Feb. 4, 2019
This is Jason Lamb with your Gardening Minute.
Soil Solarization is a process that uses clear plastic mulch that is effective in controlling soil-born pathogens and insects without the use of chemicals or herbicides prior to planting. The plastic sheets allow the sun's radiant energy to be trapped in the soil, heating the upper levels that kill many disease-causing organisms such as insects, nematodes, and weed seeds.
To use solarization gardeners should us clear plastic sheeting of 1.5 mils or greater. The plastic sheet should be placed over a moist area with the edges weighted by soil or rocks during late spring or when outside temperatures reach 75 degrees or greater. Leave the plastic for about four weeks.
The heating effects of soil solarization is the greatest at the surface of the soil and decreases with depth. The maximum temperature of soil solarized is usually from 108° to 131°F at a depth of 2 inches and from 90° to 99°F at 18 inches. Control of soil pests is usually best in the upper 4 to 12 inches.
Most beneficial insects such as earthworm will travel deeper or move out of the area. This technique can also be used on firewood and compost piles to the kill unwanted pests. It is more applicable on small gardens but can be used in between rows on furrow applications.
For more information about soil solarization please contact us at the Cooperative Extension Office at 461-0562. This has been your Gardening Minute with Jason Lamb your Quay County Ag. Extension Agent. Where are programs are open to everyone.
(Adapted from UC Davis Publication 21377 – Soil Solorization)