When corn is in the rapid growth stage (V8 (8 leaf) to V11 (11 leaf)), it has the ability to grow 30 inches a week, if environmental conditions are right!
An issue that can often surface with rapid crop growth is timing post-emergence herbicide applications. The window of opportunity for treatment with most post-emergence, or over the top, applied products closes very quickly. In addition to rapid growth, weather events, such as high wind or rainfall, can interrupt your plan and complicate how you time these herbicide applications.
All herbicide products provide information on the limits of an application on the product’s label. In corn and soybeans, these limits can be by growth stage, height of crop or days before harvest interval required. Chemical companies have researched timing of their products and identified the most efficient rates to achieve the desired weed control while avoiding crop injury and herbicide residue troubles. Remember to always follow label use directions. It is the law.