Q: I hear so much about compost in gardening magazines and see it next to the bags of peat moss and fertilizer at the store. What is it?

A: Compost is any dead organic matter at varying stages of decomposition. The word “compost” is derived from the action of decomposition. Standardization of making compost and the process of composting is something that is not strongly regulated in the U.S. because of the varying ways to create it. Composting is a relatively new science, yet is an ancient art.

Nature has been decomposing organic matter since there has been vegetative matter on the planet. The dead organic matter in compost is being eaten by bacteria, fungi and a host of other micro- and macro- organisms, who use the energy to continue their role in the web of life. Eventually the decayed material breaks down into the basic elements from which it was made.

Our soils are fractions of sand, silt, clay, organic matter and air. When we add compost to our soil we literally enliven it with microbes. These microbes attract macrobes that we see in healthy soils, such as worms, spring tails, sow bugs and millipedes. These critters have an important role in decomposition, air management and nutrient cycling in the soil. These processes will continue if we “feed” the soil with organic matter and water.

The actions and reactions of all the organisms in this complex cycle work to improve soil structure. Adding compost increases soil water holding capacity and also provides plant nutrients. Healthy soil grows healthy plants, which, in turn, feed humans and animals.

Commercially sold compost you see in stores is not regulated as fertilizer, so look for the U.S. Composting Council Seal or the Rocky Mountain Organics’ Council literature that will better describe what you are buying. This literature can be found at www.manuremanagement.info under the compost link.

If you’re looking to be more sustainable, buy local and in bulk, which can be far less expensive, though not as convenient. Also, develop a relationship with your supplier. Suppliers should always be forthcoming with how they make their product and have compost test information on hand.

To be even more nature friendly learn to make your own by attending classes sponsored by city or garden clubs, or following instruction from CSU Cooperative Extension Fact Sheet 7.212 “Composting Yard Waste.”

Gardening and Insect Fact Sheets are available on-line by clicking HERE.

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This page updated:  April 13, 2007