Safe steps for using cow manure in home gardens

Composting has many advantages over chemical fertilizers. First, gardeners can utilize their yard waste--leaves, grass clippings, vines and stalks--as well as vegetable peelings and straw to form the compost foundation. To aid in chemical breakdown, some gardeners add cow manure to supply the needed nitrogen, but there are some precautions to take before doing so. "Cow manure may contain E. coli, which we know is a dangerous bacteria that can cause severe illness and even death," says Dr. Jodie Pennington, dairy specialist with the University of Arkansas Cooperative Extension Service. "Generally, we only think of E. coli when consuming beef, but the bacteria itself can remain in manure and spread to what it touches." Fortunately, composting provides a way to address this concern. When the correct blend of carbon, nitrogen, moisture and oxygen are available, beneficial micro-organisms will actively compost, that is decompose the manure and carbon material. Under ideal conditions, the temperature of the compost pile will rise to 130 degrees Fahrenheit, or more. If maintained for several days E. coli and other harmful bacteria are killed. This heating process should also help to kill weed seeds. "When the temperature starts to drop, the pile should be turned over and mixed to re-aerate it so that the active composting will continue," says Dr. Karl VanDevender, Extension engineer. "If desired, the pile can be left alone for several months to finish decomposing at a slower rate. When completed, the finished compost will have a lower nitrogen concentration than the original manure. It will then be less likely to burn or kill vegetation." To use the compost, till it into the soil prior to planting or add it as fertilizer after seeds have been sown. While active composting kills harmful bacteria, it is still recommended that you wear gloves when handling compost containing cow manure as well as washing up thoroughly afterward to avoid cross-contamination of surfaces or food. "Especially important is to thoroughly wash vegetables or fruits grown in cow manure compost," Pennington explains. "A good rule of thumb is to do it before taking it in the house as well as prior to preparing a meal." For more information about food safety and nutrition, visit www.uaex.edu, or contact your county Extension agent. The Cooperative Extension Service is part of the U of A Division of Agriculture.