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Yes, but always read the pesticide product label to be sure the product has been approved for this use. Sometimes, after finding the perfect spot to plant a garden, we realize we need to get rid of weeds that have grown all over it. To get this done we may choose to use a weed killer.

All weed killers are not the same

A weed killer is a pesticide that kills plants, also known as an herbicide. Selective herbicides only kill certain plants and do not harm others. Nonselective herbicides kill any plants that they touch. There are many different weed killers available and their risk to people can vary from low to high. Some weed killers are suitable to use for preparing the soil, and some are not. It is important to read the label to make sure it clearly states that the product can be used to prepare a garden plot.

Toxicity to new plants

In the soil, microbes and water can break down weed killers. The product label will tell you whether or not you have to wait before planting new seeds or starts, and how long to wait. The waiting period may vary for different vegetables, for example: you may need to wait days to plant peppers and weeks to plant tomatoes. Some weed killers last so long that they shouldn’t be used for garden bed preparation. The waiting period before planting depends on the weed killer you use.

Toxicity to plants nearby

Some weed killers are likely to stay put, based on their chemical properties. Other weed killers are likely to move down into the soil, or up into the air, based on their chemical properties. Following the label will protect untreated plants nearby.

Other alternatives

Depending on the plot size, timing, and other factors, you may be able to use an Integrated Pest Management approach, which involves non-toxic weed control techniques, like hand weeding. Consider contacting your local Cooperative Extension Service for additional advice about preparing the soil before planting a garden.

Last updated April 15, 2024

If you have questions about this, or any pesticide-related topic, please call NPIC at 1-800-858-7378 (8:00am - 12:00pm PST), or email us at npic@ace.orst.edu.