A compost pile is as easy as piling up kitchen scraps and brown yard debris, then letting it rest and decay. This could take 2 years.
To make things go a little quicker (one season), you need to contain it on at least 3 sides and provide aeration.
A simple structure may be made from two rows of concrete block with a vertical extension made from 2 x 4’s and wire fencing. Turn it and you will create more heat to decay the matter quicker. All composting methods simply need to meet the needs of the microorganisms to break down the organic matter into humus.
Those needs are:
- Air
- Moisture
- Energy food(carbon)
- Protein food(nitrogen)
Materials needed:
Air can be easily provided by turning the pile. Other ways of aerating the pile by layering perforated pipe between the layers of materials. Building a bin with a bottom lined in hardware cloth raised a foot or so off the ground. Bins made with open fencing on the side will provide enough air if poked with pitch fork to make air pockets from time to time.
Moisture should be added so that pile is damp like a moist sponge. Too little moisture slows down the decomposition and too much moisture can encourage rot in the pile evident by a foul smell. In wet areas, select a site with good drainage. In arid climes, you may even dig a shallow pit to ensure enough moisture.
Carbon materials provide the decomposers energy and nitrogen materials for growth. The ideal carbon/nitrogen ratio is about 25:1, with carbon be the higher. Carbon materials are in general the brown and dry materials such as leaves, pine needles, straw, cornstalks and sawdust.
Nitrogen materials tend to be green and succulent such as manure, grass clippings, alfalfa meal.
Kitchen garbage like veggie trimmings, eggshells, coffee grounds and manure mixed with bedding, already have the ideal C/N ratio. Layering kitchen scraps with dried leaves or garden debris will keep the flies and critters away and foul smells.
Carbon materials contribute mass to the pile and contribute to the formation of organic gums in the humus. Nitrogen is needed to stimulate microbes to reproduce as rapidly as possible. Even low nitrogen pile will break down over time but they will not reach the temperatures needed for hot composting. If there is too much nitrogen in relation to the carbon, the nitrogen will be lost as ammonia and smell like it. If this happens, add more carbon materials and aerate.
During the formation of the pile, add some organic fertilizer and soil to keep microbial activity high. Also, urea helps to activate the pile, so if it’s private enough, pee on it.
Warmth is needed for the pile to “cook”.
There are 2 types of compost methods:
COLD compost piles must be at least 55 deg. F for bacteria to be active. If properly built to provide a mass area of at least 3 cubic feet, the pile’s interior should stay above that temp even if freezing. Northern gardeners sometimes insulate the pile during winter with hay or leaves, to keep it cooking over the time. A small pile should be done by spring if kept covered. Easier to maintain, a cold pile doesn’t need to be turned. It doesn’t heat up enough to kill insects and pathogens, but it also doesn’t kill the good disease fighting microbes. You can add materials a little at a time over the season and then let sit while you start a new one. Usually three piles at different stages will give you a consistent supply. Easier to keep in balance then hot method, needs equal amounts of carbon and nitrogen, and wet and dry materials.
HOT compost piles need to be 140 deg. F. For best heating a pile 4 or 5 cubic feet works best. They need to be turned frequently to keep the heat up. When turning the pile, shovel the materials from the outside to the inside, as that is where the highest temps are. Advantages are that it finishes in a couple of weeks due to heat and kills most weed seed and pathogens.
Shortcomings are that it must be monitored closely with careful control of moisture and C/N ratio. It must be built all at once to start everything all together. Kills good disease fighting microbes.
You can buy inoculants (microorganisms to get the composting started) but you can do it yourself by adding a little topsoil or finished compost over each layer, which both already have a good blend of microbes working. Kind of like making Amish Friendship Bread!
Fungi are also an important player in the compost pile and in the garden. Fungi hold soil together in small clumps called aggregates. These aggregates keep essential particles, such as carbon and minerals from leaching out, thus making them available to plant roots.
Compost is finished when it’s dark, rich, crumbly humus. You may have big chunks to be picked out. These can be used as “starter” for the next pile.
DO compost:
- Fruit and Veggie scraps
- Coffee grounds and teabags
- Eggshells crushed
- Nut shells
- Wood ash or charred bits
- Sawdust from untreated wood
- Newspaper
- Grass clippings
- Straw
- Leaves
- Yard and garden trimming
- Barnyard animal manure
DON’T compost:
- Dairy products
- Fats and oils
- Meat
- Pet waste
- Disease or insect ridden plant material
- Plant material treated with chemicals