Why Preemergent Herbicides Fail
A preemergent product stops weeds before they emerge and is one of the best tools for keeping invasive annual weeds out of lawns and flower beds. However, they are not always 100% effective. Recently I was involved in a focus group in helping to understand how to get preemergent products to work better. Here are some facts to know:
- . Products are transported to the soil where the weed seeds are, by rain, snow, or irrigation water.
- . As the weed seeds open to grow, contact with this barrier stops its growth. Power-raking or tilling can break up this barrier.
- . A long period of dry soil can allow weeds to grow without contacting the barrier. Too much water can move the products through the soil, so watering on a frequent basis during cool spring weather reduces the life of a preemergent.
- . Sunlight, heat, water, and soil microbes break these products down.
- . Eventually, products stop working.
What Moore Green does to ensure preemergent success
- . We want our treatments applied at the right time. If it’s too early, the products won’t be at the full efficacy when the weed seeds germinate.
- . As the soil temperature increases, we switch to a product that will control crabgrass even if it has germinated.
- . We don’t cut corners with our products. We want the best results possible.
- . Our Early and Late Spring Applications contain preemergent. By adding a second treatment, we extend the length of control to catch late summer weeds.