ORGANIC GARDENER'S COMPOSTING TEXT

core and the core becomes the skin. This way, any fly larvae, pathogens, or insect eggs that might not be killed by the cooler temperatures on the outside are rotated into the lethal high heat of the core every few days. The speed of the U.C. method also appeals to the backyard gardener. At home, frequent turning can be accomplished either in naked heaps, or by switching from one bin to the next and back, or with a compost tumbler. But a chipper/shredder is also essential. Grinding everything that goes into the heap has other advantages than higher heat and accelerated processing. Materials may be initially mixed as they are ground and small particles are much easier to turn over than long twigs, tough straw, and other fibrous materials that tie the heap together and make it difficult to separate and handle with hand tools. Backyard shredders have other uses, especially for gardeners with no land to waste. Composting tough materials like grape prunings, berry canes, and hedge trimmings can take a long time. Slow heaps containing resistant materials occupy precious space. With a shredder you can fast-compost small limbs, tree prunings, and other woody materials like corn and sunflower stalks. Whole autumn leaves tend to compact into airless layers and decompose slowly, but dry leaves are among the easiest of all materials to grind. Once smashed into flakes, leaves become a fluffy material that resists compaction. Electric driven garden chipper/shredders are easier on the neighbors' ears than more powerful gasoline-powered machines, although not so quiet that I'd run one without ear protection. Electrics are light enough for a strong person to pick up and carry out to the composting area and keep secured in a storeroom. One more plus, there never is any problem starting an electric motor. But no way to conveniently repair one either. There are two basic shredding systems. One is the hammermill--a grinding chamber containing a rotating spindle with steel tines or hammers attached that repeatedly beats and tears materials into smaller and smaller pieces until they fall out through a bottom screen. Hammermills will flail almost anything to pieces without becoming dulled. Soft, green materials are beaten to shreds; hard, dry, brittle stuff is rapidly fractured into tiny chips. Changing the size of the discharge screen adjusts the size of the final product. By using very coarse screens, even soft, wet, stringy materials can be slowly fed through the grinding chamber without hopelessly tangling up in the hammers. Like a coarse power planer in a wood shop, the other type of machine uses sharpened blades that slice thin chips from whatever is pushed into its maw. The chipper is designed to grind woody materials like small tree limbs, prunings, and berry canes. Proper functioning depends on having sharp blades. But edges easily become dulled and require maintenance. Care must be taken to avoid passing soil and small stones through a chipper. Soft, dry, brittle materials like leaves will be broken up but aren't processed as rapidly as in a hammermill. Chippers won't handle soft wet stuff. When driven by low horsepower electric motors, both chippers and hammermills are light-duty machines. They may be a little shaky, standing on spindly legs or small platforms, so materials must be fed in gently. Most electric models cost between $300 and $400. People with more than a postage-stamp yard who like dealing with machinery may want a gasoline-powered shredder/chipper. These are much more substantial machines that combine both a big hammermill shredder with a side-feeding chipper for limbs and branches. Flailing within a hammermill or chipping limbs of two or more inches in diameter focuses a great deal of force; between the engine noise and the deafening din as dry materials bang around the grinding chamber, ear protection is essential. So are safety goggles and heavy gloves. Even though the fan belt driving the spindle is shielded, I would not operate one without wearing tight-fitting clothes. When grinding dry materials, great clouds of dust may be given off. Some of these particles, like the dust from alfalfa or from dried-out spoiled (moldy) hay, can severely irritate lungs, eyes, throat and nasal passages. A face mask, or better, an army surplus gas mask with built-in goggles, may be in order. And you'll probably want to take a shower when finished. Fitted with the right-size screen selected from the assortment supplied at purchase, something learned after a bit of experience, powerful hammermills are capable of pulverizing fairly large amounts of dry material in short order. But wet stuff is much slower to pass through and may take a much coarser screen to get out at all. Changing materials may mean changing screens and that takes a few minutes. Dry leaves seem to flow through as fast as they can be fed in. The side-feed auxiliary chippers incorporated into hammermills will make short work of smaller green tree limbs; but dry, hardened wood takes a lot longer. Feeding large hard branches too fast can tear up chipper blades and even break the ball-bearing housings holding the spindle. Here I speak from experience. Though advertisements for these machines make them seem effortless and fast, shredders actually take considerable time, energy, skilled attention, constant concentration, and experience. When grinding one must attentively match the inflow to the rate of outflow because if the hopper is overfilled the tines become snarled and cease to work. For example, tangling easily can occur while rapidly feeding in thin brittle flakes of dry spoiled hay and then failing to slow down while a soft, wet flake is gradually reduced. To clear a snarled rotor without risking continued attachment of one's own arm, the motor must be killed before reaching into the hopper and untangling the tines. To clear badly clogged machines it may also be necessary to first remove and then replace the discharge screen, something that takes a few minutes. There are significant differences in the quality of materials and workmanship that go into making these machines. They all look good when freshly painted; it is not always possible to know what you have bought until a season or two of heavy use has passed. One tried-and-true aid to choosing quality is to ask equipment rental businesses what brand their customers are not able to destroy. Another guide is to observe the brand of gasoline engine attached. In my gardening career I've owned quite a few gas-powered rotary tillers and lawnmowers and one eight-horsepower shredder. In my experience there are two grades of small gasoline engines--"consumer" and the genuine "industrial." Like all consumer merchandise, consumer-grade engines are intended to be consumed. They have a design life of a few hundred hours and then are worn out. Most parts are made of soft, easily-machined aluminum, reinforced with small amounts of steel in vital places. There are two genuinely superior American companies--Kohler and Wisconsin-that make very durable, long-lasting gas engines commonly found on small industrial equipment. With proper maintenance their machines are designed to endure thousands of hours of continuous use. I believe small gas engines made by Yamaha, Kawasaki, and especially Honda, are of equal or greater quality to anything made in America. I suggest you could do worse than to judge how long the maker expects their shredder/chipper to last by the motor it selects. Gasoline-powered shredder/chippers cost from $700 to $1,300. Back in the early 1970s I wore one pretty well out in only one year of making fast compost for a half-acre Biodynamic French intensive market garden. When I amortized the cost of the machine into the value of both the compost and the vegetables I grew with the compost, and considered the amount of time I spent running the grinder against the extra energy it takes to turn ordinary slow compost heaps I decided I would be better off allowing my heaps to take more time to mature. Sheet Composting Decomposition happens rapidly in a hot compost heap with the main agents of decay being heat-loving microorganisms. Decomposition happens slowly at the soil's surface with the main agents of decay being soil animals. However, if the leaves and forest duff on the floor of a forest or a thick matted sod are tilled into the topsoil, decomposition is greatly accelerated. For two centuries, frontier American agriculture depended on just such a method. Early pioneers would move into an untouched region, clear the forest, and plow in millennia of accumulated nutrients held as biomass on the forest floor. For a few years, perhaps a decade, or even twenty years if the soil carried a higher level of mineralization than the average, crops from forest soils grew magnificently. Then, unless other methods were introduced to rebuild fertility, yields, crop, animal, and human health all declined. When the less-leached grassy prairies of what we now call the Midwest were reached, even greater bounties were mined out for more years because rich black-soil grasslands contain more mineral nutrients and sod accumulates far more humus than do forests. Sheet composting mimics this system while saving a great deal of effort. Instead of first heaping organic matter up, turning it several times, carting humus back to the garden, spreading it, and tilling it in, sheet composting conducts the decomposition process with far less effort right in the soil needing enrichment. Sheet composting is the easiest method of all. However, the method has certain liabilities. Unless the material being spread is pure manure without significant amounts of bedding, or only fresh spring grass clippings, or alfalfa hay, the carbon-nitrogen ratio will almost certainly be well above that of stable humus. As explained earlier, during the initial stages of decay the soil will be thoroughly depleted of nutrients. Only after the surplus carbon has been consumed will the soil ecology and nutrient profile normalize. The time this will take depends on the nature of the materials being composted and on soil conditions. If the soil is moist, airy, and warm and if it already contained high levels of nutrients, and if the organic materials are not ligninous and tough and have a reasonable C/N, then sheet composting will proceed rapidly. If the soil is cold, dry, clayey (relatively airless) or infertile and/or the organic matter consists of things like grain straw, paper, or the very worst, barkless sawdust, then decomposition will be slowed. Obviously, it is not possible to state with any precision how fast sheet composting would proceed for you. Autumn leaves usually sheet compost very successfully. These are gathered, spread over all of the garden (except for those areas intended for early spring sowing), and tilled in as shallowly as possible before winter. Even in the North where soil freezes solid for months, some decomposition will occur in autumn and then in spring, as the soil warms, composting instantly resumes and is finished by the time frost danger is over. Sheet composting higher C/N materials in spring is also workable where the land is not scheduled for planting early. If the organic matter has a low C/N, like manure, a tender green manure crop not yet forming seed, alfalfa hay or grass clippings, quite a large volume of material can be decomposed by warm soil in a matter of weeks. However, rotting large quantities of very resistant material like sawdust can take many months, even in hot, moist soil. Most gardeners cannot afford to give their valuable land over to being a compost factory for months. One way to speed the sheet composting of something with a high C/N is to amend it with a strong nitrogen source like chicken manure or seed meal. If sawdust is the only organic matter you can find, I recommend an exception to avoiding chemical fertilizer. By adding about 80 pounds of urea to each cubic yard of sawdust, its overall C/N is reduced from 500:1 to about 20:1. Urea is perhaps the most benign of all chemical nitrogen sources. It does not acidify the soil, is not toxic to worms or other soil animals or microorganisms, and is actually a synthetic form of the naturally occurring chemical that contains most of the nitrogen in animal urine. In that sense, putting urea in soil is not that different than putting synthetic vitamin C in a human body Burying kitchen garbage is a traditional form of sheet composting practiced by row-cropping gardeners usually in mild climates where the soil does not freeze in winter. Some people use a post hole digger to make a neat six-to eight-inch diameter hole about eighteen inches deep between well-spaced growing rows of plants. When the hole has been filled to within two or three inches of the surface, it is topped off with soil. Rarely will animals molest buried garbage, it is safe from flies and yet enough air exists in the soil for it to rapidly decompose. The local soil ecology and nutrient balance is temporarily disrupted, but the upset only happens in this one little spot far enough away from growing plants to have no harmful effect. Another garbage disposal variation has been called "trench composting." Instead of a post hole, a long trench about the width of a combination shovel and a foot deep is gradually dug between row crops spaced about four feet (or more) apart. As bucket after bucket of garbage, manure, and other organic matter are emptied into the trench, it is covered with soil dug from a little further along. Next year, the rows are shifted two feet over so that crops are sown above the composted garbage. Mulch Gardening Ruth Stout discovered--or at least popularized this new-to-her method. Mulching may owe some of its popularity to Ruth's possession of writing talent similar to her brother Rex's, who was a well-known mid-century mystery writer. Ruth's humorous book, _Gardening Without Work_ is a fun-to-read classic that I highly recommend if for no other reason than it shows how an intelligent person can make remarkable discoveries simply by observing the obvious. However, like many other garden writers, Ruth Stout made the mistake of assuming that what worked in her own backyard would be universally applicable. Mulch gardening does not succeed everywhere. This easy method mimics decomposition on the forest floor. Instead of making compost heaps or sheet composting, the garden is kept thickly covered with a permanent layer of decomposing vegetation. Year-round mulch produces a number of synergistic advantages. Decay on the soil's surface is slow but steady and maintains fertility. As on the forest floor, soil animals and worm populations are high. Their activities continuously loosen the earth, steadily transport humus and nutrients deeper into the soil, and eliminate all need for tillage. Protected from the sun, the surface layers of soil do not dry out so shallow-feeding species like lettuce and moisture-lovers like radishes make much better growth. During high summer, mulched ground does not become unhealthfully heated up either. The advantages go on. The very top layer of soil directly under the mulch has a high organic matter content, retaining moisture, eliminating crusting, and consequently, enhancing the germination of seeds. Mulchers usually sow in well-separated rows. The gardener merely rakes back the mulch and exposes a few inches of bare soil, scratches a furrow, and covers the seed with humusy topsoil. As the seedlings grow taller and are thinned out, the mulch is gradually pushed back around them. Weeds? No problem! Except where germinating seeds, the mulch layer is thick enough to prevent weed seeds from sprouting. Should a weed begin showing through the mulch, this is taken as an indication that spot has become too thinly covered and a flake of spoiled hay or other vegetation is tossed on the unwanted plant, smothering it. Oh, how easy it seems! Pick a garden site. If you have a year to wait before starting your garden do not even bother to till first. Cover it a foot deep with combinations of spoiled hay, leaves, grass clippings, and straw. Woody wastes are not suitable because they won't rot fast enough to feed the soil. Kitchen garbage and manures can also be tossed on the earth and, for a sense of tidiness, covered with hay. The mulch smothers the grass or weeds growing there and the site begins to soften. Next year it will be ready to grow vegetables. If the plot is very infertile to begin with there won't be enough biological activity or nutrients in the soil to rapidly decompose the mulch. In that case, to accelerate the process, before first putting down mulch till in an initial manure layer or a heavy sprinkling of seed meal. Forever after, mulching materials alone will be sufficient. Never again till. Never again weed. Never again fertilize. No compost piles to make, turn, and haul. Just keep your eye open for spoiled hay and buy a few inexpensive tons of it each year. Stout, who discovered mulch gardening in Connecticut where irregular summer rains were usually sufficient to water a widely-spaced garden, also mistakenly thought that mulched gardens lost less soil moisture because the earth was protected from the drying sun and thus did not need irrigation through occasional drought. I suspect that drought resistance under mulch has more to do with a plant's ability to feed vigorously, obtain nutrition, and continue growing because the surface inches where most of soil nutrients and biological activities are located, stayed moist. I also suspect that actual, measurable moisture loss from mulched soil may be greater than from bare earth. But that's another book I wrote, called _Gardening Without Irrigation. _ Yes, gardening under permanent year-round mulch seems easy, but it does have a few glitches. Ruth Stout did not discover them because she lived in Connecticut where the soil freezes solid every winter and stays frozen for long enough to set back population levels of certain soil animals. In the North, earwigs and sow bugs (pill bugs) are frequently found in mulched gardens but they do not become a serious pest. Slugs are infrequent and snails don't exist. All thanks to winter. Try permanent mulch in the deep South, or California where I was first disappointed with mulching, or the Maritime northwest where I now live, and a catastrophe develops. During the first year these soil animals are present but cause no problem. But after the first mild winter with no population setback, they become a plague. Slugs (and in California, snails) will be found everywhere, devastating seedlings. Earwigs and sow bugs, that previously only were seen eating only decaying mulch, begin to attack plants. It soon becomes impossible to get a stand of seedlings established. The situation can be rapidly cured by raking up all the mulch, carting it away from the garden, and composting it. I know this to be the truth because I've had to do just that both in California where as a novice gardener I had my first mulch catastrophes, and then when I moved to Oregon, I gave mulching another trial with similar sad results. Sources for Composters, Grinders and etc. _ Shredder/Chippers and other power equipment_ I've been watching this market change rapidly since the early 1970s. Manufacturers come and go. Equipment is usually ordered direct from the maker, freight extra. Those interested in large horsepower shredder/chippers might check the advertisements in garden-related magazines such as _National Gardening, Organic Gardening, Sunset, Horticulture, Fine Gardening, Country Living (Harrowsmith), _etc. Without intending any endorsement or criticism of their products, two makers that have remained in business since I started gardening are: Kemp Company. 160 Koser Road., Lititz, PA 17543. (also compost drums)