Last week I talked about how getting ahead on learning organic farming would give you advantages in a community. In this week’s series of articles, I’ll teach you some of the basics you’ll need to know to get started. This week’s topic is on compost.
Industrial agriculture requires a massive infrastructure and lots of oil. One of the problems of peak oil is that we could face a food crisis due to a lack of chemical fertilizers that are derived from petroleum. Even the standard home gardening books teach the use of chemical fertilizers.
The heart of every organic garden is the compost pile just like the heart of industrial agriculture is the fertilizer factory. Compost is the rotted remains of plants. Put another way, compost is plant food. Nature makes compost every year when the leaves fall.
Composting is quite easy, though a lot of books make it tremendously complicated. There’s a lot of conflicting information out there about what can and can’t be composted, how long it needs to be composted for, should it be tumbled, left alone, given additives, etc. Before you can assess a method, you need to know the chemical basics behind compost.
For the composting process to work, four things are needed: carbon, nitrogen, oxygen, and water. If these are properly balanced then the pile will work. If they are out of balance, then the process will slow down or stop. If they are too far out of balance then there will be problems. Fortunately, there’s a wide buffer before things go wrong.
Carbon
Carbon is in all organic material, and it is what is most needed in the pile. Composting books will call carbon-rich material “browns”. These are things like leaves, dried grass, wood chips, saw dust, peanut hulls, and other dried organic material. Try to avoid material that has seeds. If you have too much carbon in your pile, then it won’t break down. Add more nitrogen to remedy.
Nitrogen
“Green” material contains nitrogen. Kitchen scraps, animal wastes, green lawn clippings, green leaves, coffee grounds, even seaweed can be used as green material. If you have too much nitrogen in your pile, then your pile will start to stink like ammonia, look slimy, and it won’t work efficiently. Add more carbon.
Water
Water is essential to all life. If your pile is too dry then the microbes will go dormant. If it goes dry for too long you’ll end up with ants or termites in your pile. If it is too wet then nutrients will be washed out. Ideally you should be able to pick up a handful of your material, squeeze it, and only get a couple of drops out. Few people get that precise though. I just water it until I see water coming out the bottom and check the inside of the pile every couple of days. The center and bottom of the pile is where most of the action takes place, so don’t let the outer dry shell deceive you. Pull back the top part of the pile to check for water.
Oxygen
Oxygen is also required for a pile to function. This is why turning a pile is so important. It reintroduces oxygen. It also breaks up material that may have matted with time. If oxygen can’t get to the pile, the anaerobic parts will start to build up too much nitrogen and stink, or if the nitrogen is used up then it will stop composting.
What Can’t Compost (Easily)
Everything will eventually compost. However, for gardening purposes there are a few things that you’ll want to avoid for the home garden:
- Big lumps of carbon (branches, large wood chips, pits): Will take more than a year to break down, but won’t hurt the pile. Can tie up nitrogen. May have to sift compost each season.
- Meats, bones, fats, oils: Attracts animals who will see your pile as a source of food. Fats and oils also block basic compost reactions.
- Wastes: Fresh disease-free urine is safe, though very high in nitrogen. I use it myself to break down wood chips. You can also dilute it with 5 parts water for your pile. Fresh manure is also very high in nitrogen, except for rabbit. Human manure can be composted safely, but requires special handling to kill off human pathogens. See “The Humanure Handbook” by Jenkins for (very) detailed information.
How To Build Your Most Basic Compost Pile
Clear a patch of ground about 4’ by 4’. Fence it if you want. Now there are a lot of books out there that tell you to layer your components very carefully, but if you’re going to be mixing the pile in a couple of weeks it’s not really necessary.
Take your brown carbon material and shred it to 0.5-1.5” pieces. This is important! The finer the pieces the faster the process, though pieces too fine will mat. Use a sharp shovel. Put the shreds in the spot. Take your green material and shred it up a little. Mix it with the brown stuff. Ideally you’ll want a finished pile that’s at least 3’ high. A pile that’s too small will also be slow.
Water it until it is like a damp sponge. Check it every couple of days for water, and mix it up every couple of weeks or so. Add more material as necessary. If you like, sift it when you turn it on ¼” hardware cloth and set the finished compost in a separate area to continue breaking down until you need it.
That’s really all there is to it! If you do this in fall you’ll have compost by spring.
Is it possible to make it faster? Yes, but the faster you try to speed it up the more attention you’ll need to give it. The University of California has a method that can make compost in two weeks at http://vric.ucdavis.edu/pdf/compost_rapidcompost.pdf.
