Mulching chestnut trees


Biochar vs. Wood Chips

People are funny. Take, for instance, a fellow gardener who, a couple of months ago, shared with me her excitement about a biochar workshop she had attended. “I can’t wait to get back into my garden and start making and using biochar,” she said.

Biochar, one of gardening’s relatively new wunderkind, is what remains after you burn wood with insufficient air. It’s charcoal. Stirred into the soil, its myriad nooks and crannies provide an expansive adsorptive surface for microbes and chemicals, natural and otherwise. Biochar, being black, darkens the soil, and dark soil is generally associated with fertility, although that’s not always the case. Because biochar is mostly elementary carbon, it resists microbial decomposition, so it’s carbon is less apt to end up in the atmosphere as carbon dioxide.Biochar

In contrast, when raw wood — wood chips or sawdust, as examples — are added to soil, it feeds microbes and then plants as it decomposes, eventually turning to organic matter, sometimes called humus. Humus is a witch’s brew of compounds with beneficial effects on soil’s nutritional, biological, and physical properties. So is cooking up a batch of biochar and digging it into your soil better for the soil and really worth the effort?

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Spreading Limestone!

Visiting Clyde (not his real name), a farmer friend, one summer day a few years ago, I came upon him sprinkling some white powder along a row in preparation for planting. In response to my wondering what he was doing, he said he was spreading limestone. I was surprised.

In much of the eastern part of the U.S., unless you grow only native plants, or a rather narrow spectrum of exotic plants, you probably do have to do something to make the soil less acidic. And remember, tomato, apple, peach, marigold, rose, and many other plants in our gardens are exotics. Not only are many soils in the East naturally too acidic for most of what we grow in our gardens and farms, but soils here always are becoming more so.

Acid rain is one reason for this, but even before acid rain, the abundant rain that falls in this part of the country has been leaching soils and making them more acidic since time immemorial. As a general rule, areas where rainfall — not necessarily acid rain — exceeds about 30 inches per year, enough base-forming ions such as those of calcium, magnesium, and potassium get leached down and out of the ground to make soils more acidic.

But that’s not all. Calcium, magnesium, and potassium are plant nutrients, so harvesting crops takes them off site, increasing soil acidity. Some fertilizers, such as those that contain nitrogen in the form of ammonium, also make soils more acidic.

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Your Pet Needs:

As the bumper sticker on my truck reads, “COMPOST HAPPENS.” Even so, problems sometimes arise along the way.Compost happens bumper sticker

Is your main complaint that your compost “happens,” but too slowly. I like to picture my compost pile as a pet, except this pet is made up of many different kinds of macro- and microorganisms, and the population changes over time. Like other pets, my compost pet and your compost pet need food, air, and water.

Compost piles work quickest when their two most important foodstuffs — nitrogen and carbon — are in balance. (All this, by the way, also applies to us humans; our nitrogen comes mostly from proteins, and our carbon comes mostly from carbohydrates.) Old, usually brown and dry plant materials, such as autumn leaves, straw, hay, and sawdust, are the carbon-rich foods for a compost pile. Carbon-rich compost foodThe older the plant material, the richer it is in carbon. Nitrogen-rich materials include young, green plant parts, such as tomato stalks, vegetable waste from the kitchen, and grass clippings, as well as manures.Nitrogen-rich compost food

Nitrogen fertilizers are concentrated sources of nitrogen. They commonly are the active ingredients of commercially available compost “activators.” “Activator” has a nice ring to it, but it is overpriced, unnecessary, candy for any compost. Sometimes they also contain microorganisms, also unnecessary.

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Go Drip!

This summer has been one of the hottest and driest ever — and it’s been one of the best ever in the vegetable garden. Baskets of red, ripe tomatoes and peppers sit on the kitchen floor awaiting metamorphosis into sauces and salsas, dehydration, or just plain being eaten.Dog Sammy and garden beds

What about water? My garden plants are plump with water thanks to drip irrigation. In addition to benefits to the plant, drip is also good for the environment, typically using only about 40 percent of the amount of water used by sprinkling. That’s because the more pinpointed water avoids wasting water in paths and other places it’s not needed. Also because little water is lost to evaporation.Dripline with beans

The “drip” in drip irrigation tells you that water is applied at a very slow rate, which is especially appealing to those of us whose water comes from a well. With drip, the well has plenty of time to recharge between waterings.

Drip is also better for plants. Leaves stay dry, lessening the chance for disease. And rather than flooding the ground, which a sprinkler does at each watering, drip keep soil moisture within that happy window when larger pores remain filled with air, and water is held within smaller pores so that roots can both breathe and draw in water. (This is one reason for the more efficient water use of drip irrigation.)

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First Step, Identification

A few years ago I went to a nearby permaculture convergence. (Actually a “permaculture conference; those people have the best terms for what they do). I’ve grown plants in what I learned was a permie way for many decades, so I’ve been accused of being a permaculturalist. I was even invited to do a presentation and host a farmden tour for the convergence.

While there, I had the opportunity to attend a lecture by someone who has been billed as the diva of dirt, or, at least, of compost tea, specifically aerated compost tea (ACT), Dr. Elaine Ingham. You’ve never heard of ACT!? It became the hot, new thing years ago, perhaps still is, as an alleged cure for poor soil and plant pests. I’d been skeptical and thought that hearing and speaking to Dr. Ingham in person could entice me into the fold.Making compost tea

  Dr. Ingham showed myriad images of fungi, nematodes, and other creatures that you might find in compost piles and teas. We saw many “bad guys” that lurk in poorly aerated composts and teas. The “bad guys” are bad, she asserted, because they release toxins into the soil and puff away valuable nitrogen, sulfur, and phosphorus in various forms as gases.

  Dr. Ingham suggested monitoring our compost piles and tea happenings by purchasing a microscope and, with the help of her workshops, identifying resident microorganisms. Hmmm; interesting, but is it really necessary for a green thumb?

  While the panoply of microorganisms discussed was impressive, I contend that even a well-aerated compost pile or tea is bound to have some poorly aerated pockets. It’s not a “bad guys” vs. “good guys” situation, but a question of generally favoring an excess of “good guys.” Also, once compost is spread on the ground, the large surface area presented is going to tip the balance even more in favor of aerobic conditions.

To identify what organisms are in a compost pile, you have to get them out of the pile and onto a microscope slide. Easy. Just soak some compost in water and strain it. Or use a compost teabag. But wait! Is that really the spectrum of microorganisms that call that compost home? Not necessarily. What are staring up at you from that microscope slide are creatures that can be leached most readily into water. What you see also might depend on how long you steeped the teabag and who can squeeze out into the water through whatever size holes are offered by the strainer or the teabag.

Will Compost Microbes be Happy Far from their Compost Home? More fundamentally, I question basic assumptions underlying the use of compost tea. Even if you have beneficial organisms in hand (figuratively) and sprinkle them on the ground, they’re bound to expire unless the environment is suitable. Microorganisms in the tea might have enjoyed life within the dark, moist innards of a compost pile; the soil environment ain’t nothin’ like home for them.

Spraying ACT or any compost tea on plant leaves should likewise have little or no effect on plant diseases; again, conditions on a leaf surface aren’t conducive to their survival. In the evolutionary scheme of things, why would a microorganism that thrives in the dark, moist, nutrient-rich innards of a compost pile survive on the sunny, dry, nutrient-poor surface of a plant leaf, let alone provide any benefits?Spraying plants

Over the last few decades, people have spritzed plants and sprinkled soils with compost tea, looking for effects such as improved soil structure or drainage or increased plant resistance to pests. Independent well-designed, vetted studies do not generally support claims made for compost tea.

True, there are some studies that show some benefits. I contend that if you spray just about anything on a plant leaf and have enough plants in the study along with sufficiently detailed measurements, some statistically significant effect might be noted. But every statistically significant effect isn’t also biologically significant. And looking over a number of studies, some few show a benefit from compost tea, many demonstrate no effect, and for a number of them, the effect of compost tea is detrimental.

Soluble nutrients do leach out of a compost teabag into water. The resulting compost tea, then, becomes a liquid feed for plants, effective either poured on the ground or even sprayed on leaves. So there can be some benefit from compost tea, a nutrient effect, not a microbial one.

Bulk is Good

Except in special situations, soil environments naturally host microorganisms that thrive best in them. A similar situation exists with earthworms. Years ago, perhaps still, advertisements in the back pages of gardening magazines would offer earthworms for sale. The reasoning went that good soils are teeming with earthworms, so purchasing and importing these creatures to you garden will make your soil better. Not true. The earthworms will die out if conditions and food are not to their liking. The same goes for microorganisms.

(An example of an exception to what I wrote in the previous paragraph is a study that was done in Puerto Rico back in 1950. THE USDA was trying, with little success to introduce a more useful, but non-native pine, to the island territory. Mycorrhizae are fungal symbionts that infect practically all plants; the fungus gets some foods manufactured by the plant in return for moving more nutrients and water to the plant for improved growth. The appropriate fungal symbiont was lacking in Puerto Rican soils. After inoculating plants with an appropriate fungus, the inoculated, introduced pines grew six times more than their introduced brethren that had not been inoculated.)Compost being shovelled

Except in rare situations, as in the example above, earthworms, microorganisms, and other creatures generally inhabit environments most congenial to their flourishing. Perhaps not enough of them, and what they really need is food to give their populations a boost, and food means some form of organic material. That is, bulky organic materials, such as compost, manure, leaves, and straw.

  Good gardening comes form using a pitchfork, not an elixir. Does anybody still make and use compost tea?


Prime Ingredients for Any Potting Mix

Many years, my gardening season begins on my garage floor. That’s where I mix the potting soil that will nourish seedlings for the upcoming season’s garden and replace worn out soil around the roots of houseplants. Why do I make potting soil? Why does one bake bread?

There is no magic to making potting soil. When I first began gardening, I combed through book after book for direction, and ended up with a mind-boggling number of recipes. The air cleared when I realized what was needed in a potting soil, and what ingredients could fulfill these needs. A good potting soil needs to be able to hold plants up, to drain well but also be able to hold water, and to be able to feed plants. The key ingredients in my potting mix are: garden soil for fertility and bulk; perlite for drainage; and a mix of peat moss and compost for water retention. 
Components of potting soil
Why not just dig up some good garden soil? Because a flower pot or whatever container a plant is growing in unavoidably creates “perched water table” at its bottom. Garden soil, even good garden soil, is so dense that it will wick too much water up from that perched water table. Waterlogging is apt to result, and waterlogged soil lacks air, which roots need in order to function. (More about perched water tables and lots of other stuff about soil, propagation, plant stresses, and more can be found in my book The Ever Curious Gardener: Using a Little Natural Science for a Much Better Garden.)
Perched water table
Coarse mineral aggregates — perlite, in my mix — make potting soils less dense, so water percolates more readily into the mix, through it, and out the bottom of the container. Other aggregates include vermiculite, sand, and calcined montmorillonite clay (aka kitty litter). I chose perlite because vermiculite breaks down with time and can contain asbestos. Sand is heavy, although this can be an effective counterbalance for top heavy cactii.

The peat moss and compost in my mix are organic materials that slurp up water like a sponge; plants can draw on this “water bank” between waterings. One peat to avoid is “peat humus,” a peat that is so decomposed that it has little water-holding capacity. Organic materials also buffers soil against drastic pH changes and cling to nutrients which are slowly re-released to plant roots. Otherwise these nutrients run out through the bottom of seedling flats and flower pots. 

Peat is relatively devoid of nutrients but the compost provides a rich smorgasbord of nutrients. And I can brew it myself. Just letting piles of autumn leaves decompose for a couple of years produces “leaf mold,” which has roughly the same properties as compost.

Potting soils made with garden soil and compost might need to be pasteurized to eliminate pests especially weeds. Too much heat should be avoided, however, because toxins which injure plants will form and beneficial organisms will be eliminated. When I am going to pasteurize, I do so only to the garden soil in the mix; my composts get to above 150°F all on their own.

To pasteurize potting soil, put it in a baking pan, bury a potato in it, and bake it in a medium oven. When the potato is baked, the soil is ready. Pasteurization is not absolutely necessary; I pasteurize to kill weed seeds.Begonia, Mandarin & cats

What You Buy Isn’t . . . 

Go out and buy a potting mix and, in all likelihood, that mix will be devoid of any real garden soil. You can mix up a so-called “soil-less” potting mix by sieving together equal volumes of peat moss and perlite. Since the mix has no garden soil or compost to supply nutrients, add 1/2 cup of dolomitic limestone, 2 tablespoons of bone meal, and 1/2 cup of soybean meal to each bushel of final mix. This mix has enough fertility for about a month and a half of growth without additional fertilizer.

I favor traditional potting mixes, which contain real garden soil. Real soil adds a certain amount of bulk to the mix, as well as a slew of nutrients and microorganisms. Real soil provides buffering capacity, which allows for some wiggle room in soil acidity.

The Magic Happens

I wrote early on, “There is no magic to making potting soil.” I could toy with ratios and make a potting mix from perlite plus compost, perlite plus compost plus garden soil, even straight compost, depending on the texture of the compost.

Going forward, I’m going to experiment with coir and/or PitMoss, both possible substitutes for peat moss, the harvest of which is environmentally questionable.

For my first batch of potting mix for this season, I’ll stick with my usual recipe. Step one is to give the garage floor a clean sweep. potting soil, piling ingredientsThen I pile up on the floor two gallons each of garden soil, peat moss, perlite, and compost. On top of the mound I sprinkle a cup of lime (except if I’ve sprinkled limestone on the compost piles as I build them), a half cup soybean, perhaps some kelp flakes.

This is a mixed bag of ingredients, but I reason that plants, just as humans, benefit from a varied diet. I slide my garden shovel underneath the pile and turn it over, working around the perimeter, until the whole mass is thoroughly mixed. potting soil, mixingI moisten it slightly if it seems dry. When all mixed, the potting soil gets rubbed through a 1/2″ sieve, 1/4” if it’s going to be home for seedlings.potting soil, sifting

I end by clicking click my heels together three times and reciting a few incantations to complete this brew that has worked its magic on my seedlings, houseplants, and potted fruits each season.


What Does “Salt” Really Mean?

A few years back, one of my neighbors planted a hemlock hedge along the road in front of their house as a screen from the road. Sad to say, the future does not bode well for this planting. The hemlocks very likely will be damaged by road salt.  And the prognosis is similar for those stately sugar maples that line so many streets. Truck spreading saltChemically, road salt — at least the more traditional “road salt” — is the same as the stuff in your salt shaker, sodium chloride. Either sodium or chloride ions can be toxic to plants. Chlorine is a nutrient needed by plants, but it is classed as a micronutrient, needed in minute quantities. Too much is toxic. Sodium is not at all needed by plants.

In a broader sense, a “salt” is any ionic molecule, that is, a molecule of two or more atoms in which electrons, which are negatively charged, are donated from one atom to another. Who gets what depends on how easily an atom or atoms can lose one or more electrons and how hungry another atom or atoms is for those electrons. That ability to donate or be hungry for an electron depends on the number of positively charged protons in an atoms nucleus and the number and arrangement of electrons around the nucleus.

In the case of table salt, the sodium easily loses one electron and the chloride atom is hungry for it. The once neutral sodium atom becomes, after losing an electron, a positively charged sodium ion. The once neutral chloride atom, after gaining an electron, becomes a negatively charged chloride ion. And bingo, these two oppositely charged ions are strongly attracted to each other; they bond.Salt and water ionsWhat happens when water enters the picture? A water molecule, because of its shape has a slightly imbalanced charge distribution. The negatively charged side of the water molecule gets attracted to the sodium ion of table salt, and the positively charged side of the water molecule gets attracted to the chloride ion. 

Salt Problem in Winter, and Beyond

Any salt (ionic molecule), not only sodium chloride, attracts water so will simulate drought if in excessive amounts in the soil in the same way that potato chips dry out your lips. This leads to common symptoms of salt injury. First evidence of salt injury is browning of leaves, starting along the leaf margins. Early fall coloration and defoliation also can occur. More severe injury is manifest by twig or branch dieback, or death of a whole plant.

Progressive symptoms of salt damage

Progressive symptoms of salt damage

Salt also has an adverse effect on the soil itself, which is particularly insidious since it’s not as obvious as a dead plant. Over a period of time, sodium in salt can pull soil particles together, squeezing air out of the soil. As a result, roots suffocate.

Plants suffer most from salt in dry soils, so any plant exposed to salt in winter will benefit from mulching and watering during summer droughts. Watering also leaches sodium out of the soil, which improves soil porosity. Gypsum further aids in fluffing up a soil made too compact by sodium, by displacing sodium in the soil with calcium.



Plants vary in their tolerance to salt. In addition to hemlock and sugar maple, the following trees and shrubs should not be planted where they will be exposed to salt: red maple, American hornbeam, shagbark hickory, dogwoods, winged euonymus, black walnut, privet, Douglas fir, white pine, crabapples, beech. Plants with a moderate tolerance to salt include: Amur maple, silver maple, boxelder, red or white cedar, lilac. Deciduous plants with high tolerances for salt include: Norway maple, paper and grey birches, Russian olive, honeylocust, white or red oaks, black locust, and many of the poplars and aspens.

For my neighbors who wanted an evergreen hedge, better choices would have been: white spruce, Colorado blue spruce, or Austrian pine. Perhaps even yew, since the site was somewhat shaded.

Mitigation or Avoidance

An obvious way to limit problems with road salt on plants, even salt that you might spread on your driveway or paths, is to use less salt, or none at all. (After once slipping on ice in my driveway and suffering a slight concussion, I became very aware of weighing damage to plants against damage to humans.) Fortunately, there are ways to keep all creatures happy.

Traction on ice or snow can be increased by spreading sand or sawdust.

A very effective technique, one that uses less salt, used by some road crews is to spray a salt solution on dry roads before a weather event that will bring slippery conditions.

When salt must be used, use a minimum amount or substitute a salt other than sodium chloride. Calcium chloride, for instance, is a salt that is only a tenth as toxic to plants as sodium chloride. One of the best materials as far as effectiveness with minimum damage to vehicles, concrete, and vegetation, is calcium magnesium acetate (CMA); but it’s expensive.

Salts that are fertilizers, such as ammonium nitrate or calcium nitrate, melt ice and at the same time nourish plants. Salts other than sodium chloride still need to be used with caution, for they can cause salt desiccation and/or nutrient imbalances in plants.Spreading woodashMy favorite treatment for icy conditions here at home is spreading wood ash. Effectiveness comes from the dark color absorbing sunlight to speed melting, a slight grittiness increasing traction, and its salt content. Of course, access to wood ash means you or an ash-rich friend burns wood for heat. 

For all its benefits, wood ash is a mess if tracked indoors. I take off my shoes or boots in the mudroom.


Calamity Avoidance

A horticultural calamity averted. Again. Deb was snipping some leaves from our potted rosemary “tree” for salad dressing and said she noticed that the plant looked a little wilty. I was skeptical. Rosemary leaves are so narrow and stiff that they hardly broadcast their thirst. Still, quite a few rosemary plants have succumbed to winter drought here.Potted rosemary tree in winter

I checked the plant and, in fact, the leaves did look a bit wilty. The probe of my sort-of-accurate electronic moisture tester (which I nonetheless highly recommend) confirmed Deb’s diagnosis. The soil was very dry but, luckily, not to the point of killing the plant.

Allow me to digress . . . Soil scientists represent soil moisture levels with four descriptors. Right after a thorough watering, a soil is “saturated,” with all pores filled with water. Saturation is not desirable in the long term because roots need to “breathe” to do their work of drawing in nutrients and water, which is why plants exhibit the same symptoms from either dry or sodden soil.

Without additional water, gravity begins to pull water down and out of the larger pores of a saturated soil. Once gravity has pulled all the water it can from a soil, the soil is at “field capacity,” much to the pleasure of resident plants. At this point, large pores are filled with air yet some water, which is available for plants, is retained within smaller pores and clinging to soil particles.

Roots continue to slurp more and more water from the soil, but with increasing difficulty because water within even smaller pores and clinging even closer to soil particles is increasingly tightly held there by capillary attraction. Although the soil has moisture, it’s mostly inaccessible to plants. “Wilting point” has been reached.

Eventually, the only moisture left in the soil is that held very tightly in the very smallest pores and pressed tight against soil particles. That’s “permanent wilting point” from which, as the name implies, there’s no turning back. The plant will die.

The actual amount of water in a soil at any of these stages depends on the range of particle sizes in the soil. Clay soils have tiny particles, with tiny spaces between them, so have more water at wilting and permanent wilting point than do sandy soils, with their large particles and large pores.

Soil water vs. particle size

At or near field capacity, sands have more air and less water than clays.

Where were we? Oh, my rosemary plant. I’m figuring it was just teetering on the edge of wilting point. Needless to say, I watered both my rosemary “trees.”

(For a lot more about soil water and how to make the best of it, see my book The Ever Curious Gardener: Using a Little Natural Science for a Much Better Garden.)

Dry Air, Moist (Enough) Soil

You’d think — I once did — that rosemary, because in the wild it billows down dry hillsides overlooking the Mediterranean, would be resistant to drought. It does tolerate dry air. But those wild plants’ roots are in the ground where they can forage far and wide for moisture; not so in a pot.

Also, my rosemary plants are coddled with relatively consistent warmth in winter and a potting mix rich in nutrients. Couple this with low light conditions, even near a south-facing window, and you get very succulent growth. I don’t know what rosemary plants growing on a Grecian hillside are doing now, but my plants are growing like gangbusters. All that succulent growth transpires lots of water, and is very susceptible to drought.

Rosemary, half survived

Left half of this rosemary expired last summer

Once my plants go outdoors in summer, their leaves mature and toughen and growth is less succulent. They do still need sufficient moisture, so I have drip tubes on a timer quenching their thirst (and that of other plants). Except, that is, when the timer’s battery needs replacing and I don’t notice it. That was last summer. The plants were not at the permanent wilting point but a number of branches, which I pruned off, dried up, dead.

In Praise of Potted Rosemary

All this is not to frown upon growing rosemary where it can’t survive winters outdoors. On the contrary, I consider rosemary to be the finest herb for indoor growing. Flavorwise, it packs a powerful punch, unlike chives, for example, a plant that needs to be practically decimated if you really want to flavor something with it. Merely brushing against my rosemary plant releases an aromatic, piney cloud.

Rosemary is also a very attractive houseplant whether grown as a scraggly shrub reminiscent of the wild plants in their native haunts, trained as dense cones, or — as are my plants — as miniature trees. The leaves retain a healthy, verdant look, unlike those of basil, which look sickly and out of their element in dry, relatively dark and cool homes in winter.

Rosemary also rarely suffers from any insect or disease problem.

And finally, properly cared for, rosemary is perennial so can provide aroma, flavor, and beauty   for many, many years.

But you and I do need to pay close attention to watering.

standard bay, rosemary, citrus

Rosemary, with its compatriots, bay and citrus, in summer


Feed Sooner, Not later

Although shoot growth of woody plants ground to a halt weeks ago, root growth will continue until soil temperatures drop below about 40 degrees Fahrenheit. Root and shoot growth of woody plants and lawn grass are asynchronous, with root growth at a maximum in early spring and fall, and shoot growth at a maximum in summer. So roots aren’t just barely growing this time of year; they’re growing more vigorously than in midsummer. 

Compost mulch on pearsRemember the song lyrics: “House built on a weak foundation will not stand, no, no”? Well, the same goes for plants. (Plant with a weak root system will not be healthy, no, no.) Fertilization in the fall, rather than in winter, spring, or summer, promotes strong root systems in plants.

By the time a fertilizer applied in late winter or early spring gets into a plant, shoots are building up steam and need to be fed. Fertilization in summer forces succulent shoot growth late in the season, and this type of growth is susceptible to damage from ensuing cold.

They Hunger For . . . 

The nutrient plants are most hungry for is nitrogen. But nitrogen is also the most evanescent of nutrients in the soil, subject to leaching down through the soil by rainwater or floating off into the air as a gas. The goal is to apply nitrogen so that it can be taken up by plants in the fall, with some left over to remain in the soil through winter and be in place for plant use next spring. 

Two conditions foster nitrogen loss as gas. The first is a waterlogged soil. If you’re growing most cultivated plants — yellow flag iris, marsh marigold, rice, and cranberry are some exceptions — your soil should not be waterlogged, aside from considerations about nitrogen. (Roots need to breathe in order to function.) Nitrogen also evaporates from manure that is left exposed to sun and wind on top of the soil. Manure either should be dug into the soil right after spreading, or composted, after which it can be spread on top of the soil, or dug in.

Leaching of nitrogen fertilizer is a more common and serious problem, especially on sandy soils. The way to prevent leaching is to apply a form of nitrogen that either is not readily soluble, or that clings to the soil particles. Most chemical fertilizers — whether from a bag of 10-10-10, 5-10-10, or any other formulation — are soluble, although a few are specially formulated to release nitrogen slowly.

Fertilizer labelThe two major forms of soluble nitrogen that plants can “eat” are nitrate nitrogen and ammonium nitrogen. Nitrate nitrogen will wash right through the soil; ammonium nitrogen, because it has a positive charge, can be grabbed and held onto negatively charged soil particles. Therefore, if you’re going to purchase a chemical fertilizer to apply in the fall, always buy a type that is high in ammonium nitrogen. The forms of nitrogen in a fertilizer bag are spelled out right on its label.

Go Organic

Rather than wade through the chemical jargon, nitrogen loss through the winter can be averted by using an organic nitrogen fertilizer. Nitrogen in such fertilizers, with the exception of blood meal, is locked up and held in an insoluble form. As soil microbes solubilize the nitrogen locked up in organic fertilizers, it is released first as ammonium nitrogen. So by using an organic nitrogen source, the nitrogen is not soluble to begin with, and when it becomes soluble through the action of microbes, it’s in a form that clings to the soil particles and not wash out of the soil.Organic fertilizers

(Except in very acidic soils, other soil microbes then go on to convert ammonium nitrogen to nitrate nitrogen. This reaction screeches almost to a standstill at temperatures below 50 degrees Fahrenheit, so the ammonium nitrogen can just sit there, clinging to soil particles, until roots reawaken in late winter or early spring.)

Common sources of organic nitrogen include soybean meal, cottonseed meal, fish meal, and manure. Hoof and horn meal, leather dust, feather dust, and hair are esoteric sources, though plants will make use of them as if they were just ordinary, organic fertilizers. Even organic mulches, such as wood chips, straw, and leaves, will nourish the ground as they decompose over time.Fertilizer application Woor chip mulching

The Cadillac of fertilizers is compost. Compost offers a slew of nutrients, in addition to nitrogen, released slowly into the soil as microbes work away on it. Compost — most organic fertilizers, in fact — are not the ticket for a starving plant that needs a quick fix of food.Compost bins

Every year I spread compost an inch deep beneath especially hungry plants like vegetables and young trees and shrubs to keep them well fed. Less hungry plants get one of the above-mentioned organic mulches. The benefits of these applications continue, trailing off, for a few years, so annual applications build up continual reserves of soil nutrients, doled out by soil microbes, that translate to healthy plants and soil.Composted garden beds
(More details about fertilization can be found in my book Weedless Gardening.)


Soil That is Too Good?

 I don’t expect to elicit much sympathy from moaning about the problem with my soil here on the farmden; the problem is that it’s too good. Wait! Don’t roll your eyes or, worse, stop reading. Allow me to present my case.
Aerial view of farmden
The setting: A valley cut through with a small river (the Wallkill River) in New York’s Hudson Valley. River bottom soil, specifically young alluvial soil, rich in nutrients, a silty clay loam with perfect drainage. Also naturally rich in nutrients. No rocks.

So what’s the problem? One problem is too much growth from plants that I’m not cultivating — weeds, everything from stilt grass and garlic mustard to wild blackberries and poison ivy to ash and cherry trees. Every minute of every day they are making the most of this rich ground and trying to insinuate themselves into my plantings. They creep into the edges of the vegetable gardens, settling in especially well right at the bottom of any fencing, where they are hard to weed out. 

My land is backed by forest running up to hills, then mountains, with soil that’s pretty much the opposite of what I have down here in the valley. It feels like that forest is just waiting for me to let up weeding and mowing, ready to spring down here and engulf my plantings.

That feeling is pretty much borne out in the one-third of an acre meadow to the south. Once a year mowing keeps the meadow a meadow. Yet even in the few months of each growing season, joe-pye-weed and ragweed stand almost 9 feet high and goldenrod, monarda, and grasses grow densely.

Looking at the herbage more closely I see multiflora rose, staghorn sumac, grapevines, and other woody plants elbowing their ways in here and there. And cherry, red maple, red oak, and poplar trees keep trying to introduce their progeny into the meadow to morph it into forest. Which isn’t a bad thing except that I scythe parts of that meadow for harvesting the herbage, not woody plants, to feed my compost, and grow apples, kiwis, pawpaws, hazelnuts, and other fruits and nuts that I cultivate in and around the meadow.

Errant and Robust

Even some cultivated plants grow a bit too well here.

Crocosmia, for example.  Towards the end of summer, this South African, summer-flowering bulb sprouts a tall, thin flower shoot about four feet high. The shoot curves over and then fire-engine red flowers open sequentially along the upper portion of the curve.
Crocosmia up close
Many years ago I planted crocosmia here and, as directed, dug the corms up at the end of the season for winter storage, just as I would do for dahlias. Those first few seasons, the plants hardly bloomed before frost killed the tops.

Long story short is that the original planting, which has since grown to a clump of plants, now blooms reliably each August, and does so without my having to ever dig the corms up for winter. Good so far, except that the plant evidently also now ripens seeds, and these seeds find their way elsewhere on the property. That would not be so bad except that in this rich soil one little seedling soon multiplies into a clump of vigorous plants that can threaten the existence of other plants.
My tack in reining in crocosmia is lopping off all spent flower heads wherever I spot them with a hedge shears, and digging out seedlings where they are not wanted.

This summer I even noticed a crocosmia seedling in the meadow. Hmmm. I recently saw, in a video documentary about color in the natural world (Life in Color with David Attenborough, highly recommended), a field of crocosmia in its native habitat, the flowers hovering over the field like a red mist. Do I want that in my meadow? Should I transplant some corms there? Would my rich soil and the apparent footloose habit of crocosmia create a future nightmare? If so, could I awaken from that nightmare with one whole season of mowing that portion of the field? Grasses are pretty much the only plants that tolerate repeated mowing.

Permaculture Ideals

All this is part of the reason I wince when I’m accused of practicing permaculture (although my agricultural perspective and much of what I do does happen to align with those of permies). Permaculture’s origins are in the poor soils and dry climate of Australia. Plant a tree there, give it water, nutrients, mulch, and you’re not inviting half the plant world in as too-close neighbors. But try this here on my farmden — or in any other place with hot summers and sufficient natural rainfall — and those “neighbors” will be at the door.

Even among cultivated plants grown cheek to jowl in the various “guilds,” growth eventually becomes so rampant that it’s a major job to keep growth among plants balanced so each plant gets what it needs in terms of light and air.

Most permaculture sites outside of climates such as Australia, our Southwest, and the Mediterranean, that I have seen mingle plants nicely on paper and look good when first planted. After a few years, though, they become a tangled mess of plants with low yields of poor-quality fruits and vegetables.

Permaculture seems to encompass a broad philosophy, broad enough so a well-known local permaculturalist once told me, contrary to my opinion, that I was practicing permaculture. I asked him, “Ok, then; what isn’t permaculture?” He replied, “Everything is permaculture! (Except commercial agriculture).”

All this is not to say that I don’t side with permaculturalists in certain key practices. Like them, I minimize soil disturbance. I also practice interplanting, such as the blackcurrants and pawpaws, favor pest resistant species, such as hardy kiwifruit and gooseberries, and let my ducks have almost free rein here. I also have my requisite shiitake logs, fire wood pile, and solar cells.