Read the herbicide label and adjust rates, if needed, based on soil type. Applying certain herbicides to soils having less than 0.5 percent organic matter is apt to damage plants. Most chemicals will not damage plants in soils with 2 percent or more organic matter. Some herbicides give poor results when used on soils with organic matter over 4 percent. Under these conditions, select herbicides that are systemic or that are absorbed through foliage.
Most residual herbicides work best when incorporated into the soil by rainfall or irrigation.
They will have maximum effect if the water is applied within 4 to 10 days after application. Failure to water adequately can diminish the herbicide's effectiveness. Generally, 0.5 inch of water is sufficient. Tank mixing of herbicides Concentrated herbicides should never be added directly to an empty tank. Add one-half of the necessary water to the tank, then the herbicide concentrate, and finally the rest of the water.