WHAT TO COMPOST
Anything and everything organic is the answer.
Of the many definitions of compost, I think the most suitable one
for this section is this one:
“Compost is the result of the decomposition of organic matter by bacteria,
fungi and other organisms in the soil.”
It’s a sort of feed them and they will come affair. Offer a
delicious assortment of organic meals in the presence of water and oxygen, and
millions of hungry micro-organisms will turn up for the feast. The best part is that you don’t have to
worry about an invitation; word gets around and there they are, busy breaking
down organic compounds into smaller and smaller pieces, until all that is left
is the wonderful dark brown, crumbly material known as compost.
Every scrap of organic material that goes into the landfill route
is robbing the soil, and by extension, is reducing our quality of life. By dumping organic matter, we are literally
throwing away Nature’s most valuable resource.
All the nutrients pulled from the soil by growing plants are being
discarded, and the price of that is compaction, erosion, less fertility, poorer
crops or excessive use of fertilizer, less healthy plants and greater use of
pesticides, pollution and general environmental degradation.
Once in the landfill this mineral rich organic material is gone
for good. Let me say that again. “Gone for good.” And I’ll say it again later.
To repeat the quote from Sir Albert Howard: “Although our towns are fed from the countryside, little or no
return of urban wastes to the land takes place. The towns are, therefore, parasitic on the country. This will have to stop.”
In a way I am trying
to carry on where Sir Albert left off – trying to get organic matter back into
Yard waste, food waste, waste paper, - it’s only waste if it’s thrown away. Composted and returned to the soil, this “waste” is food for the
soil. And ALL organic matter (that is
anything that was once alive) can be composted. Nothing should be wasted, nothing should be thrown away because
as the Cornell Waste Management Institute so wittily puts it “A rind is a
terrible thing to waste”.
So too is a rotten tomato, wilted lettuce, table scraps, paper,
wood, spoilt silage, sludge, coffee grounds, leaves, grass clippings, road
kill, manure from all sources, weeds, apple and grape pomace, corn stalks,
sawdust, anything and everything biodegradable. It all can – and must – be returned to the soil.
The Cornell Waste Management Institute also offers huge amounts
of information which you can accesss by calling their ROTLINE
(607-272-2292). Someone there has a
sense of humor, but it is not really a laughing matter.
Organic matter headed to landfills is a huge problem. Not only
does it take up space, it also rots and produces methane. Very few landfill sites make use of this gas
for energy purposes. In most cases it
is released into the atmosphere where, guess what?, it contributes to
greenhouse gases and global warming. (see http://compostingcouncil.org/admin/wp-content/uploads/2010/09/Compost-Use-Mitigates-Climate-Change.pdf)
compost-makers and other recyclers can slow the inexorable march from land to
landfill by creating ever-increasing numbers of permanent detours, resulting in
self-sustaining cyclical systems for organic matter, otherwise known as compost
Petrochemicals and TNT may need an expert to render them safe and
useable, but into your home compost heap you can put all that stuff that is
usually called waste: kitchen “waste”, yard “waste”, “waste” paper, even human
Yes you can compost the stuff that humans produce on a daily
basis, but don’t like to talk about in polite company. You absolutely must read “The Humanure
Handbook” by Joe Jenkins, which contains this passage: “The world is divided
into two categories of people: those who shit in their drinking water
supplies and those who don’t.”
Having got your attention, he goes on to present a hugely
compelling argument as to why the world should be striving extremely hard to
keep human excrement out of the “waste” stream. Because, as he points out, it’s only waste if you throw it away. Six billion human beings on this planet produce
a shitload of shit, which is either being shipped to landfills or left to
contaminate water supplies. What a tragedy, what a disaster, because shit and
all organic material is an enormous, incredibly valuable resource, which, once
in the landfill is, I repeat, lost to us forever.
Organic matter – that is plants and the animals which eat them -
arise from the soil, mining in a small way minerals contained in that soil.
There is a finite amount of minerals in the soil, so that it is imperative that
these minerals be returned to the soil. But instead we in the West like to
throw it all away. I’ll say it again,
once in the landfill it is lost to us forever.
Have I made my point yet?
Most North Americans and Europeans are probably not ready to
replace their flush toilets with buckets of sawdust, but waterless toilets are
worth considering for emergencies, your cabin in the woods, or a new, “green”
habitation. Certainly aid to developing
countries should not include water-born sanitation systems, which strain the
natural resources and remove valuable nutrients from the soil-food-soil cycle.
In countries where flush toilets are a way of life, we must
strive to the best of our abilities to keep sludge (the end-product of
waste-water treatment facilities) out of the landfills. This is not because it taxes the landfill
system, but because the nutrient value of sludge is far too high to just throw
it away. Sludge can
safely be composted to everyone’s benefit (see Large-scale composting).
Having got the “dirty” stuff out of the way and mentioned
nitrogen, this is probably the place to explain the C:N ratio, which you will
see in every book about compost.
Bacteria, which are the primary decomposers, require a balance of
available carbon and nitrogen in the presence of water and oxygen to be able to
do their invaluable work. They use
carbon for energy and nitrogen to reproduce, and they need 25 times as much
carbon as nitrogen. Not surprisingly,
therefore, the ideal ration of carbon to nitrogen in a compost pile is 25:1,
more or less.
If the carbon content is very high, decomposition will slow down;
if the nitrogen content is too high, decomposition will be very rapid, using up
all available air and causing the pile to become anaerobic. To put it bluntly, the pile will turn slimy
and begin to stink. If you are within
the 20:1 to 30:1 range you are fine.
There are formulas for calculating
how much green and how much brown material is needed. In
practice, a bucket of carbon-rich material for each bucket of nitrogen-rich
material works quite well as a rule of thumb.
Carbon-rich material, also known as brown material is anything
that has died off or dried out through natural processes.
Nitrogen-rich materials, also known as greens, are anything of
animal origin, or recently harvested plant materials, even if they have now
withered. The exception is coffee grounds which may look brown, but they act as green.
Not many of us have heaps of peanut shells or seaweed just crying
out to be composted. Obviously, we
compost what we have on hand. For most of us, that is garden debris and kitchen
scraps. Note that I don’t call them
waste, because, remember, they are only waste if you throw them away.
Most books will tell you that there are things you mustn’t
compost, such as meat scraps, oils, pet litter, egg shells, orange rinds. Everything of organic origin – with the
unfortunate exception of plastic- CAN be composted. Sometimes you may choose not to.
Meat scraps are a great source of nitrogen, but may attract dogs
and other animals. If you make sure
that you bury them deep in your pile, they should not be a problem. Alternatively, you can process then in your
blender into a compost soup, so that there is just not enough for an animal to
get its teeth into.
Earthworms apparently do not like oils and fats, but they can
safely be added to the compost pile in small quantities. This is much better than tossing them down
the drain, as fats are the biggest problem that municipal waste management
systems contend with, as they tend to clog the drains.
The strongest argument against pet excrement is that it may
contain pathogens. If you have healthy pets, you probably don’t have a problem
at all and this is only a potential problem if the compost is to be used in the
vegetable garden. The problem can be overcome in four different ways:
Ensure that your pile reaches 131º Fahrenheit for at least three
days (see how to compost)
Leave the pile to mature for at least a year
Keep a separate pile for ornamental plants only
Bury the excrement in a quiet corner of the garden
Clay-type cat litter will sit around for ages (who in their right
mind will add clay to soil that you are trying to lighten?) but there are
“green” litters made from corn or pine or newspaper that will compost
beautifully. Newspaper, however, does not work very well as a litter.
Eggshells can be put into the compost heap with no problem at
all. They do break down slowly, but
roughly crushed they add some structure to the pile. For the most part, I do not put my eggshells in the compost, but
that is only because I have a better use for them. I crush them and use them as a mulch under plants that slugs love
– zucchini, cucumbers, hosta. As long
as the leaves don’t touch the soil, the slugs will not be able to get to them
as the eggshells rip them to pieces.
Gruesome but effective.
I also don’t put citrus rinds into the compost, again, not
because I shouldn’t, but because I have a better use for them, too: I put them
down my garbage disposal to clean it out. I don’t use it much, but there are
times when it really is the best solution.
If I knew that my municipality composted sewage sludge, I would feel a
lot less guilty about using a garbage disposal unit.
Little aside here. When
we redid our kitchen and installed the garbage disposal, I asked the contractor
whether it would be possible to divert the water to a barrel, so that I could
then use it on the garden. Absolutely
not, was the answer in 1994. But it can
be done. What a wonderful solution to those chicken bones and other supposedly
uncompostable kitchen products. And if you use a permeable bag inside your
barrel, you can lift that out and put the solids in the compost, while the
enriched liquid can be used for watering purposes.
Surfing that wonderful resource, the worldwide web, I came across
a list of “163 Things You Can Compost” by Marion Owen, co-author of Chicken
Soup for the Gardener's Soul. Some
of these items are a real stretch, but their presence on the list that follows
underlines the fact that you can compost anything organic, and
that it is as easy to toss them into the compost bucket as it is to toss them
into the garbage.Selected items include:
Blood meal and bone meal – both of these will boost
your compost activity, but I feel that going out and buying them at the Garden
Center is somewhat like buying fabric to cut up to make patchwork quilts. The
spirit of both patchwork and compost is all about using what you have on hand,
or which you can get easily, free or in trade.
Coffee grounds – these are among the very best, fastest acting
materials that you can add to your heap.
Perhaps you are a coffaholic and produce vast quantities of grounds each
day, perhaps not. This is an area where
you can co-operate with others to find the right stuff for your pile. Perhaps
there is an overworked coffee machine at your place of business. Nab the grounds before someone else does! Perhaps you stop at your favourite coffee
shop each morning. Ask them what they
do with their grounds, and offer to reduce their garbage.
Food scraps - dig them
into the pile, or cover with a good layer of brown material. Odor is not usually a problem, but flies can
garden debris – the mainstay of the home compost pile. Reduce the size as much as possible,
utilizing the lawn mower, weed wacker or machete, especially for woodier
clippings. When pruning, it takes very
little extra time to cut the twigs and branches into 3-4” pieces. You will obviously have bigger pieces which
require a lot of work to reduce them to compostable size. If your city collects and composts yard
debris, use their service. If not find
a secluded part of the garden, behind or under bushes where you can deposit all
the larger pieces that do appear at regular intervals. Just leave them there for a couple of
years. They, too, will break down over
time. Or dig a pit and dump them all in
grass clippings – the best reason for having a lawn, perhaps the
only reason for having a lawn. For the
most part, however, the clippings should be left on the lawn. As long as the clipping are not longer than
an inch and a half, these will be the only nourishment the lawn needs. From time to time, however, you may want to
rake up the lawn clippings to add to the compost. Just make sure that you don’t layer the grass so thickly that it
excludes air. In an airless (anaerobic)
situation, grass clippings quickly become slimy and smelly.
hay – best used in a hot pile, as it will contain many
seeds. Actually, I don’t find seedlings
in the compost to be a huge problem.
Small seedlings are very easy to pull up. Just leave them on the surface of the soil as a mini green
mulch. I don’t cultivate the soil, I
just brush the baby plants aside.
Leaves – THE BEST. Chop
them if you can, using a leaf-chomping device, a lawn-mower, a leaf vacuum or
your weed wacker. The leaf-chomper (the
technical term, you understand, often it is called Flowtron
LE-900 Electric Leaf Shredder) is a funnel with a string cutter at the
bottom. Very light, very effective, around
Rake all your leaves on to your lawn prior to your last mow of
the season. The combination of chopped
up leaves and grass clippings makes perfect compost. Pile them all up, and by spring you will have a very useable
product. If you don’t have enough trees, drive around the neighbourhood and
pick up bagged leaves to stockpile an use during the summer.
manures – from herbivores, it is totally without problems and the
best stuff in the world for your compost.
I have already talked about humanure and pet excrement. (see thehumanurehandbook.com) If you can get your hands on horse, cow,
rabbit or chicken manure, grab it! Especially if it is already mixed with some
type of bedding material. Manure is generally too strong to put directly on to
growing areas, but added to the compost pile, it is the most wonderful
stuff. Mix it in well so that there is
not too great a concentration in any one part of the pile.
Pine needles – slow to break down. They are perhaps better utilised as a mulch for acid loving
plants such as blueberries, azaleas and rhododendrons.
Sawdust – used in great quantities by commercial compost
operations, where it is well mixed with the other ingredients prior to adding
to the pile. In the home pile, you need
to sprinkle it on in small quantities, or else you will have a solid layer
which blocks the passage of water, and reduces air flow.
shredded newspaper - great to sprinkle on top of kitchen scraps or other very wet material, but avoid matting.
straw – very useful in the garden. Can be used as a mulch for (surprise!) strawberries and other
edible plants. Also frequently used to
cover grass seeds when re-seeding or patching the lawn. Great to use as a material to cover kitchen
scraps. It will break down eventually,
but unless you put your machete to good use before adding straw to the pile,
you will have a lot of stringy bits in your compost.
urine – a readily available, mostly sterile, highly “green”
innoculant for the compost heap. Unless
you know that you have a urinary tract infection (and believe me you know!)
your urine is a free, pathogen-free, everything free resource, easily collected
and just waiting to be used. Of course,
it is easy for the men in the household to pee in a bucket. But, if one takes a cue from the Japanese,
even the women can contribute. Japanese
toilets – holes in the ground over which one stands – were obviously developed
with kimono-wearing women in mind.
Imagine how difficult it would be for a woman wearing a traditional
kimono to use a western-style toilet. But standing, straddling the hole, works
very well. I wear a sort of kaftan to
sleep in, a loose fitting garment, to the ground. I can stand over a bucket on the deck in the early morning, and I
guarantee that no neighbor who happens to see me has any idea that I am peeing
into my compost bucket.
Weeds – the absolutely most perfect compost material that there
is. My late father-in-law claimed that the very best compost is made
from weeds with some dirt clinging to the roots. We didn’t agree on many things, but in this case he was
absolutely right. Weeds have the
perfect C:N ration, and the bit of soil attached provides an injection of
microbes just waiting to go to work.
Only the woodier weeds need to be chopped; most of the soft ones break
down very quickly as they are.
One very persistent weed is jewelweed, or impatiens capensis. This can really take hold in a garden, but
looking on the bright side, it has three really useful attributes. First it is an effective natural herbal antidote for poison ivy, poison oak, stinging nettle, and other irritants.
Second it makes fabulous compost, breaking down almost as you
look at it. If you catch it before it
goes to seed, you will enhance your heap and reduce the number of plants
popping up next year. However it is
almost worth leaving a patch in a secluded part of the garden just to feed the
compost heap. Japanese beetles love it
and thus its third use is as a decoy plant, meaning that the beetles will
congregate on the jewelweed where they can be picked off by hand and dropped
into a jar of soapy water, in which they rapidly drown
Purple loosestrife is another very effective decoy. I don’t feel bad about keeping this invasive
alien in my garden because the beetles eat all the flowers and it never sets
Two other plants that are well worth cultivating for the compost
heap are comfrey and borage. Borage is
an annual. I believe that you can eat
the leaves as cooked greens, but they are hairy and to my mind totally
unappealing. The beautiful blue flower
is the reason I planted borage in the first place. Not only is it very pretty, but it is an essential ingredient in
that quintessentially British cocktail, Pimms, as drunk at the Oxford and Cambridge
Boat Race and the Henley Royal Regatta and similar events that were at the
heart of the Empire. They are also very
attractive in salads and as a garnish for sandwiches or cheese and crackers.
However, as borage is a vigorous grower and prolific seeder, you
are going to have far more flowers than you are ever going to use. Excess plants add greatly to your compost
Comfrey is a perennial, which just keeps on growing. It is hard to get rid of, as any small piece
of root left in the soil will produce another plant. But it doesn’t set seed easily, so is not invasive, and it is so
beneficial that you really won’t want to get rid of it. I was introduced to comfrey back in South
Africa by a somewhat loony friend who was into organic gardening when Robert
Rodale was still in short pants. The
plant’s common name (among others) is boneset, and there is strong evidence
that it is effective in promoting rapid healing of broken bones. Helen, the loony friend, used it to treat
her cook’s leg, which had a wound that simply would not heal. She applied a compress of crushed leaves,
and ta-dah, the leg was fine in two shakes of a duck’s tail.
We were sure that she had exaggerated, but the University of
Maryland Medical School notes Comfrey (Symphytum officinale ) is used
to treat wounds and reduce the inflammation associated with sprains and broken
bones. The roots and leaves contain allantoin, a substance that helps new skin
cells grow, along with other substances that reduce inflammation and keep skin
healthy. Whatever its merits for humans, comfrey tea is thought to be a wonderful tonic for
ailing plants: “Place a bunch of chopped comfrey leaves at the bottom of a
bucket. Weigh down with a brick, fill bucket with water, and cover for three
weeks before diluting, one part 'tea' to 10 parts water.”
This brew is said to produce a fertiliser with more potash and
nitrogen than commercial feeds. Again,
this may be an exaggeration, but it will do none of the harm that commercial
fertilizers may. The leaves can be harvested three or four times a season and put
in the compost heap a few at a time.
(Like grass clippings, they will go slimy of there are too many of
them.) They can also be allowed to wilt
and then be applied as a mulch for tomato plants.
In general, you should try to get to weeds before they set seed,
as this reduces the (slight) nuisance of having seedlings come up wherever you
have used your compost. More
importantly, plants that have not yet set seed tend to be less woody, and thus
they break down faster.
Weeds are so important that there are times (especially in the
spring) when you don’t have enough in your garden, and may find yourself
offering to weed other people’s gardens!
This is a great way to make friends while making great compost.
Remember you can compost ANYTHING organic,
even though sometimes
you may choose not to put some materials
in your general pile.