Herbicides for Plants

An herbicide is a type of pesticide which targets weeds. It works by killing the plants directly or by interfering with biological mechanisms within the weed. The presence of weeds indicates that an opportunity exists for their establishment. Your desired plants may be stressed from disease or from environmental causes. Bare ground may provide habitat for weeds to become established. Because of their toxicity, herbicides require proper handling to avoid harmful environmental effects.

Pre-Emergent Herbicides

Pre-emergent herbicides attack weeds before they emerge from the ground. Their purpose is to prevent seed germination. This action gives the desired plants in your garden or lawn time to become established. You can apply these herbicides with a sprayer or spreader. The timing depends upon the weed in which you are targeting. You typically can apply these in the spring for lawn weeds such as crabgrass. You can also use them in the fall to help prevent spring emergence of these weeds.

Post-Emergent Herbicides

Post-emergent herbicides act on weeds after they have germinated. You will apply these products directly onto the weeds, taking care to avoid non-targeted plants. You can use post-emergent herbicides to take care of any weeds not controlled through use of pre-emergent herbicides. These pesticides work best if applied when the weeds are actively growing, but before they have gone to seed. For more persistent weeds such as thistle, you may need to apply these herbicides more than once for adequate control.

Biopesticides

Biopesticides use natural ingredients as their base, explains the U.S. Environmental Protection Agency (EPA). Generally, these products are safer to use and less toxic than other types of herbicides. Sources include bacteria, minerals and animals. According to Environmental Pest & Lawn Services, Inc., you can use household products such as baking soda for an effective herbicide for crabgrass in small areas. A benefit of using biopesticides is that these products are selective herbicides. A selective herbicide targets a specific type of plant. This quality reduces the risk of damaging other plants.

Organic Herbicides

While all pesticides have the potential to be hazardous for the environment, organic herbicides offer a safer alternative to conventional herbicides. Vinegar is a common, organic herbicide which you can apply directly onto weeds. A10 percent solution can kill many weeds. Higher concentrations may be necessary for more tenacious weeds, advises the U.S. Department of Agriculture. Other examples of organic herbicides include corn gluten meal and several commercial blends, according to the Lawn Care Academy.