How to Kill Grass for a Garden Site

Kill grass with little effort, and then install a new garden bed.

When starting a new garden bed or adding landscape elements, it is often necessary to kill off the existing grass in the area. Using the heat of the sun to do so renders grass and weed seeds sterile, eliminating them as a future pest in the bed. Clear plastic traps the heat of the sun under it, killing grass roots, seeds and any pathogens residing in the soil. The process, called solarizing, takes two or more months to complete, so start the summer before you need the grass cleared.

Things You'll Need

• Lawn mower
• Rake
• Power tiller
• Shovel
• Wheelbarrow
• Plastic sheeting

Instructions

1. Mow the area prior to solarizing the soil. Cut the grass using the lowest blade setting available on your mower, and rake up any cut grass blades.

2. Till the top 6 inches of soil, turning the remaining grass and roots in to the soil. Use a power tiller to speed up this process.

3. Dig 3- to 5-inch trenches around the perimeter of the area you are solarizing. Place the removed soil into a wheelbarrow.

4. Soak the soil with water until the moisture has leached down into the soil bed at least 12 inches. Moisture in the soil conducts the heat through the entire area, ensuring buried grass roots and seeds are killed.

5. Lay a sheet of clear plastic over the solarization area, smoothing it down so it is in contact with the soil over the entire area. Push the edges of the plastic into the trench, and refill the trench with the soil in the wheelbarrow. This anchors the plastic down.

6. Remove the plastic just prior to planting your beds, either in the fall or the following spring. The plastic prevents invasive weeds from growing in the cleared area.

Tips & Warnings

• June, July and August are the hottest months in most areas, and the prime period during which to solarize the soil.

• Do not till more than 12 inches into the bed after you are finished solarizing it. Seeds and disease organisms that are more than 12 inches beneath the surface are not affected by the solarizing process.

• If you don't solarize after tilling, the grass will root itself into the bed again and later grow back as weeds in the garden.

References

• Oregon State University: Early Summer Is the Best Time to Begin Solarizing Garden Soil