University of Vermont Extension 
Department of Plant and Soil Science

Fall News Article

COMPOST, DON'T BURN!

Dr. Leonard Perry, Extension Professor
University of Vermont
 

You may like the smell of burning leaves, but did you know you were sending an excellent soil conditioner up in smoke? Instead of burning leaves or stuffing them in garbage bags for the trash haulers to take away, compost them.

Compost improves garden soil by increasing its organic matter. This, in turn, improves soil drainage. Organic matter is especially beneficial in heavy clay or light, sandy soils. Organic matter reduces soil crusting and helps soil hold water and nutrients. The compost also supplies a small amount of nutrients. Compost can be used as a mulch around plants, too. Mulch helps conserve moisture as well as reduces frost heaving.

Microorganisms are what decompose materials to make compost. To do their work they need carbon sources for food, and nitrogen for proteins. They are most effective when the ratio of carbon to nitrogen is an average of 30 to one, by weight. You donít need to weigh what you add to the compost pile, just be aware of approximate amounts youíre adding.

In general, course woody material (sawdust, leaves) is high in carbon. Moist, dense material (manure, grass clippings) is high in nitrogen. Too much carbon materials and the compost pile will decompose slowly. Too much nitrogen and you may smell ammonia gas.

To compost leaves, alternate leaves with layers of soil or manure. Make layers of leaves six to 12 inches thick, layers of soil or manure about one inch thick. To hasten decomposition, shred leaves first with a rotary lawn mower or shredder.

For each bushel of organic material, add one cup of complete fertilizer such as 10-10-10 and two-thirds cup ground limestone. Moisten each layer. Finish the compost pile by slightly rounding the top to help the pile hold water. Cover with an inch of soil.

Next, cover the compost pile with plastic. Hold the sides in place with wire, concrete blocks, or boards. Turn the pile every few weeks throughout the fall, adding moisture during prolonged dry periods. Both will help speed decomposition and make the final product more uniform. Compost piles are simple to do, but it does take time for the process to work. If you start a compost pile this fall, don't expect to use it in the spring. However, it should be ready to spread next fall.

Keep in mind that you are not limited to leaves for composting. You can use any plant material that's not diseased, doesn't contain mature weed seeds, and hasn't been treated with pesticides. In addition, non-meat kitchen scraps can be composted.

Plant materials and products that are easy to compost, and generally decompose most rapidly, include egg shells, coffee grounds, pine needles, fruit peels and rinds, paper, sawdust, straw (not hay, as hay often contains weed seeds), vegetables, tea bags, wood ash, and wood shavings. Materials that are slow to decompose and may take two years to break down include coarse wood chips, branches, corncobs and corn stalks, and nut shells. Breaking these materials into smaller pieces, and adding high nitrogen materials will speed up their composting.


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