Organic gardeners often struggle to control annual weeds in their gardens. While there are many organic products on the market touted as helpful in controlling weeds, there has been little research testing them against each other.
Researchers at the Organic Farming Research Foundation and Purdue University tested four different organic weed control sprays, plus flaming with a hand-held flamer, on seedbeds to be planted in greens. Weeding greens and lettuce beds can be very time consuming, especially for organic growers, so finding an effective alternative to reduce weeds will save growers time and money. Researchers tested Burnout II (contains acetic acid), Matran 5 (contains clove and other essential oils), 10% vinegar solution, 13% vinegar solution, and an LP gas hand-held flamer. They were particularly focused on controlling chickweed, purslane, galinsoga, and grasses. Seedbeds were tilled and allowed to sit for 2 weeks so the weeds could germinate. Three applications of each treatment were made on the 3' by 5' test beds in May, June, and August.
It turns out organic sprays weren't the best solution. Although Burnout II reduced the weeding time the most overall, the hand-held flamer was more convenient to use and more effective in controlling tougher weeds, such as grasses and purslane. Matran 5 was the next most effective weed killer. All treatments worked best if the weeds were treated when less than 4 inches tall.
For more information on this research, go to: Organic Farming Research Foundation.