gate and a main path leading to the front steps of the house.  It is important that guests feel comfortable, that the path to the driveway is wide enough, and that there is something along the way of interest as well as a place to rest, if only symbolically.  It is highly desirable for  there to be a pedestrian entrance from the street and not force visitors to squeeze past vehicles on a driveway to enter the area.  Likewise, if guests park on the side of the street, allowing for pathways through the sidewalk planters and space to open doors makes sense.   A small patio with a bench accompanied by a collection of planting containers is a classic way to provide a symbolic resting space in an entry garden.  Some sort of accent, such as a small water feature, a statue, a bird bath... or an interesting plant... should be a part of the entry experience.  There should be a nice flow to the entry circulation without sharp turns and the hierarchy of the various paths should be immediately apparent.  Utilities such as garbage and recycling bins should be accessible but hidden.  It is best to have the entry gate off set to the front door with a pleasing "s" curve, not a straight line from street to door.  The front entry path or steps should ideally be splayed so that circulation from various directions are accommodated and directed smoothly.

  The choice of materials is best done by addressing the house and the occupants;  Sometimes it is desired to emulate strong architecture or create grandeur.  Most times, it comes down to budget.  Stone and wrought iron are nice, but wood and plants can do the job -sometimes better.  The best way to determine the materials and details is to take a moment on site and reflect on the "genius loci", the pervading spirit of a place, and go with that, modifying it to the temperament and desires of the occupants.  It's hard when someone wants a white picket fence and a cottage garden entrance when they live in a mediterranean climate and also want low maintenance.  Ultimately, the gateway to a garden should prepare the visitor for meeting the owners of the home.  Real estate professionals talk about "curbside appeal".  This usually means that the entry has character, is nice to look at, and is inviting, never invoking hard work to maintain.  Use nice clean lines, soften walls and fences with plants, and provide a sense of safety and of welcome with wide, sturdy, well defined, and well lit paths.

Gates and arbors are best when they echo the architecture of the house.  They need to be sturdy.  If you are hanging a gate on a post it should be at least a 4x6.  Using three hinges instead of two makes a big difference.  Spring loaded hinges make sense if there are pets, kids, or deer in the picture.  Self closing latches also provide great utility.  I've come to appreciate magnetic latches that snap closed as the gate closes.  While it might seem like a good idea to have a double gate, many times the necessary cane bolt is not considered in this decision.  Also, if one wishes an arbor of wisteria or virginia creeper over an entry way, you must plan to support the future weight.  Having a way to peer through into part of the garden while the gate is closed is a big bonus and worth the extra effort every time.

KhaKha Powder?

I've been using a product to stabilize both decomposed granite and blue pathway rock.  There are many stabilizing products produced for this use, but the suppliers usually shrug when you ask what, exactly, this "Stabilizer" is.  "It's natural", they tell me.  Yeah... so,  WHAT is it?

After seeing a larger bag with the ingredients listed, a little research has gleaned a lot of understanding.  It IS a natural product, but it comes a long way to get here... coming from India, I'm not sure how it's carbon footprint would add up, but essentially it's the by-product of husking Psyllium seeds.  Psyllium, Plantago Ovata, is a large grass plant that is planted on a large scale in western India where it thrives in the salty, sandy soil.  It is used in many industries, but most importantly, the pharmaceutical industry for it's ability to remedy constipation, regulate bowel functions, eliminate toxins, and lower cholesterol.

Psyllium Kha Kha Powder works great to help mitigate erosion with decomposed granite and other fines such as blue pathway rock.  The recommended rate is 10 lbs per cubic yard of material and comes in 5 lb. bags for $25.  This may seem expensive until you compare it to Gator Dust at around $32 for 50 lbs of pre-mixed material or Terra Pave produced by Wheeler Zamaroni which recommends applying their product using asphalt laying equipment.  These products all have their uses.  If you're considering a driveway or large commercial path, Terra Pave is the way to go.  If you're filling cracks in old concrete where the wood expansion joints have rotten out, or just have joints between stones 1/2" to 4" wide, go with Gator Dust.  -But for general garden paths, if you've got any slope at all, this will help keep the material from washing out in a heavy rain.  I like to make the path, grade and compact, then put the rock fines in place in a windrow.  Level out the top of the windrow and apply the stabilizer product.  Mix in and level at the same time, compact again, and water well.  This will NOT keep all the small stones on the surface from sticking to shoes or being blown away by over zealous pack pack blower users, but it will mitigate erosion to a large degree.  On existing decomposed granite or blue pathway rock paths and patio areas, this material can be added with a soil rake... but it's a lot of work.  I've had good luck filling in rill erosion channels with Psyllium powder and stone... and it doesn't erode anymore.