How to Use Black Plastic to Sterilize Soil
- 1). Till the area of the garden you need to sterilize to a depth of 12 inches. This will bring weed seeds closer to the surface, better ensuring that they will be cooked during solarization.
- 2). Water the soil deeply so that the top 12 inches are thoroughly moist. This will help with the heating process, as the water conducts heat deeper into the soil.
- 3). Cover the entire area with thin black plastic sheeting. Hold down the edges of the sheeting with large rocks or bricks to ensure that it will not blow up and allow cooler air underneath. You must seal all edges completely for the solarization to work.
- 4). Check the soil every two weeks to ensure that it is still moist; if necessary, lift the plastic briefly to moisten the soil again. Leave the plastic in place for at least six weeks, up to eight weeks if the temperatures are not steadily above 70 degrees F during the process.
- 5). Remove the plastic and mix compost or humus into the soil before planting to freshen the fertility of the soil with healthy organisms.