_Alfalfa_ is a protein-rich perennial legume mainly grown as animal
feed. On favorable soil it develops a deep root system, sometimes
exceeding ten feet. Alfalfa draws heavily on subsoil minerals so it
will be as rich or poor in nutrients as the subsoil it grew in. Its
average C/N is around 12:1 making alfalfa useful to compensate for
larger quantities of less potent material. Sacked alfalfa meal or
pellets are usually less expensive (and being "stemmy," have a
slightly higher C/N) than leafy, best-quality baled alfalfa hay.
Rain-spoiled bales of alfalfa hay are worthless as animal feed but
far from valueless to the composter.
Pelletized rabbit feed is largely alfalfa fortified with grain.
Naturally, rabbit manure has a C/N very similar to alfalfa and is
nutrient rich, especially if some provision is made to absorb the
urine.
_Apple pomace_ is wet and compact. If not well mixed with stiff,
absorbent material, large clumps of this or other fruit wastes can
become airless regions of anaerobic decomposition. Having a high
water content can be looked upon as an advantage. Dry hay and
sawdust can be hard to moisten thoroughly; these hydrate rapidly
when mixed with fruit pulp. Fermenting fruit pulp attracts yellow
jackets so it is sensible to incorporate it quickly into a pile and
cover well with vegetation or soil.
The watery pulp of fruits is not particularly rich in nutrients but
apple, grape, and pear pulps are generously endowed with soft,
decomposable seeds. Most seeds contain large quantities of
phosphorus, nitrogen, and other plant nutrients. It is generally
true that plants locate much of their entire yearly nutrient
assimilation into their seeds to provide the next generation with
the best possible start. Animals fed on seeds (such as chickens)
produce the richest manures.
Older books about composting warn about metallic pesticide residues
adhering to fruit skins. However, it has been nearly half a century
since arsenic and lead arsenate were used as pesticides and mercury
is no longer used in fungicides.
_Bagasse_ is the voluminous waste product from extracting cane
sugar. Its C/N is extremely high, similar to wheat straw or sawdust,
and it contains very little in the way of plant nutrients. However,
its coarse, strong, fibrous structure helps build lightness into a
pile and improve air flow. Most sugar mills burn bagasse as their
heat source to evaporate water out of the sugary juice squeezed from
the canes. At one time there was far more bagasse produced than the
mills needed to burn and bagasse often became an environmental
pollutant. Then, bagasse was available for nothing or next to
nothing. These days, larger, modern mills generate electricity with
bagasse and sell their surplus to the local power grid. Bagasse is
also used to make construction fiberboard for subwall and
insulation.
_Banana skins _and stalks are soft and lack strong fiber. They are
moderately rich in phosphorus, potassium, and nitrogen. Consequently
they rot quickly. Like other kitchen garbage, banana waste should be
put into the core of a compost pile to avoid attracting and breeding
flies. See also: _Garbage._
_Basic slag_ is an industrial waste from smelting iron. Ore is
refined by heating it with limestone and dolomite. The impurities
combine with calcium and magnesium, rise to the surface of the
molten metal, and are skimmed off. Basic slag contains quite a bit
of calcium plus a variety of useful plant nutrients not usually
found in limestone. Its exact composition varies greatly depending
on the type of ore used.
Slag is pulverized and sold in sacks as a substitute for
agricultural lime. The intense biological activity of a compost pile
releases more of slag's other mineral content and converts its
nutrients to organic substances that become rapidly available once
the compost is incorporated into soil. Other forms of powdered
mineralized rock can be similarly added to a compost pile to
accelerate nutrient release.
Rodale Press, publisher of _Organic Gardening_ magazine is located
in Pennsylvania where steel mills abound. Having more experience
with slag, Rodale advises the user to be alert to the fact that some
contain little in the way of useful nutrients and/or may contain
excessive amounts of sulfur. Large quantities of sulfur can acidify
soil. Read the analysis on the label. Agriculturally useful slag has
an average composition of 40 percent calcium and 5 percent
magnesium. It must also be very finely ground to be effective. See
also: _Lime_ and _Rock dust._
_Beet wastes,_ like bagasse, are a residue of extracting sugar. They
have commercial value as livestock feed and are sold as dry pulp in
feed stores located near regions where sugar beets are grown. Their
C/N is in the vicinity of 20:1 and they may contain high levels of
potassium, reaching as much as 4 percent.
_Brewery wastes._ Both spent hops (dried flowers and leaves) and
malt (sprouted barley and often other grains) are potent nutrient
sources with low C/N ratios. Spent malt is especially potent because
brewers extract all the starches and convert them to sugar, but
consider the proteins as waste because proteins in the brew make it
cloudy and opaque. Hops may be easier to get. Malt has uses as
animal feed and may be contracted for by some local feedlot or
farmer. These materials will be wet, heavy and frutily odoriferous
(though not unpleasantly so) and you will want to incorporate them
into your compost pile immediately.
_Buckwheat hulls._ Buckwheat is a grain grown in the northeastern
United States and Canada. Adapted to poor, droughty soils, the crop
is often grown as a green manure. The seeds are enclosed in a
thin-walled, brown to black fibrous hulls that are removed at a
groat mill. Buckwheat hulls are light, springy, and airy. They'll
help fluff up a compost heap. Buckwheat hulls are popular as a mulch
because they adsorb moisture easily, look attractive, and stay in
place. Their C/N is high. Oat and rice hulls are similar products.
_Canola meal._ See: _Cottonseed meal._
_Castor pomace_ is pulp left after castor oil has been squeezed from
castor bean seeds. Like other oil seed residues it is very high in
nitrogen, rich in other plant nutrients, particularly phosphorus,
Castor pomace may be available in the deep South; it makes a fine
substitute for animal manure.
_Citrus wastes_ may be available to gardeners living near industrial
processors of orange, lemon, and grapefruit. In those regions, dried
citrus pulp may also be available in feed stores. Dried orange skins
contain about 3 percent phosphorus and 27 percent potassium. Lemons
are a little higher in phosphorus but lower in potassium. Fruit
culls would have a similar nutrient ratio on a dry weight basis, but
they are largely water. Large quantities of culls could be useful to
hydrate stubbornly dry materials like straw or sawdust.
Like other byproducts of industrial farming, citrus wastes may
contain significant amounts of pesticide residues. The composting
process will break down and eliminate most toxic organic residues,
especially if the pile gets really hot through and through. (See
also: _Leaves) _The effect of such high levels of potassium on the
nutritional qualities of my food would also concern me if the
compost I was making from these wastes were used for vegetable
gardening.
_Coffee grounds_ are nutrient-rich like other seed meals. Even after
brewing they can contain up to 2 percent nitrogen, about 1/2 percent
phosphorus and varying amounts of potassium usually well below 1
percent. Its C/N runs around 12:1. Coffee roasters and packers need
to dispose of coffee chaff, similar in nutrient value to used
grounds and may occasionally have a load of overly roasted beans.
Coffee grounds seem the earthworm's food of choice. In worm bins,
used grounds are more vigorously devoured than any other substance.
If slight odor is a consideration, especially if doing in-the-home
vermicomposting, coffee grounds should be incorporated promptly into
a pile to avoid the souring that results from vinegar-producing
bacteria. Fermenting grounds may also attract harmless fruit flies.
Paper filters used to make drip coffee may be put into the heap or
worm box where they contribute to the bedding. See also: _Paper._
_Corncobs_ are no longer available as an agricultural waste product
because modern harvesting equipment shreds them and spits the
residue right back into the field. However, home gardeners who fancy
sweet corn may produce large quantities of cobs. Whole cobs will
aerate compost heaps but are slow to decompose. If you want your
pile ready within one year, it is better to dry and then grind the
cobs before composting them.
_Cottonseed meal_ is one of this country's major oil seed residues.
The seed is ginned out of the cotton fiber, ground, and then its oil
content is chemically extracted. The residue, sometimes called oil
cake or seed cake, is very high in protein and rich in NPK. Its C/N
runs around 5:1, making it an excellent way to balance a compost
pile containing a lot of carboniferous materials.
Most cottonseed meal is used as animal feed, especially for beef and
dairy cattle. Purchased in garden stores in small containers it is
very expensive; bought by the 50-to 80-pound sack from feed stores
or farm coops, cottonseed meal and other oil seed meals are quite
inexpensive. Though prices of these types of commodities vary from
year to year, oil cakes of all kinds usually cost between $200 to
$400 per ton and only slightly higher purchased sacked in
less-than-ton lots.
The price of any seed meal is strongly influenced by freight costs.
Cottonseed meal is cheapest in the south and the southwest where
cotton is widely grown. Soybean meal may be more available and
priced better in the midwest. Canadian gardeners are discovering
canola meal, a byproduct from producing canola (or rapeseed) oil.
When I took a sabbatical in Fiji, I advised local gardeners to use
coconut meal, an inexpensive "waste" from extracting coconut oil.
And I would not be at all surprised to discover gardeners in South
Dakota using sunflower meal. Sesame seed, safflower seed, peanut and
oil-seed corn meals may also be available in certain localities.
Seed meals make an ideal starting point for compounding complete
organic fertilizer mixes. The average NPK analysis of most seed
meals is around 6-4-2. Considered as a fertilizer, oil cakes are
somewhat lacking in phosphorus and sometimes in trace minerals. By
supplementing them with materials like bone meal, phosphate rock,
kelp meal, sometimes potassium-rich rock dusts and lime or gypsum, a
single, wide-spectrum slow-release trace-mineral-rich organic
fertilizer source can be blended at home having an analysis of about
5-5-5. Cottonseed meal is particularly excellent for this purpose
because it is a dry, flowing, odorless material that stores well. I
suspect that cottonseed meal from the southwest may be better
endowed with trace minerals than that from leached-out southeastern
soils or soy meal from depleted midwestern farms. See the last
section of Chapter Eight.
Some organic certification bureaucracies foolishly prohibit or
discourage the use of cottonseed meal as a fertilizer. The rationale
behind this rigid self-righteousness is that cotton, being a nonfood
crop, is sprayed with heavy applications of pesticides and/or
herbicides that are so hazardous that they not permitted on food
crops. These chemicals are usually dissolved in an emulsified
oil-based carrier and the cotton plant naturally concentrates
pesticide residues and breakdown products into the oily seed.
I believe that this concern is accurate as far as pesticide residues
being translocated into the seed. However, the chemical process used
to extract cottonseed oil is very efficient The ground seeds are
mixed with a volatile solvent similar to ether and heated under
pressure in giant retorts. I reason that when the solvent is
squeezed from the seed, it takes with it all not only the oil, but,
I believe, virtually all of the pesticide residues. Besides, any
remaining organic toxins will be further destroyed by the biological
activity of the soil and especially by the intense heat of a compost
pile.
What I _personally_ worry about is cottonseed oil. I avoid prepared
salad dressings that may contain cottonseed oil, as well as many
types of corn and potato chips, tinned oysters, and other prepared
food products. I also suggest that you peek into the back of your
favorite Oriental and fast food restaurants and see if there aren't
stacks of ten gallon cottonseed oil cans waiting to fill the
deep-fat fryer. I fear this sort of meal as dangerous to my health.
If you still fear that cottonseed meal is also a dangerous product
then you certainly won't want to be eating feedlot beef or drinking
milk or using other dairy products from cattle fed on cottonseed
meal.
_Blood meal_ runs 10-12 percent nitrogen and contains significant
amounts of phosphorus. It is the only organic fertilizer that is
naturally water soluble. Blood meal, like other slaughterhouse
wastes, may be too expensive for use as a compost activator.
Sprinkled atop soil as a side-dressing, dried blood usually provokes
a powerful and immediate growth response. Blood meal is so potent
that it is capable of burning plants; when applied you must avoid
getting it on leaves or stems. Although principally a source of
nitrogen, I reason that there are other nutritional substances like
growth hormones or complex organic "phytamins" in blood meal.
British glasshouse lettuce growers widely agree that lettuce
sidedressed with blood meal about three weeks before harvest has a
better "finish," a much longer shelf-life, and a reduced tendency to
"brown butt" compared to lettuce similarly fertilized with urea or
chemical nitrate sources.
_Feathers_ are the birds' equivalent of hair on animals and have
similar properties. See _Hair_
_Fish and shellfish waste._ These proteinaceous, high-nitrogen and
trace-mineral-rich materials are readily available at little or no
cost in pickup load lots from canneries and sea food processors.
However, in compost piles, large quantities of these materials
readily putrefy, make the pile go anaerobic, emit horrid odors, and
worse, attract vermin and flies. To avoid these problems, fresh
seafood wastes must be immediately mixed with large quantities of
dry, high C/N material. There probably are only a few homestead
composters able to utilize a ton or two of wet fish waste at one
time.
Oregonians pride themselves for being tolerant, slow-to-take-offense
neighbors. Along the Oregon coast, small-scale market gardeners will
thinly spread shrimp or crab waste atop a field and promptly till it
in. Once incorporated in the soil, the odor rapidly dissipates. In
less than one week.
_Fish meal_ is a much better alternative for use around the home. Of
course, you have to have no concern for cost and have your mind
fixed only on using the finest possible materials to produce the
nutritionally finest food when electing to substitute fish meal for
animal manures or oil cakes. Fish meal is much more potent than
cottonseed meal. Its typical nutrient analysis runs 9-6-4. However,
figured per pound of nutrients they contain, seed meals are a much
less expensive way to buy NPK. Fish meal is also mildly odoriferous.
The smell is nothing like wet seafood waste, but it can attract
cats, dogs, and vermin.
What may make fish meal worth the trouble and expense is that sea
water is the ultimate depository of all water-soluble nutrients that
were once in the soil. Animals and plants living in the sea enjoy
complete, balanced nutrition. Weston Price's classic book,
_Nutrition and Physical Degeneration,_ attributes nearly perfect
health to humans who made seafoods a significant portion of their
diets. Back in the 1930s--before processed foods were universally
available in the most remote locations-people living on isolated sea
coasts tended to live long, have magnificent health, and perfect
teeth. See also: _Kelp meal._
_Garbage. _Most forms of kitchen waste make excellent compost. But
Americans foolishly send megatons of kitchen garbage to landfills or
overburden sewage treatment plants by grinding garbage in a
disposal. The average C/N of garbage is rather low so its presence
in a compost heap facilitates the decomposition of less potent
materials. Kitchen garbage can also be recycled in other ways such
as vermicomposting (worm boxes) and burying it in the garden in
trenches or post holes. These alternative composting methods will be
discussed in some detail later.
Putting food scraps and wastes down a disposal is obviously the
least troublesome and apparently the most "sanitary" method, passing
the problem on to others. Handled with a little forethought,
composting home food waste will not breed flies or make the kitchen
untidy or ill smelling. The most important single step in keeping
the kitchen clean and free of odor is to put wastes in a small
plastic bucket or other container of one to two gallons in size, and
empty it every few days. Periodically adding a thin layer of sawdust
or peat moss supposedly helps to prevent smells. In our kitchen,
we've found that covering the compost bucket is no alternative to
emptying it. When incorporating kitchen wastes into a compost pile,
spread them thinly and cover with an inch or two of leaves, dry
grass, or hay to adsorb wetness and prevent access by flies. It may
be advisable to use a vermin-tight composting bin.
_Granite dust._ See _Rock dust._
_Grape wastes._ See _Apple pomace._
_Grass clippings._ Along with kitchen garbage, grass clippings are
the compostable material most available to the average homeowner.
Even if you (wisely) don't compost all of your clippings (see
sidebar), your foolish neighbors may bag theirs up for you to take
away. If you mulch with grass clippings, make sure the neighbors
aren't using "weed and feed" type fertilizers, or the clippings may
cause the plants that are mulched to die. Traces of the those types
of broadleaf herbicides allowed in "weed and feed" fertilizers, are
thoroughly decomposed in the composting process.
It is not necessary to return every bit of organic matter to
maintain a healthy lawn. Perhaps one-third to one-half the annual
biomass production may be taken away and used for composting without
seriously depleting the lawn's vigor--especially if one application
of a quality fertilizer is given to the lawn each year. Probably the
best time of year to remove clippings is during the spring while the
grass is growing most rapidly. Once a clover/grass mix is
established it is less necessary to use nitrogen fertilizers. In
fact, high levels of soil nitrates reduces the clover's ability to
fix atmospheric nitrogen. However, additions of other mineral
nutrients like phosphorus, potassium, and especially calcium may
still be necessary.
Lawn health is similar to garden health. Both depend on the presence
of large enough quantities of organic material in the soil. This
organic matter holds a massive reserve of nutrition built up over
the years by the growing plants themselves. When, for reasons of
momentary aesthetics, we bag up and remove clippings from our lawn,
we prevent the grass from recycling its own fertility.
It was once mistakenly believed that unraked lawn clippings built up
on the ground as unrotted thatch, promoting harmful insects and
diseases. This is a half-truth. Lawns repeatedly fertilized with
sulfur-based chemical fertilizers, especially ammonium sulfate and
superphosphate, become so acid and thus so hostile to bacterial
decomposition and soil animals that a thatch of unrotted clippings
and dead sod can build up and thus promote disease and insect
problems.
However, lawns given lime or gypsum to supply calcium that is so
vital to the healthy growth of clover, and seed meals and/or
dressings of finely decomposed compost or manure become naturally
healthy. Clippings falling on such a lawn rot rapidly because of the
high level of microorganisms in the soil, and disappear in days.
Dwarf white clover can produce all the nitrate nitrogen that grasses
need to stay green and grow lustily. Once this state of health is
developed, broadleaf weeds have a hard time competing with the lusty
grass/clover sod and gradually disappear. Fertilizing will rarely be
necessary again if little biomass is removed.
Homeowners who demand the spiffy appearance of a raked lawn but
still want a healthy lawn have several options. They may compost
their grass clippings and then return the compost to the lawn. They
may use a side-discharge mower and cut two days in succession. The
first cut will leave rows of clippings to dry on the lawn; the
second cut will disintegrate those clippings and pretty much make
them disappear. Finally, there are "mulching" mowers with blades
that chop green grass clippings into tiny pieces and drops them
below the mower where they are unnoticeable.
Grass clippings, especially spring grass, are very high in nitrogen,
similar to the best horse or cow manure. Anyone who has piled up
fresh grass clippings has noticed how rapidly they heat up, how
quickly the pile turns into a slimy, airless, foul-smelling
anaerobic mess, and how much ammonia may be given off. Green grass
should be thoroughly dispersed into a pile, with plenty of dry
material. Reserve bags of leaves from the fall or have a bale of
straw handy to mix in if needed. Clippings allowed to sun dry for a
few days before raking or bagging behave much better in the compost
heap.
_Greensand._ See _Rock dust._
_Hair _contains ten times the nitrogen of most manures. It resists
absorbing moisture and readily compresses, mats, and sheds water, so
hair needs to be mixed with other wetter materials. If I had easy
access to a barber shop, beauty salon, or poodle grooming business,
I'd definitely use hair in my compost. Feathers, feather meal and
feather dust (a bird's equivalent to hair) have similar qualities.
_Hay._ In temperate climates, pasture grasses go through an annual
cycle that greatly changes their nutrient content. Lawn grasses are
not very different. The first cuttings of spring grass are potent
sources of nitrogen, high in protein and other vital mineral
nutrients. In fact, spring grass may be as good an animal feed as
alfalfa or other legume hay. Young ryegrass, for example, may exceed
two percent nitrogen-equaling about 13 percent protein. That's why
cattle and horses on fresh spring grass frisk around and why June
butter is so dark yellow, vitamin-rich and good-flavored.
In late spring, grasses begin to form seed and their chemical
composition changes. With the emergence of the seed stalk, nitrogen
content drops markedly and the leaves become more fibrous,
ligninous, and consequently, more reluctant to decompose. At
pollination ryegrass has dropped to about l percent nitrogen and by
the time mature seed has developed, to about 0.75 percent.
These realities have profound implications for hay-making, for using
grasses as green manures, and for evaluating the C/N of hay you may
be planning to use in a compost heap. In earlier times, making grass
hay that would be nutritious enough to maintain the health of cattle
required cutting the grass before, or just at, the first appearance
of seed stalks. Not only did early harvesting greatly reduce the
bulk yield, it usually meant that without concern for cost or hours
of labor the grass had to be painstakingly dried at a time of year
when there were more frequent rains and lower temperatures. In
nineteenth-century England, drying grass was draped by hand over low
hurdles, dotting each pasture with hundreds of small racks that shed
water like thatched roofs and allowed air flow from below. It is
obvious to me where the sport of running hurdles came from; I
envision energetic young countryfolk, pepped up on that rich spring
milk and the first garden greens of the year, exuberantly racing
each other across the just-mowed fields during haying season.
In more recent years, fresh wet spring grass was packed green into
pits and made into silage where a controlled anaerobic fermentation
retained its nutritional content much like sauerkraut keeps cabbage.
Silage makes drying unnecessary. These days, farm labor is expensive
and tractors are relatively inexpensive. It seems that grass hay
must be cut later when the weather is more stable, economically
dried on the ground, prevented from molding by frequent raking, and
then baled mechanically.
In regions enjoying relatively rainless springs or where agriculture
depends on irrigation, this system may result in quality hay. But
most modern farmers must supplement the low-quality hay with oil
cakes or other concentrates. Where I live, springs are cool and damp
and the weather may not stabilize until mid-June. By this date grass
seed is already formed and beginning to dry down. This means our
local grass hay is very low in protein, has a high C/N, and is very
woody--little better than wheat straw. Pity the poor horses and
cattle that must try to extract enough nutrition from this stuff.
Western Oregon weather conditions also mean that farmers often end
up with rain-spoiled hay they are happy to sell cheaply. Many years
I've made huge compost piles largely from this kind of hay. One
serious liability from cutting grass hay late is that it will
contain viable seeds. If the composting process does not thoroughly
heat all of these seeds, the compost will sprout grass all over the
garden. One last difficulty with poor quality grass hay: the tough,
woody stems are reluctant to absorb moisture.
The best way to simultaneously overcome all of these liabilities is
first to permit the bales to thoroughly spoil and become moldy
through and through before composting them. When I have a ton or two
of spoiled hay bales around, I spread them out on the ground in a
single layer and leave them in the rain for an entire winter. Doing
this sprouts most of the grass seed within the bales, thoroughly
moistens the hay, and initiates decomposition. Next summer I pick up
this material, remove the baling twine, and mix it into compost
piles with plenty of more nitrogenous stuff.
One last word about grass and how it works when green manuring. If a
thick stand of grasses is tilled in during spring before seed
formation begins, its high nitrogen content encourages rapid
decomposition. Material containing 2 percent nitrogen and lacking a
lot of tough fiber can be totally rotted and out of the way in two
weeks, leaving the soil ready to plant. This variation on green
manuring works like a charm.
However, if unsettled weather conditions prevent tillage until seed
formation has begun, the grasses will contain much less nitrogen and
will have developed a higher content of resistant lignins. If the
soil does not become dry and large reserves of nitrogen are already
waiting in the soil to balance the high C/N of mature grass, it may
take only a month to decompose But there will be so much
decomposition going on for the first few weeks that even seed
germination is inhibited. Having to wait an unexpected month or six
weeks after wet weather prevented forming an early seed bed may
delay sowing for so long that the season is missed for the entire
year. Obstacles like this must be kept in mind when considering
using green manuring as a soil-building technique. Cutting the grass
close to the soil line and composting the vegetation off the field
eliminates this problem.
_Hoof and horn meal._ Did you know that animals construct their
hooves and horns from compressed hair? The meal is similar in
nutrient composition to blood meal, leather dust, feather meal, or
meat meal (tankage). It is a powerful source of nitrogen with
significant amounts of phosphorus. Like other slaughterhouse
byproducts its high cost may make it impractical to use to adjust
the C/N of compost piles. Seed meals or chicken manure (chickens are
mainly fed seeds) have somewhat lower nitrogen contents than animal
byproducts but their price per pound of actual nutrition is more
reasonable. If hoof and horn meal is not dispersed through a pile it
may draw flies and putrefy. I would prefer to use expensive
slaughterhouse concentrates to blend into organic fertilizer mixes.
_Juicer pulp:_ See _Apple pomace._
_Kelp meals_ from several countries are available in feed and grain
stores and better garden centers, usually in 25 kg (55-pound) sacks
ranging in cost from $20 to $50. Considering this spendy price, I
consider using kelp meal more justifiable in complete organic
fertilizer mixes as a source of trace minerals than as a composting
supplement.
There is a great deal of garden lore about kelp meal's
growth-stimulating and stress-fortifying properties. Some
garden-store brands tout these qualities and charge a very high
price. The best prices are found at feed dealers where kelp meal is
considered a bulk commodity useful as an animal food supplement.
I've purchased kelp meal from Norway, Korea, and Canada. There are
probably other types from other places. I don't think there is a
significant difference in the mineral content of one source compared
to another. I do not deny that there may be differences in how well
the packers processing method preserved kelp's multitude of
beneficial complex organic chemicals that improve the growth and
overall health of plants by functioning as growth stimulants,
phytamins, and who knows what else.
Still, I prefer to buy by price, not by mystique, because, after
gardening for over twenty years, garden writing for fifteen and
being in the mail order garden seed business for seven I have been
on the receiving end of countless amazing claims by touters of
agricultural snake oils; after testing out dozens of such
concoctions I tend to disbelieve mystic contentions of unique
superiority. See also: _Seaweed_.
_Leather dust_ is a waste product of tanneries, similar to hoof and
horn meal or tankage. It may or may not be contaminated with high
levels of chromium, a substance used to tan suede. If only
vegetable-tanned leather is produced at the tannery in question,
leather dust should be a fine soil amendment. Some organic
certification bureaucrats prohibit its use, perhaps rightly so in
this case.
_Leaves._ Soil nutrients are dissolved by rain and leached from
surface layers, transported to the subsoil, thence the ground water,
and ultimately into the salty sea. Trees have deep root systems,
reaching far into the subsoil to bring plant nutrients back up,
making them nature's nutrient recycler. Because they greatly
increase soil fertility, J. Russell Smith called trees "great
engines of production." Anyone who has not read his visionary book,
_Tree Crops, _should. Though written in 1929, this classic book is
currently in print.
Once each year, leaves are available in large quantity, but aren't
the easiest material to compost. Rich in minerals but low in
nitrogen, they are generally slow to decompose and tend to pack into
an airless mass. However, if mixed with manure or other
high-nitrogen amendment and enough firm material to prevent
compaction, leaves rot as well as any other substance. Running dry
leaves through a shredder or grinding them with a lawnmower greatly
accelerates their decomposition. Of all the materials I've ever put
through a garden grinder, dry leaves are the easiest and run the
fastest.
Once chopped, leaves occupy much less volume. My neighbor, John, a
very serious gardener like me, keeps several large garbage cans
filled with pulverized dry leaves for use as mulch when needed. Were
I a northern gardener I'd store shredded dry leaves in plastic bags
over the winter to mix into compost piles when spring grass
clippings and other more potent materials were available. Some
people fear using urban leaves because they may contain automotive
pollutants such as oil and rubber components. Such worries are
probably groundless. Dave Campbell who ran the City of Portland
(Oregon) Bureau of Maintenance leaf composting program said he has
run tests for heavy metals and pesticide residues on every windrow
of compost he has made.
"Almost all our tests so far have shown less than the background
level for heavy metals, and no traces of pesticides [including]
chlorinated and organophosphated pesticides.... It is very rare for
there to be any problem."
Campbell tells an interesting story that points out how thoroughly
composting eliminates pesticide residues. He said,
"Once I was curious about some leaves we were getting from a city
park where I knew the trees had been sprayed with a pesticide just
about a month before the leaves fell and we collected them. In this
case, I had the uncomposted leaves tested and then the compost
tested. In the fresh leaves a trace of . . . residue was detected,
but by the time the composting process was finished, no detectable
level was found."
_Lime._ There is no disputing that calcium is a vital soil nutrient
as essential to the formation of plant and animal proteins as
nitrogen. Soils deficient in calcium can be inexpensively improved
by adding agricultural lime which is relatively pure calcium
carbonate (CaC03). The use of agricultural lime or dolomitic lime in
compost piles is somewhat controversial. Even the most authoritative
of authorities disagree. There is no disputing that the calcium
content of plant material and animal manure resulting from that
plant material is very dependent on the amount of calcium available
in the soil. Chapter Eight contains quite a thorough discussion of
this very phenomena. If a compost pile is made from a variety of
materials grown on soils that contained adequate calcium, then
adding additional lime should be unnecessary. However, if the
materials being composted are themselves deficient in calcium then
the organisms of decomposition may not develop fully.
While preparing this book, I queried the venerable Dr. Herbert H.
Koepf about lime in the compost heap. Koepf's biodynamic books
served as my own introduction to gardening in the early 1970s. He is
still active though in his late seventies. Koepf believes that lime
is not necessary when composting mixtures that contain significant
amounts of manure because the decomposition of proteinaceous
materials develops a more or less neutral pH. However, when
composting mixtures of vegetation without manure, the conditions
tend to become very acid and bacterial fermentation is inhibited. To
correct low pH, Koepf recommends agricultural lime at 25 pounds per
ton of vegetation, the weight figured on a dry matter basis. To
guestimate dry weight, remember that green vegetation is 70-80
percent water, to prevent organic material like hay from spoiling it
is first dried down to below 15 percent moisture.
There is another reason to make sure that a compost pile contains an
abundance of calcium. Azobacteria, that can fix nitrate nitrogen in
mellowing compost piles, depend for their activity on the
availability of calcium. Adding agricultural lime in such a
situation may be very useful, greatly speed the decomposition
process, and improve the quality of the compost. Albert Howard used
small amounts of lime in his compost piles specifically to aid
nitrogen fixation. He also incorporated significant quantities of
fresh bovine manure at the same time.
However, adding lime to heating manure piles results in the loss of
large quantities of ammonia gas. Perhaps this is the reason some
people are opposed to using lime in any composting process. Keep in
mind that a manure pile is not a compost pile. Although both will
heat up and decay, the starting C/N of a barnyard manure pile runs
around 10:1 while a compost heap of yard waste and kitchen garbage
runs 25:1 to 30:1. Any time highly nitrogenous material, such as
fresh manures or spring grass clippings, are permitted to decompose
without adjustment of the carbon-to-nitrogen ratio with less potent
stuff, ammonia tends to be released, lime or not.
Only agricultural lime or slightly better, dolomitic lime, are
useful in compost piles. Quicklime or slaked lime are made from
heated limestone and undergo a violent chemical reaction when mixed
with water. They may be fine for making cement, but not for most
agricultural purposes.
_Linseed meal._ See _Cottonseed meal_.
_Manure._ Fresh manure can be the single most useful addition to the
compost pile. What makes it special is the presence of large
quantities of active digestive enzymes. These enzymes seem to
contribute to more rapid heating and result in a finer-textured,
more completely decomposed compost that provokes a greater growth
response in plants. Manure from cattle and other multi-stomached
ruminants also contains cellulose-decomposing bacteria. Soil animals
supply similar digestive enzymes as they work over the litter on the
forest floor but before insects and other tiny animals can eat much
of a compost heap, well-made piles will heat up, driving out or
killing everything except microorganisms and fungi.
All of the above might be of interest to the country dweller or
serious backyard food grower but probably sounds highly impractical
to most of this book's readers. Don't despair if fresh manure is not
available or if using it is unappealing. Compost made with fresh,
unheated manure works only a little faster and produces just a
slightly better product than compost activated with seed meals,
slaughterhouse concentrates, ground alfalfa, grass clippings,
kitchen garbage, or even dried, sacked manures. Compost made without
any manure still "makes!"
When evaluating manure keep in mind the many pitfalls. Fresh manure
is very valuable, but if you obtain some that has been has been
heaped up and permitted to heat up, much of its nitrogen may already
have dissipated as ammonia while the valuable digestive enzymes will
have been destroyed by the high temperatures at the heap's core. A
similar degradation happens to digestive enzymes when manure is
dried and sacked. Usually, dried manure comes from feedlots where it
has also first been stacked wet and gone through a violent heating
process. So if I were going to use sacked dried manure to lower the
C/N of a compost pile, I'd evaluate it strictly on its cost per
pound of actual nitrogen. In some cases, seed meals might be cheaper
and better able to drop the heap's carbon-to-nitrogen ratio even
more than manure.
There are many kinds of manure and various samples of the same type
of manure may not be equal. This demonstrates the principle of what
goes in comes out. Plants concentrate proteins and mineral nutrients
in their seed so animals fed on seed (like chickens) excrete manure
nearly as high in minerals and with a C/N like seed meals (around
8:1). Alfalfa hay is a legume with a C/N around 12:1. Rabbits fed
almost exclusively on alfalfa pellets make a rich manure with a
similar C/N. Spring grass and high quality hay and other leafy
greens have a C/N nearly as good as alfalfa. Livestock fed the best
hay supplemented with grain and silage make fairly rich manure. Pity
the unfortunate livestock trying to survive as "strawburners" eating
overly mature grass hay from depleted fields. Their manure will be
as poor as the food and soil they are trying to live on.
When evaluating manure, also consider the nature and quantity of
bedding mixed into it. Our local boarding stables keep their lazy
horses on fir sawdust. The idle "riding" horses are usually fed very
strawy local grass hay with just enough supplemental alfalfa and
grain to maintain a minimal healthy condition. The "horse manure"
I've hauled from these stables seems more sawdust than manure. It
must have a C/N of 50 or 60:1 because by itself it will barely heat
up.
Manure mixed with straw is usually richer stuff. Often this type
comes from dairies. Modern breeds of milk cows must be fed seed
meals and other concentrates to temporarily sustain them against
depletion from unnaturally high milk production.
After rabbit and chicken, horse manure from well-fed animals like
race horses or true, working animals may come next. Certainly it is
right up there with the best cow manure. Before the era of chemical
fertilizer, market gardeners on the outskirts of large cities took
wagon loads of produce to market and returned with an equivalent
weight of "street sweepings." What they most prized was called
"short manure," or horse manure without any bedding. Manure and
bedding mixtures were referred to as "long manure" and weren't
considered nearly as valuable.
Finally, remember that over half the excretion of animals is urine.
And far too little value is placed on urine. As early as 1900 it was
well known that if you fed one ton (dry weight) of hay and measured
the resulting manure after thorough drying, only 800 pounds was
left. What happened to the other 1,200 pounds of dry material? Some,
of course, went to grow the animal. Some was enzymatically "burned"
as energy fuel and its wastes given off as CO2 and H2O. Most of it
was excreted in liquid form. After all, what is digestion but an
enzymatic conversion of dry material into a water solution so it can
be circulated through the bloodstream to be used and discarded as
needed. Urine also contains numerous complex organic substances and
cellular breakdown products that improve the health of the soil
ecology.
However, urine is not easy to capture. It tends to leach into the
ground or run off when it should be absorbed into bedding. Chicken
manure and the excrements of other fowl are particularly valuable in
this respect because the liquids and solids of their waste are
uniformly mixed so nothing is lost. When Howard worked out his
system of making superior compost at Indore, he took full measure of
the value of urine and paid great care to its capture and use.
_Paper_ is almost pure cellulose and has a very high C/N like straw
or sawdust. It can be considered a valuable source of bulk for
composting if you're using compost as mulch. Looked upon another
way, composting can be a practical way to recycle paper at home.
The key to composting paper is to shred or grind it. Layers of paper
will compress into airless mats. Motor-driven hammermill shredders
will make short work of dry paper. Once torn into tiny pieces and
mixed with other materials, paper is no more subject to compaction
than grass clippings. Even without power shredding equipment,
newsprint can be shredded by hand, easily ripped into narrow strips
by tearing whole sections along the grain of the paper, not fighting
against it.