Now Is Time For Compost And Composting

November 09, 2006

Fall is here, both by calendar and, finally, with temperatures. And that means, among other things, it is the perfect time for compost and composting.

Backyard composting replicates the natural system of breaking down organic materials on a forest floor. In nature, debris such as leaves, twigs, berries and even fallen trees eventually decompose to become a rich, dark material that looks like the black potting soils sold in garden centers. This decomposition process is basically the same no matter if it takes place in the woods or in a backyard compost bin.

The benefits and uses of compost to soils are to improve quality by adding nutrients, increase aeration, reduced erosion potential, help sandy soils hold moisture, loosen tight clay soils, and make potting soil and mulch for plants.


Compost is the result of activity of billions of tiny organisms utilizing two main chemical components of organic matter - carbon and nitrogen - in their life processes. They consume the carbon for energy and use the nitrogen for growth and reproduction. The portion they can't digest remains as humus, or partially decomposed organic matter.

Microscopic decomposers are mostly single-celled organisms including bacteria, fungi and actinomycetes. Bacteria are considered the most productive. Fungi are like simple plants that lack chlorophyll, the green matter that allows most plants to convert sunlight into plant matter. Actinomycetes produce the grayish cobwebby growths throughout the compost that gives it a pleasing earthy smell.

The physical decomposers arrive in the pile after the lower level decomposers have "worked the material." They grind and chew remaining organic material. Physical decomposers that can be found in a compost pile are mites, snails, slugs, millipedes, sowbugs and earthworms.

Making Compost

Describing how to make compost is like trying to describe how to make soup. There are almost as many recipes as there are cooks. The secret to making good compost is to choose an approach and technique that suits your needs and life style. Your choices will depend on how deeply you want to be involved in composting. Tending a compost pile can take a few hours a year or a few hours a week.

Home composting should be "aerobic" which is up to 90 percent faster than anaerobic composting - and if done correctly, unpleasant odors are avoided. The goal in making good aerobic compost is to achieve a high temperature in your pile to kill or reduce pathogens (harmful diseases, bacteria), weed seed and other pests (flies, plant parasitic nematodes).

Suitable Environment

You can make a suitable "living" environment for beneficial decomposers by monitoring and adjusting: the compost pile size, moisture, particle size and carbon-to-nitrogen ratio.

Pile Size

To reach the higher temperatures needed (120-150 degrees), a compost pile should be 3x3x4-foot minimum. Too small a pile results in low temperatures and slow decomposition.


Compost piles need moisture so decomposers can maintain their activity. Place the pile close to a water source. Apply minimal moisture and give it a squeeze test. It should feel like a wrung out sponge.

Also, positioning your pile in full sun, protecting it from excessive rains, minimizing cool winds and turning it frequently will help!

Particle Size

Good compost materials include products that are thin like leaves or twigs that are cracked or shredded and easy to decompose. The smaller the materials, the quicker the compost will be ready.

Carbon-Nitrogen Ratio

Without getting too technical, I will try too explain the carbon-to-nitrogen ratio. Decomposers need nitrogen to break down carbon materials for energy. The optimum decomposition occurs when the starting mixture ratio is near 30:1.

The simplest way tell you how to achieve an approximate 30:1 ratio is to alternate layers of high-carbon materials, such as leaves and other dry plant debris, with layers of high nitrogen material such as grass clippings, kitchen wastes or manure.

Do not use pet manures, meat scraps, fats or oils, dairy products, diseased/insect infested plants, noxious and perennial weeds as well as plants treated with fungicide within 30 days.

Layer brown, green

Start by spreading a layer that is 3-4 inches thick of coarse, dry brown stuff like straw, or leaves. Top that with 1-3 inches of green stuff. Add 1/4-inch layer of garden soil, moisten the layers and repeat until the pile is 3 feet high.

If sufficient green material is unavailable, supplement with a light sprinkling of nitrogen fertilizer. Use a garden fork or shovel to turn the pile often.

Finished compost

If you turn it at least weekly, in about 6-8 weeks you'll have made a dark, rich compost. You can use finished compost as a soil amendment or apply in tandem with other fertilizer sources. It can be used as a container mix in the following combination: 1 gallon vermiculite, 1 gallon compost (matured), 1 Tbsp. super phosphate - ground, 2 Tbsp. limestone or dolomite, 4 Tbsp. dried manure or blood meal or cottonseed meal.

For More Information

There are a lot of good Web sites on composting. Just go to your Web browser and type in "composting," then select the one you want. Or, call the Victoria County Master Gardeners at the Victoria County Extension office at 361-575-4581.