Flame weeding

Flame weeding is an approved organic method of weed control.

Flame weeding: Flame weeding

Flame weeding is a weed control method where intense heat from a controlled flame is directed onto small plants to kill them. It is an approved organic weed control practice and equipment has been developed for application in field crops.

Flame weeding typically uses a propane burner and is more than just burning off plant residue from last year. The point is to target the very small seedlings. The plants don’t have to be burned down to the ground. You only need to point the flame at about a 30-degree angle to the base of the seedlings. The heat ruptures the cells of the stem and the plant will wilt and die in a few hours.

Stale bed preparation combined with flame weeding can be quite effective. Stale bed preparation involves preparing your bed for planting, then waiting for a few days to allow weeds to germinate. Flame the weed seedlings then plant your crop with as little soil disturbance as possible. If you are direct seeding, as opposed to transplanting, you can flame the weed seedlings up until the crop emerges. Depending on soil moisture, it may be helpful to water the weeds up before flame weeding.

While flame weeding works well on most broadleaf plant seedlings, it is not very effective on larger plants, grasses or established perennials.

Because most weeds are very small, spring is a good time to use flame weeding. Research indicates the best time of day is afternoon.

When developing a weed control plan, consider all of the possible tools and start with those that are least damaging to the environment.

Other organic methods that are similar to flame weed are using steam or boiling water.

For more information, contact Ron Patterson, University of Idaho Extension horticulture/agriculture educator in Bonneville County, at 208-529-1390 or rpatterson@uidaho.edu.