Greener Weed 'N Feed
The list of truly natural herbicides is small. While many species of plants can inhibit the growth of other plants — see what grows under a pine tree if you let the needles go uncollected—the transition is huge from that simple statement to finding natural substances which kill off weeds but doesn’t harm grass. Some weed-killing compounds have been extracted from the black-walnut tree, but you probably don’t have the resources to get a stand of black walnut up and thriving in your backyard — not this summer, anyway. Sunflowers have similar properties, but again, they’re not right for the lawn.
The one natural weed killer that works, and that you need to ask your lawn-care professional about right away, is corn gluten.
Gluten Morgen
Corn gluten is a byproduct of the milling process that turns corn into everything from Sugar Pops to ethanol. It’s high in protein, and likewise high in nitrogen, so for many years it had been fed to hogs as a dietary supplement. Corn gluten’s high nitrogen content spurred interest in its agricultural applications, and in 1991 an Iowa State university researcher named Nick Christians
secured a patent for corn gluten as a lawn food.
Corn gluten works by inhibiting the root formation of germinating plants, and by drying out and cracking weed seeds, keeping them from germinating. It works especially well on crabgrass, dandelions, smart weed, redroot pigweed, purslane, foxtail, lambsquarters, and barnyard grass.
Because it doesn’t work on mature weeds, corn gluten needs to be applied early in the weed-growing cycle. Since weeds grow on several cycles in a year, that does not mean corn gluten has to be applied right away in the spring. A late spring or early summer initial application will work fine, with “booster shots” every four to six weeks. The more times in a year you apply corn gluten, the better it works. Ask your lawn-care professional for recommendations.
Dry, Granulated Or Pellet
Corn gluten comes in three basic types. A lawn-care professional can easily work with any of these types, but be sure to ask which type is being applied to your lawn.
Unprocessed corn gluten looks like fine cornmeal powdery in texture. It can't work its way down through grass or mulch, which makes it a good choice for newly seeded lawns. The added boost of nitrogen it provides can also help jumpstart new lawns.
Granulated corn gluten can be spread using traditional spreaders or mixed into a paste and applied to problem areas. Pelletized gluten is the easiest to spread and is best for spring and fall applications.
Any corn-gluten-based pesticide only works after it’s been wetted down, so be sure you or your lawn-care professional runs the sprinklers after an application of corn gluten.
Whichever type of corn gluten you choose, rest assured that you’re doing something good for your grass that’s only bad for one thing: weeds.
Straight-Shootin’ Gluten
The most important things to know (or to ask your lawn-care professional) about corn gluten:
? When used properly, corn gluten will control the following weeds: crabgrass, dandelions, smart weed, redroot pigweed, purslane, lambsquarters, foxtail, and barnyard grass.
? Corn-gluten-based products cost about 10 percent more than traditional chemical weed-‘n’-feeds.
? Coverage depends on the form of corn gluten used. Generally, corn gluten is applied at 20-40 pounds for every 1,000 square feet of lawn.
? Corn gluten needs water to work, so wet it down by running the sprinklers for 10 minutes or so after applying.
? One application works for four to six weeks. Monthly application may be necessary if your soil is heavy soils or the weather is unusually rainy or hot.
? Results improve with repeated use over time.
