TO PERFECT COMPOST
There are two images associated with the word compost. One is of a
rotting, fly-infested cesspool of kitchen scraps that makes you gag
if you get close. The other is rich, crumbly, pleasantly earthy
smelling black gold, the stuff of gardeners dreams.
Here are a few tips on how to avoid the former and have more of the latter.
1) Get to Know Your Greens and Browns
There are two main ingredients in any successful compost pile: carbon-rich
ingredients and nitrogen-rich ingredients. The carbon camp is often referred
to as browns,Ł because it include things like dried leaves, dried grass
clippings, cardboard, and straw. Nitrogen-rich ťgreens, on the other
hand, include fresh leaves, fresh grass clippings, and vegetable scraps; the
name is a bit of a misnomer, however, as manure, a very nitrogen-rich substance,
is also included in the green camp. You're going to need at least one source
of each for your pile.
Always start a new compost pile with a fluffy layer of browns on the bottom
(at least 6 to 8 inches deep) to absorb moisture from the pile and keep things
well-aerated, thus avoiding cesspool conditions.
2) Striking the Right Carbon-Nitrogen Balance
The magic that is composting rests on the interaction between carbon compounds
(browns) and nitrogen compounds (greens).
Any pile of organic matter (translation: this means formerly living things,
including all compost ingredients) will eventually decompose and feed the
soil, but when the ratio of carbon to nitrogen in a compost pile approaches
30 to 1, the decomposition process rapidly accelerates as thermophilicŁ
bacteria move in and the pile heats up to over 160 degrees Fahrenheit.
Check out this handy list of the carbon-nitrogen ratio for various compost
ingredients to get a general sense of how much of each to incorporate into
List of the Carbon Nitrogen Ratio
3) Get the Feel of Your Pile
There is no need to get out your calculator to know whether you're striking
the right balance carbon-nitrogen balance. When the ratio is lower than ideal
(too much nitrogen), the pile will be slimy and stinky; simply add carbon.
When the ratio is higher than ideal (too much carbon), the pile will be dry
and very slow to decompose; simply add nitrogen. In general, carbon-rich
materials should form the bulk of the pile. A good rule of thumb is that each
time you add a batch of nitrogen-rich ingredients, add roughly 4 times that
amount in carbon-rich ingredients (in volume, not weight).
Always add nitrogen sources (manure, kitchen scraps) in thin layers, not little
piles, so that all the material is in contact with carbon-rich browns.
4) Keep the Pile Covered in Carbon
In general, it's best to err on the side of too much carbon in a compost pile.
The worst that can happen is it takes longer to decompose. Extra leaves, straw,
and grass clippings, especially when used on the outside of the pile, reduce
odor and improve aesthetics. You can think of this almost as a covering, with
the composting activity occurring below; pull it back each time you had a new
layer of compost materials. Aim for at least 3 to 4 inches thick.
This outer layer of carbon won't readily decompose, so just strip it away once
the interior part of the pile has turned into dark, crumbly compost and use it
as an ingredient in your next pile.
5) Not Too Wet, Not Too Dry
The perfect compost pile is like a rung-out sponge moist, but not soggy. Many
composting websites will tell you to water your pile in dry weather and cover it
in wet weather to keep the rain out. But if you maintain a thick outer layer of
carbon-rich material, which helps to prevent rain from soaking into the pile and
moisture from evaporating out of the pile, conditions inside should stay just
right as long as you have the ratio. This is because the nitrogen-rich materials,
which are generally moist, are perfectly balanced with dry carbon-rich materials
when combined in the 30 to 1 ratio.
Always locate compost piles away from
the beating sun and areas where rainwater collects,
6) Stick to the Basics and Stay Away from the Gimmicks
Composting success is a matter of getting the feel of your pile and fine-tuning it
by adjusting the ratio of greens and browns. You don't need books, thermometers,
fancy compost bins, kelp, microbial inoculants, or master composter classes (yes,
this is a thing). You just need a little time to experiment, and the willingness
to let the pile tell you what it needs.
As an example, many composting websites urge you to turn the pile with a pitchfork
to introduce oxygen, which helps the right bacteria proliferate and prevents stinky
anaerobic conditions. However, you can skip this laborious step which also makes
a mess and brings uncomposted kitchen scraps to the surface by using lots of dry,
fluffy leaves or straw ion the pile, which by nature hold lots of space for air.
Rather than store bought inoculants or compost starter,Łsprinkle a bit of finished
compost on at the bottom of the new pile to introduce all the right microbes. They'll
show up anyways if you provide the right conditions, but this gives them a head start.
7) Be Patient
Composting jocks will tell you, as they look condescendingly down their nose, that it's
possible to build a big fat compost pile and transform it into black gold in a few weeks.
That is technically possible, though if speed is your goal be prepared to do lots of
pile-turning and invest in fancy products. It should be noted, however, even once the
pile transforms into a dark crumbly soil-like substance, it takes another six months to
a year for it to matureŁa second, less visible stage of decomposition when other organisms
take over and further refine the compost into something truly alchemical for plants.
If you're not in a hurry (and why would you be?), then relax; stop worrying so much about
whether you're doing it right or not; add more carbon when in doubt; and focus your efforts
on enjoying this miracle of nature.
Now that you've got a grasp on what make great compost, check out our
guide to compost bins to figure out how to house your pile.
A Place to Rot:
The Modern Farmer Guide to Compost Bins
7 Secrets to Perfect Compost
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