ORGANIC GARDENER'S COMPOSTING TEXT

nutritional value of crops have repeatedly remarked that the best crops are grown with compost and fertilizer. Not fertilizer alone and not compost alone. The best place for gardeners to see these data is Werner Schupan's book (listed in the bibliography). But say the word "fertilizer" to an organic gardener and you'll usually raise their hackles. Actually there is no direct linkage of the words "fertilizer" and "chemical." A fertilizer is any concentrated plant nutrient source that rapidly becomes available in the soil. In my opinion, chemicals are the poorest fertilizers; organic fertilizers are far superior. The very first fertilizer sold widely in the industrial world was guano. It is the naturally sun-dried droppings of nesting sea birds that accumulates in thick layers on rocky islands off the coast of South America. Guano is a potent nutrient source similar to dried chicken manure, containing large quantities of nitrogen, fair amounts of phosphorus, and smaller quantities of potassium. Guano is more potent than any other manure because sea birds eat ocean fish, a very high protein and highly mineralized food. Other potent organic fertilizers include seed meals; pure, dried chicken manure; slaughterhouse wastes; dried kelp and other seaweeds; and fish meal. Composition of Organic Fertilizers Material % Nitrogen % Phos. % Potassium Alfalfa meal 2.5 0.5 2.1 Bone meal (raw) 3.5 21.0 0.2 Bone meal (steamed) 2.0 21.0 0.2 Chicken manure (pure, fresh) 2.6 1.25 0.75 Cottonseed meal 7.0 3.0 2.0 Blood meal 12.0 3.0 -- Fish meal 8.0 7.0 -- Greensand -- 1.5 7.0 Hoof and Horn 12.5 2.0 -- Kelp meal 1.5 0.75 4.9 Peanut meal 3.6 0.7 0.5 Tankage 11.0 5.0 -- Growing most types of vegetables requires building a level of soil fertility that is much higher than required by field crops like cereals, soybeans, cotton and sunflowers. Field crops can be acceptably productive on ordinary soils without fertilization. However, because we have managed our farm soils as depreciating industrial assets rather than as relatively immortal living bodies, their ability to deliver plant nutrients has declined and the average farmer usually must add additional nutrients in the form of concentrated, rapidly-releasing fertilizers if they are going to grow a profitable crop. Vegetables are much more demanding than field crops. They have long been adapted to growing on potent composts or strong manures like fresh horse manure or chicken manure. Planted and nourished like wheat, most would refuse to grow or if they did survive in a wheat field, vegetables would not produce the succulent, tender parts we consider valuable. Building higher than normal levels of plant nutrients can be done with large additions of potent compost and manure. In semi-arid parts of the country where vegetation holds a beneficial ratio of calcium to potassium food grown that way will be quite nutritious. In areas of heavier rainfall, increasing soil fertility to vegetable levels is accomplished better with fertilizers. The data in the previous section gives strong reasons for many gardeners to limit the addition of organic matter in soil to a level that maintains a healthy soil ecology and acceptable tilth. Instead of supplementing compost with low quality chemical fertilizers, I recommend making and using a complete organic fertilizer mix to increase mineral fertility. Making and Using Complete Organic Fertilizer The basic ingredients used for making balanced organic fertilizers can vary and what you decide on will largely depend on where you live. Seed meal usually forms the body of the blend. Seed meals are high in nitrogen and moderately rich in phosphorus because plants concentrate most of the phosphorus they collect during their entire growth cycle into their seeds to serve to give the next generation a strong start. Seed meals contain low but more than adequate amounts of potassium. The first mineral to be removed by leaching is calcium. Adding lime can make all the difference in wet soils. Dolomite lime also adds magnesium and is the preferable form of lime to use in a fertilizer blend on most soils. Gypsum could be substituted for lime in arid areas where the soils are naturally alkaline but still may benefit from additional calcium. Kelp meal contains valuable trace minerals. If I were short of money, first I'd eliminate the kelp meal, then the phosphate source. All ingredients going into this formula are measured by volume and the measurements can be very rough: by sack, by scoop, or by coffee can. You can keep the ingredients separated and mix fertilizer by the bucketful as needed or you can dump the contents of half a dozen assorted sacks out on a concrete sidewalk or driveway and blend them with a shovel and then store the mixture in garbage cans or even in the original sacks the ingredients came in. This is my formula. 4 parts by volume: Any seed meal such as cottonseed meal, soybean meal, sunflower meal, canola meal, linseed meal, safflower, peanut meal or coconut meal. Gardeners with deep pocketbooks and insensitive noses can also fish meal. Gardeners without vegetarian scruples may use meat meal, tankage, leather dust, feather meal or other slaughterhouse waste. 1 part by volume: Bone meal or rock phosphate 1 part by volume: Lime, preferably dolomite on most soils. (Soils derived from serpentine rock contain almost toxic levels of magnesium and should not receive dolomite. Alkaline soils may still benefit from additional calcium and should get gypsum instead of ordinary lime.) 1/2 part by volume: kelp meal or other dried seaweed. To use this fertilizer, broadcast and work in about one gallon per each 100 square feet of growing bed or 50 feet of row. This is enough for all low-demand vegetables like carrots, beans and peas. For more needy species, blend an additional handful or two into about a gallon of soil below the transplants or in the hill. If planting in rows, cut a deep furrow, sprinkle in about one pint of fertilizer per 10-15 row feet, cover the fertilizer with soil and then cut another furrow to sow the seeds in about two inches away. Locating concentrations of nutrition close to seeds or seedlings is called "banding." I have a thick file of letters thanking me for suggesting the use of this fertilizer blend. If you've been "building up your soil" for years, or if your vegetables never seem to grow as large or lustily as you imagine they should, I strongly suggest you experiment with a small batch of this mixture. Wouldn't you like heads of broccoli that were 8-12 inches in diameter? Or zucchini plants that didn't quit yielding? CHAPTER NINE Making Superior Compost The potency of composts can vary greatly. Most municipal solid waste compost has a high carbon to nitrogen ratio and when tilled into soil temporarily provokes the opposite of a good growth response until soil animals and microorganisms consume most of the undigested paper. But if low-grade compost is used as a surface mulch on ornamentals, the results are usually quite satisfactory even if unspectacular. If the aim of your own composting is to conveniently dispose of yard waste and kitchen garbage, the information in the first half of the book is all you need to know. If you need compost to make something that dependably GROWS plants like it was fertilizer, then this chapter is for you. A Little History Before the twentieth century, the fertilizers market gardeners used were potent manures and composts. The vegetable gardens of country folk also received the best manures and composts available while the field crops got the rest. So I've learned a great deal from old farming and market gardening literature about using animal manures. In previous centuries, farmers classified manures by type and purity. There was "long" and "short" manure, and then, there was the supreme plant growth stimulant, chicken manure. Chicken manure was always highly prized but usually in short supply because preindustrial fowl weren't caged in factories or permanently locked in hen houses and fed scientifically formulated mixes. The chicken breed of that era was usually some type of bantam, half-wild, broody, protective of chicks, and capable of foraging. A typical pre-1900 small-scale chicken management system was to allow the flock free access to hunt their own meals in the barnyard and orchard, luring them into the coop at dusk with a bit of grain where they were protected from predators while sleeping helplessly. Some manure was collected from the hen house but most of it was dropped where it could not be gathered. The daily egg hunt was worth it because, before the era of pesticides, having chickens range through the orchard greatly reduced problems with insects in fruit. The high potency of chicken manure derives from the chickens' low C/N diet: worms, insects, tender shoots of new grass, and other proteinaceous young greens and seeds. Twentieth-century chickens "living" in egg and meat factories must still be fed low C/N foods, primarily grains, and their manure is still potent. But anyone who has savored real free-range eggs with deep orange yokes from chickens on a proper diet cannot be happy with what passes for "eggs" these days. Fertilizing with pure chicken manure is not very different than using ground cereal grains or seed meals. It is so concentrated that it might burn plant leaves like chemical fertilizer does and must be applied sparingly to soil. It provokes a marked and vigorous growth response. Two or three gallons of dry, pure fresh chicken manure are sufficient nutrition to GROW about 100 square feet of vegetables in raised beds to the maximum. Exclusively incorporating pure chicken manure into a vegetable garden also results in rapid humus loss, just as though chemical fertilizers were used. Any fertilizing substance with a C/N below that of stabilized humus, be it a chemical or a natural substance, accelerates the decline in soil organic matter. That is because nitrate nitrogen, the key to constructing all protein, is usually the main factor limiting the population of soil microorganisms. When the nitrate level of soil is significantly increased, microbe populations increase proportionately and proceeds to eat organic matter at an accelerated rate. That is why small amounts of chemical fertilizer applied to soil that still contains a reasonable amount of humus has such a powerful effect. Not only does the fertilizer itself stimulate the growth of plants, but fertilizer increases the microbial population. More microbes accelerate the breakdown of humus and even more plant nutrients are released as organic matter decays. And that is why holistic farmers and gardeners mistakenly criticize chemical fertilizers as being directly destructive of soil microbes. Actually, all fertilizers, chemical or organic, _indirectly_ harm soil life, first increasing their populations to unsustainable levels that drop off markedly once enough organic matter has been eaten. Unless, of course, the organic matter is replaced. Chicken manure compost is another matter. Mix the pure manure with straw, sawdust, or other bedding, compost it and, depending on the amount and quantity of bedding used and the time allowed for decomposition to occur, the resultant C/N will be around 12:1 or above. Any ripened compost around 12:1 still will GROW plants beautifully. Performance drops off as the C/N increases. Since chicken manure was scarce, most pre-twentieth century market gardeners depended on seemingly unlimited supplies of "short manure," generally from horses. The difference between the "long" and the "short" manure was bedding. Long manure contained straw from the stall while short manure was pure street sweepings without adulterants. Hopefully, the straw portion of long manure had absorbed a quantity of urine. People of that era knew the fine points of hay quality as well as people today know their gasoline. Horses expected to do a day's work were fed on grass or grass/clover mixes that had been cut and dried while they still had a high protein content. Leafy hay was highly prized while hay that upon close inspection revealed lots of stems and seed heads would be rejected by a smart buyer. The working horse's diet was supplemented with a daily ration of grain. Consequently, uncomposted fresh short manure probably started out with a C/N around 15:1. However, don't count on anything that good from horses these days. Most horses aren't worked daily so their fodder is often poor. Judging from the stemmy, cut-too-late grass hay our local horses have to try to survive on, if I could find bedding-free horse manure it would probably have a C/N more like 20:1. Manure from physically fit thoroughbred race horses is probably excellent. Using fresh horse manure in soil gave many vegetables a harsh flavor so it was first composted by mixing in some soil (a good idea because otherwise a great deal of ammonia would escape the heap). Market gardeners raising highly demanding crops like cauliflower and celery amended composted short manure by the inches-thick layer. Lesser nutrient-demanding crops like snap beans, lettuce, and roots followed these intensively fertilized vegetables without further compost. Long manures containing lots of straw were considered useful only for field crops or root vegetables. Wise farmers conserved the nitrogen and promptly composted long manures. After heating and turning the resulting C/N would probably be in a little below 20:1. After tilling it in, a short period of time was allowed while the soil digested this compost before sowing seeds. Lazy farmers spread raw manure load by load as it came from the barn and tilled it in once the entire field was covered. This easy method allows much nitrogen to escape as ammonia while the manure dries in the sun. Commercial vegetable growers had little use for long manure. One point of this brief history lesson is GIGO: garbage in, garbage out. The finished compost tends to have a C/N that is related to the ingredients that built the heap. Growers of vegetables will wisely take note. Anyone interested in learning more about preindustrial market gardening might ask their librarian to seek out a book called _French Gardening_ by Thomas Smith, published in London about 1905. This fascinating little book was written to encourage British market gardeners to imitate the Parisian marcier, who skillfully earned top returns growing out-of-season produce on intensive, double-dug raised beds, often under glass hot or cold frames. Our trendy American Biodynamic French Intensive gurus obtained their inspiration from England through this tradition. Curing the Heap The easiest and most sure-fire improver of compost quality is time. Making a heap with predominantly low C/N materials inevitably results in potent compost if nitrate loss is kept to a minimum. But the C/N of almost any compost heap, even one starting with a high C/N will eventually lower itself. The key word here is _eventually._ The most dramatic decomposition occurs during the first few turns when the heap is hot. Many people, including writers of garden books, mistakenly think that the composting ends when the pile cools and the material no longer resembles what made up the heap. This is not true. As long as a compost heap is kept moist and is turned occasionally, it will continue to decompose. "Curing" or "ripening" are terms used to describe what occurs once heating is over. A different ecology of microorganisms predominates while a heap is ripening. If the heap contains 5 to 10 percent soil, is kept moist, is turned occasionally so it stays aerobic, and has a complete mineral balance, considerable bacterial nitrogen fixation may occur. Most gardeners are familiar with the microbes that nodulate the roots of legumes. Called rhizobia, these bacteria are capable of fixing large quantities of nitrate nitrogen in a short amount of time. Rhizobia tend to be inactive during hot weather because the soil itself is supplying nitrates from the breakdown of organic matter. Summer legume crops, like cowpeas and snap beans, tend to be net consumers of nitrates, not makers of more nitrates than they can use. Consider this when you read in carelessly researched garden books and articles about the advantages of interplanting legumes with other crops because they supposedly generate nitrates that "help" their companions. But during spring or fall when lowered soil temperatures retard decomposition, rhizobia can manufacture from 80 to 200 pounds of nitrates per acre. Peas, clovers, alfalfa, vetches, and fava beans can all make significant contributions of nitrate nitrogen and smart farmers prefer to grow their nitrogen by green manuring legumes. Wise farmers also know that this nitrate, though produced in root nodules, is used by legumes to grow leaf and stem. So the entire legume must be tilled in if any net nitrogen gain is to be realized. This wise practice simultaneously increases organic matter. Rhizobia are not capable of being active in compost piles, but another class of microbes is. Called azobacteria, these free-living soil dwellers also make nitrate nitrogen. Their contribution is not potentially as great as rhizobia, but no special provision must be made to encourage azobacteria other than maintaining a decent level of humus for them to eat, a balanced mineral supply that includes adequate calcium, and a soil pH between 5.75 and 7.25. A high-yielding crop of wheat needs 60-80 pounds of nitrates per acre. Corn and most vegetables can use twice that amount. Azobacteria can make enough for wheat, though an average nitrate contribution under good soil conditions might be more like 30-50 pounds per year. Once a compost heap has cooled, azobacteria will proliferate and begin to manufacture significant amounts of nitrates, steadily lowering the C/N. And carbon never stops being digested, further dropping the C/N. The rapid phase of composting may be over in a few months, but ripening can be allowed to go on for many more months if necessary. Feeding unripened compost to worms is perhaps the quickest way to lower C/N and make a potent soil amendment. Once the high heat of decomposition has passed and the heap is cooling, it is commonly invaded by redworms, the same species used for vermicomposting kitchen garbage. These worms would not be able to eat the high C/N material that went into a heap, but after heating, the average C/N has probably dropped enough to be suitable for them. The municipal composting operation at Fallbrook, California makes clever use of this method to produce a smaller amount of high-grade product out of a larger quantity of low-grade ingredients. Mixtures of sewage sludge and municipal solid waste are first composted and after cooling, the half-done high C/N compost is shallowly spread out over crude worm beds and kept moist. More crude compost is added as the worms consume the waste, much like a household worm box. The worm beds gradually rise. The lower portion of these mounds is pure castings while the worm activity stays closer to the surface where food is available. When the beds have grown to about three feet tall, the surface few inches containing worms and undigested food are scraped off and used to form new vermicomposting beds. The castings below are considered finished compost. By laboratory analysis, the castings contain three or four times as much nitrogen as the crude compost being fed to the worms. The marketplace gives an excellent indicator of the difference