Using nature to improve the soil
There are many unseen enemies of the casual gardener lying beneath the surface of the lawn and garden. Insects and disease are two of the main culprits and they can destroy a vegetable crop in a very short time. Most gardeners know that diseases can remain in the soil for several years. If you lost a crop of tomatoes because of a virus or fungal problem last year, the chances of you losing this year's crop is very high if you plant in the same area. Insect damage may also be a problem. Plant parasitic nematodes are small microscopic roundworms which live in the soil and attack the roots of plants. Crop production problems induced by nematodes therefore generally occur as a result of root dysfunction, reducing rooting volume and utilization efficiency of water and nutrients. Moving the garden or replacing the soil can be an expensive option. Today, we will offer an inexpensive but somewhat labor intensive alternative plan to eliminate insects and disease.
Soil solarization is a relatively simple method of sterilizing the soil and eliminating insects, diseases and weed seeds. It will take some light labor and some of natures energy but the results will be worth the effort. The only product that you will need to purchase is some clear plastic sheeting approximately two mills thick. One mil is too flimsy and five mills is too opaque and will reduce sunlight penetration.
The first part of the job is the toughest and the amount of time required is dependent on the size of your garden. The soil must be tilled to a depth of six to eight inches. We suggest a tiller rather than a cultivator to make the job easier and more efficient. You will want to expose and weed seeds, insects, rocks and other debris that may be present. After the area is tilled, rake the exposed weeds and debris and dispose the excess. Then do your best to level the area either by raking again or dragging with a small garden tractor. Once the soil is prepared, it is now time to solarize it. Solarization is heating the soil using the sun's energy. A clear layer of plastic sheeting will intensify the sun's rays and heat the soil to 4" between 140 and 150 degrees Fahrenheit. The best time of the year to do this procedure is during our hottest months of June, July and August although May and September will also work. Weed seeds, nematodes and plant diseases should die at these extreme soil temperatures although some nematodes living deeper than 6" may survive. Their populations will still be reduced to manageable levels.
Before laying the plastic sheeting, water the soil thoroughly to a depth of three to four inches. Soil insects are more sensitive to moist hot soil than dry soil. Clear plastic works better than black plastic since it allows the sun's rays to pass through and heat the soil. Black plastic absorbs the heat and keeps it on the surface. Lay the plastic as flat to the soil's surface as possible. The difficult problem now, is keeping the plastic in place. The edges of the plastic should be weighted down with soil, lengths of pipe, logs or any other method that will keep the plastic in place. A little wind can get under the sheeting and turn it into a sail.
Once secure, the sheeting should remain in place for about six to eight weeks. The super heat should destroy any diseases, weeds or insects and make the area a perfect place for a winter or spring garden. For more information on soil solarization, visit www.ehow.com/how_4037_solarize-soil.html.
The Master Gardener's "Lunchbox Lectures" continue to be a great success. Last week's discussion on plant foliage was highly attended and Pam Glogowski shared her exceptional gardening skills with the attendees. The next lecture will be on August 16, 2010 at noon in the Clemson Extension Center, 1555 Richland Ave., East. The topic will be "Irrigation" and the speaker will be Chris Randall, the current President of the CSRA Hydrangea Society and a Master Gardener.
The Master Gardeners will be at the Farmers Market on Aug. 7 to answer lawn and garden questions from the public. Stop by and try to stump the experts with a weed or strange flower. Please leave the poison ivy at home.
Bill Hayes has been in Aiken since 1982 after moving from Chicago, Ill. He was in the chemical process industry for more than 40 years before retiring in 1999.