Archived LHEI Article

CORN GLUTEN MEAL: AN ORGANIC HERBICIDE

SANDRA L. LAWSON, MASTER GARDENER

FOUNDING MEMBER OF THE LONGMEADOW HEALTH AND ENVIRONMENT INITIATIVE

September 9, 2003

The whole point of using integrated pest management [IPM] for your lawn and gardens is to control or maintain vegetation in a way that is safe, healthy, cost and time efficient and effective. The primary tenet of IPM is to prevent the pest in the first place!

Often, when home owners begin to think about changing their lawn and garden practices from chemical [AKA: human made, not organic or natural] applications of pesticides and fertilizers to organic methods, they ask, “What can I use to prevent weeds?”

Today, a non-selective pre-emergent herbicide and slow release organic fertilizer is available. Corn gluten meal [CGM] is produced from a wet milling process to make cornstarch. It will not harm beneficial insects, micro-organisms in the soil, pond or stream life, pets or children; it is available online, through mail order, and at local nurseries and home improvement stores. For additional professional and home gardener information, check the web site at www.bioscape.com/bioweed1.html.

The web site tells us that CGM is formulated to prevent the germination of broadleaf weeds and grasses [both annuals and perennials]. It is used in general agriculture, organic farms, commercial and residential landscapes, golf courses, greenhouses, parks and school grounds. It meets the requirements for the “Protect The Children Act”  under which schools, parks, and child care centers  must submit IPM plans to regulating agencies.

CGM can be used in vegetable, herb and crop gardens as it is totally organic. Use it with your bulbs, roses, and virtually any woody plant. It is composed of  98% corn gluten meal and 2% soybean oil. No mysterious inert ingredients, nothing unnatural, and you get a small fertilization boost to boast from the 10-0-0 formula. This 10% nitrogen provides a slow release fertilization.

Spread CGM by hand, broadcasting it over the bed to be protected and under established plants.  Because it inhibits seed germination and root development, apply after vegetable and flower seedlings have established their own root systems [when they have their “true” leaves]. It can be used until the day of harvest. You can also disperse the meal by a spreader for even distribution or till it into the soil. Then, moisten the beds and allow for a short drying time [2-3 days] before it becomes effective. During this dry period, the roots of new seeds trying to germinate die. Since CGM lasts but 5-6 weeks, it is essential that it be re-applied at 5-6 week intervals at the same rate of 20 lbs/1000 sq. ft.; CGM may need to be re-applied after excessive rains.

CGM prevents seeds from germinating but has no effect on established plants. You see a dandelion in your lawn? Crabgrass? Dig them! CGM will only help fertilize these plants if you do not remove them from the lawn. And for results: One research project demonstrated that CGM reduced crabgrass by 86% the first year and 98% the second. Dandelions were reduced by 100% in 4 years. Dig any weed that is there before it goes to seed and you’ll have the most impressive results cheaply and safely.