Weeds and other invasive plants can take over gardens and landscaped areas, as well as choking out native plant life in natural areas. Herbicides kill these unwanted plants, though some herbicides may also destroy the desirable plants if you're not careful. Choosing the proper application method ensures the herbicide only targets the unwanted plants in the way most likely to kill them.
Broadcast spraying provides wide, even coverage of affected areas. This method works best for killing large numbers of weeds in an area before the desirable plants are transplanted, such as when clearing an area for a new garden bed. Broadcast sprayers come equipped with a variety of nozzle shapes that allow you to cover either a wide or narrow band of vegetation, depending on your needs.
Banding, a soil treatment, conserves herbicide while still ridding the area of unwanted plants. It is used with row crops or to kill woody plants over a large area. Herbicide bands are either applied down the center of crop rows or applied every 4 to 6 feet over a large area. Irrigation or rainfall forces the herbicide into the root zone, where it kills the plant.
Foliar treatments target small trees and shrubs. Sprayed onto the foliage of the plants, the herbicide is absorbed through the leaves and leads to plant death. These treatments work best during the spring and fall and are least effective during hot, dry weather. Drifting of the herbicide during spraying is a concern, though drift control additives are available that prevent the spray from affecting nearby desired plants.
Broadcast methods apply to granular herbicides, using either gravity flow or centrifugal spreaders. The granular herbicide is either broadcast over a large area or applied in narrow bands between crop rows or every 4 to 6 feet, much the same as liquid herbicide application.