Gardening Articles: Landscaping :: Yard & Garden Planning

Compost 101

by National Gardening Association Editors


One of the best natural fertilizers and soil builders is available free. You make it yourself and solve some environmental problems at the same time. It's compost. Good gardeners have been making their own compost for a long time, but it has recently been "discovered" as one solution to the problem of our shrinking space in landfills.

Many communities now forbid yard wastes or charge a premium for taking them. Community composting has arrived on the scene, and you can also do it in your own backyard. Leaves, grass clippings, and even vegetable wastes from the kitchen are the building blocks of compost.

Making compost is simple and inexpensive. It is a little like making a lasagna -- a layer of this, a layer of that and then let the whole thing cook until it's done.

For equipment, you can use a homemade container made from welded wire mesh, concrete blocks, or wooden shipping pallets -- anything that will allow you to form a pile three to five feet across and not more than five feet high. Or, you can use a purchased compost bin. Many of these contain features that making turning the compost easier, speeding the decomposition process.

The recipe for compost is air plus moisture plus layers of waste materials like leaves, grass clippings, kitchen scraps (not meat or bones), weeds pulled from the garden, and so on. These things dumped into a bin will decompose slowly over time -- and that might be sufficient.

However, you can make compost in as little as a few weeks by constructing a pile or using a bin that heats the materials to more than 140 degrees, killing any weed seeds or harmful bacteria in manures. These piles are made by layering materials high in carbon (leaves, for example), with materials high in nitrogen (manure, alfalfa meal, cottonseed meal).

The classic organic gardener's recipe for compost calls for a layer of vegetable matter about six inches thick, a layer of manure about two inches thick, then a thin layer of soil with ground limestone added. This compost lasagna is repeated until the pile is three to five feet high. A little depression is made in the top and it is watered. Serious composters often have several bins in a row where they collect and stockpile materials.

The smaller the pieces, the faster they will be broken down by the many types of bacteria that will go to work. A chipper or grinder is becoming an increasingly important piece of equipment for shredding soft materials for composting. Coarse, woody materials are also chipped and used as mulch on flower beds and around landscape plants.

In about two weeks, the bacteria will have reduced a lot of material in the pile to compost and caused it to heat up, but they probably will have run out of oxygen. The pile now needs to be turned to be aerated.

If you used a wire mesh, you can simply stand on top of the pile and pull it straight up and off. Then set it to one side and turn the pile into it. Depending upon your setup, you can turn the material into an adjacent bin or turn it within the bin itself. A three-side bin makes this easier.

Commercial compost machines available in garden centers often make this process easier by putting a drum or container on some kind of turning device.

In another week or two, the compost can be worked into your soil. Any remaining large lumps can be recomposted. Things like broccoli stalks break down faster if they are pounded with a mallet to soften them up.

There are as many variations on the composting theme as there are gardeners. For example:

  • Keeping a supply of red wiggler earthworms in a container in the basement to compost kitchen wastes.
  • Blending small amounts of vegetable wastes in a blender and adding it to houseplants.
  • Simply burying kitchen wastes in flower or vegetable garden beds.

Vegetable kitchen wastes, including coffee grounds and egg shells -- even hair, feathers, wood ashes, ground stone and shells -- can be composted along with yard wastes. Items that should be kept out of compost include meat and bones, large amounts of sawdust, pet manure and, of course anything metallic or plastic.

When the compost is done, it can be turned into the soil or sifted through a screen of hardware cloth and used to pot houseplants. Composting is one of the most direct and beneficial forms of recycling around.

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