Corn Gluten Meal Used For Weed Control

The idea of using corn gluten meal for weed control burst on the scene in the early 1990's after Dr. Nick Christians at Iowa State accidentally discovered its herbicidal properties while he was testing it for suppression of turf diseases. After several years of efficacy studies and product development, corn gluten meal has gained national attention as being the first effective "organic" herbicide. Corn gluten meal is not a registered pesticide because the U.S. EPA has granted an exemption for corn gluten meal as an herbicide.

Corn gluten meal is a product of the wet milling process. It is a pre-emergent herbicide which inhibits root formation during germination. It is currently labeled for control of crabgrass, barnyardgrass, foxtails (Setaria spp.), dandelion, lambsquarters, pigweed, purslane and smartweed. Data suggest it has at least some activity on an even wider variety of plants. It is safe to use on established turf. Do not use corn gluten meal in an area in which you are trying to establish turfgrass.

Research shows 50-60 percent control can be achieved in the first year when applied at 20 lbs. per 1000 ft. Studies suggest that control is improved in successive years and as use rates increase. Currently it is sold as a dry product under various trade names, including Dynaweed, Safe ‘N Simple, Earth Friendly, W.O.W.!, Corn Gluten Meal Herbicide and Propac. It is sold for the homeowner market in retail stores as Concern-Weed Prevention Plus. Until recently it was only offered in powder form. Now a granular form is available which can be more easily applied with Vikon spreaders, rotary and drop spreaders. Application rates vary from 12 to 20 lbs. per 1000 feet, once in early to mid-spring and another in early to mid-August. Since the corn gluten meal is about 10 percent nitrogen, this catches two flushes of crabgrass and spreads out the nitrogen effect. Two applications at 12 lbs per1000 ft. Will provide nearly 2.5 lb. N per 1000 ft per year. The nitrogen is in a slow release form so there is little to no potential for foliar burn. Bulk orders cost about $950 per ton; 50 lb. bags run between $25 and $30. This is the same corn gluten meal sold at feed mills for animal feed; however, it is pelletized for easier and more uniform application.

Portions of at least two proteins in the corn gluten meal, called peptides, are the active ingredients in corn gluten meal. Laboratory studies show the peptides themselves to be significantly more effective at preventing weed germination than the corn gluten meal itself.

Source: John C. Stier, Turfgrass Extension Specialist, University of Illinois

Reprinted from The Green Line <http://www.urbanext.uiuc.edu/greenline/99v4/gl9904.03.html>

• If not needed for recreation, one of the best things to do is reduce lawn area - water runs over cut grass much faster than it does other vegetation. As an alternative, a grass and wildflower meadow is very attractive, low-maintenance, and will attract birds and butterflies. Trees and shrubs will provide other habitat and also shade the ground as well as circulate and cool the air.

• Clearly, many of us like a larger lawn. Maintain grass at a height of 3 to 4 inches and leave clippings on the lawn. Grass clippings provide a natural fertilizer that will save you money, reducing fertilizer run-off. It will also retain soil moisture, which will cut down on the amount of water that is needed.

• Have your soil tested for nutrients and pH (or you can get a do-it-yourself kit). If necessary, use dolomitic lime and slow release natural organic fertilizers.

• Plants need much less pest control than chemical companies would like us to think. If necessary, use environmentally safe products - many are available on the market today.

• If you have a lawn-care service, request that they use these and other environmentally sound techniques.

Reprinted from Sound Bites, Spring 2001

Home · Advocacy · Conservation · Biodiversity · Newsletter · Calendar · Education· Links
Email webmaster@menunkatuck.org
Last updated 18 September, 2004 .