I want to garden this spring without using chemicals. Are there any safe, non-toxic garden herbicides?
—D. Muller, Jackson, MS
There are now several natural herbicides on the market. One of the most effective natural ingredients is corn gluten meal, a yellow powder that is a waste product of the corn milling process. While the meal has been used in dog, fish and other animal foods for years, it has only recently been marketed as a natural herbicide. As researchers at Iowa State University’s (ISU) Horticulture Department discovered, the material naturally inhibits the growth of seeds” initial root systems, while doing no harm to already established plants.
ISU researchers say that once vegetables or flowers have their first true leaves, corn gluten meal can be safely and effectively applied to kill weeds. ISU scientists also note that, because corn gluten meal is high in nitrogen, it is beneficial to surrounding plants, doubling as a fertilizer.
It has been reported that corn gluten meal is particularly effective against dandelions, pigweed, crabgrass, plantain and curly dock. ISU scientists suggest an application rate of 20 pounds per 1,000 square feet and they say the product remains effective for five to six weeks. Researchers say that corn gluten meal should be applied to lawns about three to five weeks before weeds begin to grow.
The U.S. Environmental Protection Agency’s (EPA) Office of Pesticide Programs urges people to decrease the amount of chemical herbicides used to battle weeds. There are already more than 865 active ingredients registered for use in pesticides, herbicides and fungicides. About 350 pesticide products, including herbicides, are used on the foods we eat and to ward off pests from our homes and pets. But pesticides and herbicides often contain toxic substances that are harmful to human and ecological health.
ChemFree+ is one brand of herbicide that uses corn gluten meal. Available from Chem Free Lawns, it is advertised as both a natural weed control and fertilizer for lawns and gardens, harmless to people, pets, groundwater, insects and soil microorganisms. Comparable products include Dynaweed, from the American Natural Products Company, and “A-Maize-N,” from Planet Natural.
CONTACT: Chem Free Lawns, (952) 473-2127, www.chemfreelawns.com; American Natural Products Company, (800) 221-7645; www.americanatural.com; Planet Natural, (800) 289-6656; www.planetnatural.com; Iowa State University’s Horticulture Department, (515) 294-2751, www.hort.iastate.edu; U.S. Environmental Protection Agency, Office of Pesticide Programs, (703) 305-5440, www.epa.gov/pesticides.