What is required for preemergence herbicides after application?

For preemergence herbicides to be effective, they typically require rainfall or irrigation shortly after application. This moisture helps activate the herbicide in the soil, allowing it to form a barrier that prevents the germination of weeds. When rainfall occurs within a week of applying preemergence herbicides, it ensures that the active ingredients are integrated into the soil, increasing efficiency in weed control.

High temperatures, while they can influence the activity of herbicides, are not specifically required for the initial effectiveness of preemergence products. The application of fertilizer is unrelated to the activation of herbicides, as it does not enhance their effectiveness against weeds. Windy conditions can be detrimental, as they may lead to uneven application and drift, which can jeopardize control over targeted weed species.