How to Sterilize Soil

Soil is the foundation of your garden. If there comes a day that your soil is besieged by nematodes or, perhaps, an invasion of noxious weeds, you may wish to start over with new soil. Instead of digging out all the existing soil, disposing of it and replacing it with fresh, you can sterilize your soil using the energy of the sun. This is a last resort and should only be used in extreme circumstances.

Things You'll Need

• Bricks
• Clear Plastic Sheeting
• Compost Makers
• Garden Hoses
• Rototillers
• Shovels

Instructions

1. Remove most of the weeds and large debris from the soil you plan to sterilize. For best results, start the process in the summer when the temperatures are soaring.

2. Water the plot well. Ideally, the water should penetrate into the soil at least 18 inches.

3. Cover the entire area with clear plastic sheeting. Use bricks or boards to hold down the sides.

4. Allow the plastic to stay in position for at least four weeks. You may see weed seeds germinate under the plastic, but they won't live long in the high temperatures.

5. Remove the plastic sheeting, turn the soil to a depth of 18 inches with a shovel or a rototiller. This step will bring any weed seeds, bacteria or nematodes to the surface.

6. Water the entire area one more time and replace the plastic.

7. Let the plastic stay in place for another four weeks. Soil solarization will kill everything in the ground including weed seeds, nematodes, earthworms, and both good and bad microbes and bacteria.

8. Remove the plastic; incorporate some organic compost into the soil to reintroduce beneficial microbes and bacteria; water and plant.

Tips & Warnings

• This process works best for garden beds in full sun.