Composting recycles yard waste

Richard Bogren, Gill, Daniel J.  |  5/1/2012 9:10:07 PM

For Release On Or After 05/11/12

By Dan Gill
LSU AgCenter Horticulturist

You can recycle yard waste back into the landscape through the process of composting, which benefits your garden, your budget and the environment. Compost is used primarily in bed preparation to improve the soil and can even be used in preparing potting mixes. Partially composted material can be used as mulch. And because homemade compost is free, it helps reduce the cost of gardening. (That means more money left over to buy plants.)

Returning these organic materials to the garden maintains natural biological cycles and is an ecologically sensible means of recycling organic waste. It has never made sense to me how people will pile up their leaves and grass clippings in bags on the curb to be hauled away to rapidly filling landfills and then go out and buy peat moss that has been dug up and shipped down here from Canada.

Compost piles should be located in a convenient but out-of-the-way location. A source of water nearby is helpful. Avoid locating the pile up against fences or other structures made out of wood because the constant moisture can cause decay. Make the pile about 3x3x3 feet to 5x5x5 feet in size. Anything smaller, and the pile will not decompose as well, and larger piles are more difficult to work.

You can create compost simply by piling organic matter and allowing natural decomposition to take place. (This is sometimes called passive composting.) There is nothing really complicated about it, although using this method requires patience. Depending on circumstances, it may take six to 12 months for the organic matter to fully compost.

Although you can compost just by stacking organic matter in a pile, most gardeners prefer to enclose the pile in a bin. A number of commercial bins are on the market, or you can make your own very easily. A 15-foot-long length of wire fencing material bent into a circle and fastened with a few pieces of wire is inexpensive and easy-to-build and works well. Avoid using untreated wood to build a bin because termites may become a problem.

Typically, composting uses various techniques to speed up the natural breakdown of yard waste. It’s important to remember that raw organic material is converted into compost by the action of fungi and bacteria. In active composting, we do things to make these organisms work faster and more efficiently.

These fungi and bacteria require adequate nitrogen, oxygen and moisture to decompose organic matter rapidly. The composting process attempts to provide these requirements, and the better job you do, the faster the process will occur. Shredding or finely chopping materials also greatly speeds up the process.

As the microbes decompose the organic materials, temperatures within the pile may approach 160 degrees at the center. When properly done, this process produces a rich, earthy smell, not the bad odors many gardeners fear will occur. In addition, properly maintained compost piles will not attract and harbor vermin such as rats.

Try to include a variety of materials to encourage rapid decomposition. The more types of acceptable materials you add, the better the composting process will generally be.

Brown materials, such as dry leaves or chipped branches and stumps, are relatively low in nitrogen. Adding a commercial fertilizer or an organic fertilizer (such as blood meal) that contains nitrogen encourages rapid, thorough decomposition when these types of materials provide the bulk of what is being composted. Apply a light sprinkling of fertilizer over each 8- to 12-inch layer of organic matter as the pile is built. If the pile is mostly green matter, turn it weekly to keep it loose and oxygenated.

Organic materials that can be used for composting include fallen leaves, grass clippings, shredded hedge clippings, raw vegetable and fruit trimmings and coffee grounds from the kitchen, dead houseplants and old flower arrangements. Manures, such as cow, horse, rabbit or poultry, make excellent additions to the compost and are relatively rich in nitrogen.

Never put cooked foods, grease, meat, seafood scraps, fat, or dog or cat droppings in the pile.

Bins that enclose compost piles need sides with a lot of ventilation openings to allow air to move in and out to provide adequate oxygen. Turning the pile occasionally is labor intensive, but it also ensures the pile is well aerated.

During dry weather it may be necessary to water the pile to maintain adequate moisture; dry organic matter will not decompose. The pile should stay moist, but not constantly soggy. A pile that stays too wet does not contain enough oxygen and may produce sour odors. If this happens, turning the pile will correct the problem.

As materials compost they lose more than half of their volume. When compost is ready for use, it should be dark brown and crumbly with much, or all, of the identity of the original material lost. The time it takes to finish varies, depending on the materials used, how finely they were chopped and good maintenance of moisture and oxygen. Two to six months is typical, but the final result can occur much faster.

Rick Bogren
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