Weeds take up resources needed by your garden plants, slowing crop growth and the size of your harvest. They can also harbor diseases and provide a home to insect pests. It can be difficult to keep the weeds in your garden under control due to the large number of seeds they produce and their fast growth. An integrated weed management program including chemical herbicides can keep these leafy pests from taking over your garden.
Cultural Weed Control
Part of your weed-killing system should be cultural control, such as tilling and hoeing. Help reduce the number of weeds that spring up next year by tilling them under or mowing them in the fall before the seeds mature. Cultivating or tilling your garden after weeds have sprouted in the spring will kill young weeds and push seeds deeper into the soil, reducing their chance of germinating.
Herbicide containing DCPA is a pre-emergence grass controller labeled for several vegetable and fruit crops. Pre-emergence herbicides prevent seeds from germinating, and will not work on grass that has already germinated. Apply this herbicide to weed-free soil, then water thoroughly to help the chemical work its way into the ground. Read the label carefully to avoid harming your garden crops. Do not apply DCPA herbicides within 6 inches of vine crop stems such as tomatoes or cucumbers.
Herbicides containing trufluralin are also pre-emergence herbicides, and must be applied to the soil before planting the garden. Trufluralin comes in a water-soluble form mixed at a rate of two to three level teaspoons per gallon of water per 1,000 square feet, or a granular form which is sprinkled evenly. After application, mix the chemical with the top two to three inches of soil with a tiller or hand rake. Plant your garden within two to four weeks of application.
Corn Gluten Meal
Corn gluten meal is a by-product of commercial corn milling and contains the protein portion of the corn. It works as a pre-emergence herbicide and, unlike synthetic herbicides, poses no health risks to humans or animals. Corn gluten meal is effective only against seeds and will not eliminate weeds or grasses that have already germinated. Perennial weeds such as dandelions (whose roots survive winter) won't be killed, but they will not be able to multiply because the seeds they produce will not sprout in corn gluten meal-treated soil. Because it acts on seeds, wait until your garden plants have sprouted and are established before applying this product to your garden.
Chemical herbicides can be dangerous, and you may want to consider other means of weed control if you have children or pets who have easy access to your garden area. Herbicides applied to the garden can leach into other areas, such as backyard ponds, and cause unforeseen problems. Always use caution and follow label directions when using these products on your garden.