GARDENING101: Compost

The Rev. Dana Prom Smith, S.T.D., Ph.D. (3/27/09)

As a boy during the early 1930's, I often went with my father in his 1933 Franklin into San Fernando Valley to fetch large burlap bags of oak leaf mold for his camellias and roses. San Fernando Valley then was a land of farms and ranches dotted with a few small towns. Along with selling fresh fruits and vegetables at roadside stands, the farmers often sold oak leaf mold they'd gathered underneath their live oaks trees which were perpetual composting piles.

Composting is recapitulating the wisdom of those live oak trees, taking the things we no longer use, dropping them and letting them decompose into useful nutrients for the garden. With the exceptions of meat, oil, metals, pet and human feces, and plastic, almost anything organic can be used in a composting pile although some things decompose faster than others. Pieces of wood, tree branches, large stems, avocado and citrus skins, fruit pits, and newly dropped pine needles take a long time decomposing.

Fundamentally, composting is a disintegration of organic material, decay and rot, into nutrients for plants. In addition to organic material, aeration and oxygen are necessary. Aeration is a fancy latinate word for airing, turning compost with a pitch fork so that air and oxygen can get into the pile to fuel the microbes. Also, aeration removes heat, water, and other gases from the pile.

In addition to oxygen, compost requires heat, and, generally speaking, the most efficient temperature for composting is around 110º F to 150º F. The higher the temperature the more pathogens, diseases, weed seeds, and insect larvae are destroyed. Thermometers are available. A hand will do, stuck in the compost. If it's too hot for comfort, turn it with a pitch fork. No big deal.

Sometimes the compost pile heats up to 160º F. When that happens, the heat may cause the microbes to go dormant or die which means that the composting process will stop because the microbes do the decomposing. They're the worker bees in composting.

Heat as well as moisture can be controlled with the pitchfork. The most useful instrument for moisture assessment is the human hand. If
it's waterlogged or dripping, it's too wet. The easiest way to find the proper moisture level is to squeeze the material in a bare hand, if it doesn't drip but feels moist like a wrung out wash cloth, the material has the right moisture. Hands can always be washed. Besides, if people don't like to get their hands dirty, they shouldn't be gardening and are probably avoiding life anyway.

If the material is too dry, add a little water while turning the material. If it's too wet, add dry material while turning the pile.

As with cooking in the kitchen, cooking compost in the backyard requires the right recipe, a 30:1 ratio of carbon to nitrogen. When the ratio is less than 30:1, such as 15:1 in table scraps, the material is called green and more than 30:1, such as 80:1 in old leaves, it's called brown. Examples of brown materials are dry leaves, sawdust, bark, straw, dry bread, egg shells, and shredded paper, of nitrogen materials vegetable and fruit scraps, tea leaves, coffee grounds, grass clippings, and manure. Since almost all organic material contains both carbon and nitrogen, probably the best measurement at the composter is 3:1 of brown to green. A good measuring instrument is a shovel.

If nothing happens, as in no heat in the compost, that means too much carbon material. If it begins to stink and go putrid, that means too much nitrogen material. If nothing's happening, a trip to a local coffee house to fetch a bag of coffee grounds will help the pile to become a microborama. If the bin begins to stink, throw in some sawdust or dried bedding from a horse stall. When using manure, as in wine, use only vintage manure, never serving manure before its time.

The equipment needed is a pitchfork, a hand, and a shovel along with a bin. The material needed is water, air, and organic material. In a few months, compost. Décadence joyeuse.

Copyright © Dana Prom Smith 2009