One of the most important breakthroughs in organic lawn care has its roots in a fortunate accident by Iowa State University researcher Nick Christians. The natural herbicide that resulted from Christians' research (made from corn gluten meal) is now patented, and is licensed to 15 distributors for use in turf and home gardens.
Christians discovered corn gluten meal's herbicidal activities more than a decade ago while using leftover cornmeal to grow a pathogen found on golf course turf. While the experiment was a "failure" for its original intent, Christians found that the protein part of the corn--corn gluten meal (CGM), a corn milling byproduct--could inhibit root growth. He also discovered that the corn gluten meal contains 10% nitrogen by weight, thus making it an ideal "weed and feed" product.
CGM is labeled for use on turf, field crops, and home gardens. Among the weeds controlled with pre-emergent application of the product are crabgrass, dandelions, smart weed, redroot pigweed, purslane, lambsquarters, foxtail, and barnyard grass. Both powder and pelleted formulations are available--Christians says research shows that both forms are comparable in effectiveness.
Christians is now looking at the effect of corn gluten meal on garden seeds. While the research is still in the early phase, initial indications are that deep-seeded species such as beans and peas as well as radishes fare very well with CGM. However, shallow-seeded species such as carrots and lettuce seem to incur damage. Most labels call for the herbicide to be applied pre-emerge in spring and fall. Is CGM suitable for your garden? Christians says the best approach is to first try the product on a small area of your yard or garden.
In turf situations, the CGM is often applied at 20 lb/1000 square feet; in garden situations, the rate may vary from 20 to 60 lb/1000 square feet. Garden seed can be sown slightly deeper than usual and CGM broadcast uniformly over the area and lightly raked into the surface, then watered in well. The CGM then inhibits growth of the weed seedlings' root tips.
Potential problems with CGM stem from the fact that extensive moisture and microbial soil activity can reduce its effectiveness. The other drawback is the higher cost of CGM as compared with other weed and feed products. For instance, one catalog offers a bag of CGM treating 5,000 square feet of lawn for $43; a conventional weed and feed product with a 27-3-6 analysis costs $15.00 to treat the same area. However, many consumers seem willing to pay the higher price because of its nontoxic nature.
Currently there are seven, and soon to be eight companies marketing the natural herbicide to Iowans under a variety of trade names. Christians says that a newly issued licensee, Necessary Organic, will make CGM available in two Iowa merchandise chains within the next year. Here are the companies selling CGM.
|Company||Phone Number||Product Name|
|Blue Seal Feeds||603-437-3400||Safe 'N Simple|
|Cereal Byproducts, Inc.||847-818-1550||Earth Friendly|
|Down to Earth Distributors||541-485-5932||Supressa|
|Grain Processing Co.||319-264-4211||Corn Gluten Meal|
|Greener Pastures||612-331-2904||Tiger by the Tail|
|Hardesty Organic Supply||415-325-5959||Supressa|
|Manning Agricultural Center, Inc.||800-248-4409||ProPac|
|Rhode's Services, Inc.||972-864-1934||GreenSense|
|Safe Earth Lawn & Gardens||515-222-1997||Corn Gluten Meal Weed Control|
|Soil Technologies Corp.||515-472-3963||DynaWeed|
|Walt's Organic Fertilizer Co.||206-297-9092||Organic Weed-Stopper Plus|
|Winton Graf||612-887-0068||SUPER ORGANIC "G"|
Further information about CGM can be found on the Corn Gluten Research page.
This article originally appeared in the June 20, 1997 issue, pp. 98-99.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on June 20, 1997. The information contained within may not be the most current and accurate depending on when it is accessed.