Herbicides are chemical treatments designed to kill or inhibit the growth of certain plants. They are usually targeted at weeds, and they can make a gardener's life much easier. The decision to use herbicides should only be made after the benefits and the problems have both been considered. Some herbicides have the potential to damage the environment.
Herbicides are placed in two categories. The first category is selective herbicides. They are referred to as selective because they kill only certain types of greenery. These would be the herbicides you might spread on a lawn to kill the weeds but leave the grass intact. The second category is nonselective herbicides. As their name implies, these chemicals will indiscriminately kill whatever plant they come into contact with in significant quantities. This is the type of herbicide you must used extra caution with as one miss-spray could kill a beautiful plant you have been cultivating for years.
Pre-emergent herbicides penetrate the soil and kill weeds before they germinate, whereas post-emergent herbicides kill weeds that have already germinated and established themselves. Post-emergent herbicides may be either selective or nonselective. Horticulture specialist Tom Fowler states that the post-emergent nonselective variety is to be used primarily for spot treatments.
Identify the type of weed that has cropped up before you apply a weed killer. Different products have different chemical compositions that target specific weeds. All herbicides do not work interchangeably. Follow manufacturers' instructions as to what time of year and what weather conditions are most conducive to herbicide application. Application during high winds may result in damage to nearby plants and grasses.
One problem with herbicide use is the potential of a number of these chemicals remaining in the soil for an extended period of time. Variables influencing herbicide persistence in soil include soil composition, herbicide composition and weather conditions. When herbicides remain in the soil past one growing season, they have the potential of negatively affecting the following years' crops.
The drifting of herbicides from the intended application site to surrounding areas can be caused by a number of factors including weather, method of application and the chemical composition of the herbicide. Herbicide drift is a serious environmental problem that has become a legal problem for some. According to D.L. Uchtmann, Professor of Agriculture at the University of Illinois, legislation is in place to protect the environment from herbicide drift and hold those responsible accountable for any damages. Irresponsible use of herbicides may result in a lawsuit.