How to Kill Weeds With Plastic Sheeting Before Planting a Garden

Use plastic sheeting to suppress weeds in a large garden space.

Plastic sheeting is a type of synthetic mulch often used by gardeners to suppress weeds and retain moisture in the soil. Landscape fabric is a type of plastic sheeting that is specifically designed to allow air circulation and water flow and is considered the best choice for using in an established garden. However, for suffocating weeds and their roots, non-breathable plastic films are more effective. In addition to smothering weeds, the anaerobic conditions under the sheeting produce methane gas which is toxic to the weeds.

Things You'll Need

• Scissors
• U-pins
• Hammer
• Mulch

Instructions

1. Unroll the sheeting onto untilled soil and unfold it if it is folded. Cover the entire garden bed at once, or work in sections if you are killing weeds in a large space.

2. Cut the sheeting to the proper size. Do not let non-breathable plastic sheeting overlap into areas where desired plants are growing.

3. Insert U-pins into the corners and edges of the sheeting to secure it to the ground. Push or hammer the pins through the sheeting and into the soil.

4. Cover clear sheeting with additional mulch for the best results. Spread a 2-inch layer of organic or inorganic mulch over the plastic sheeting to completely block weeds from their light source. A mulch layer is not necessary if you are using black sheeting.

5. Pull up the U-pins and remove the plastic sheeting and additional mulch before the growing season. Prepare the garden soil for planting as usual.

Tips & Warnings

• Apply plastic sheeting in the late summer when weed growth is high and remove it the following spring. Or apply it early in the spring, several weeks before you wish to plant your garden. Covering a garden plot when weeds are dormant will not be helpful. Plastic sheeting is effective for killing existing weeds, but may not destroy weeds seeds that already linger in the soil. Regular weed maintenance of your garden site will still be required.

References

• Missouri Botanical Garden: Mulches
• Ohio State University: Controlling Weeds in Nursery and Landscape Plantings

Resources

• Texas A & M Extension Service: Seasonal Color Care and Management