Knowledge To Grow – Composting Yard Waste

Composting is a naturally occurring process that breaks down organic material into a substance that resembles soil. Finished compost is an excellent soil amendment that improves soil structure as well as adds some nutrients.

All yards and landscapes produce waste from routine plant care such as pruning and mowing.  Turning that waste into compost is a way to reduce the volume of organic waste in a landfill and return it to the soil to benefit growing plants.  Some communities have an established municipal composting facility to manage large amounts of yard wastes and are quite handy for those who prefer to use that service.

Leaving grass clippings on the lawn is an excellent way to reduce yard waste and if it is mowed at the proper height and frequency will not be harmful to the turf.   The clippings will return some nutrients back to the soil, thus reducing fertilizer needs.  If clippings are too heavy or thick then they should be bagged and used as mulch or mixed into the compost pile.  Clippings from a lawn treated with weed killer should not be used as mulch for at least 8 weeks after the herbicide is applied.  The best method of disposal for these clippings is to just leave them on the lawn.

The site for a compost pile should be in a shady area protected from drying winds and is easily accessible.  To make a compost pile, alternate different types of shredded plant material such as discarded garden plants, grass clippings, tree leaves and pruned material in six to eight inch layers.  The smaller the particle size, the faster the organic materials will break down.  Kitchen wastes such as vegetable and fruit scraps, egg shells and coffee/tea grounds can also be added.  Do not add human or pet feces, meat scraps, bones, fat, plants that are heavily infested with insects and disease and weeds with seeds.

Use equal parts by volume of dry and green plant materials in the layers with the base layer consisting of coarser, dry materials such as small twigs. A thick layer of grass clippings can mat easily and prevent the movement of water through the mass during the composting process, so mix them in well with other coarser materials.   Adding a little soil or finished compost to the mix will supply all the microbes needed to get started.  Add water to the compost after every few layers of material and apply as needed after the composting process has begun if rainfall is lacking.  Compost with optimum moisture content should resemble that of a squeezed out sponge.

Nitrogen is needed by the microbes to break down and use the carbon found in organic materials.  The ratio of carbon to nitrogen in the compost pile will affect the rate of decomposition. The ideal ratio is approximately 30:1 and can be reached by combining high and low carbon materials such as dry tree leaves and fresh grass clippings.

Oxygen is another element needed for efficient decomposition.  Turning and mixing the pile at least once or twice a month will add needed oxygen and will bring the outer materials to the center for heating and faster decomposition.

Compost can be used as an organic media in potting soil or for starting seeds of garden plants, as a garden mulch to conserve soil moisture and to cover seeds as they are planted to prevent crusting in heavy soils.

As always, Happy Gardening!

More information about gardening and related subjects is available online. The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co., 636-2111 in Noble Co., 925-2562 in DeKalb Co. and 668-1000 in Steuben. Co