15 Feb Pre-Emergents, Your 1st Line of Defense
Weed control begins with a proper turf grass management program. Practices which encourage a dense and healthy lawn will most certainly include fall and spring pre-emergent applications to your turf. Pre-Emergents are designed to control germinating weed seeds and not existing weeds. Even just a few weeds left to their own devises can quickly become a problem. They rob the turf of water, sunlight, and nutrients. By adding a pre-emergent to your turf plan in the fall and again in the spring, gives you the upper hand in winning the war for a beautiful, uniform looking lawn. These applications work best when applied at a time when night-time temperatures reach 55-60 degrees for 4 consecutive days.
The way a pre-emergent works is the product lays under the turf to permanently eliminate weeds, when the seed is allowed to germinate the young sprout is killed. A Pre-Emergent is activated in the top layer of soil, where the weed seeds sprout, and by design it stops the plant from ever growing. This is one key advantage over just putting down new soil or mulch to bury the seeds. Weed seeds remain viable many years, waiting for a chance to pop up. Pre-Emergents break the cycle of constant regrowth of new weeds.
The chemical is activated by applying water, usually within a couple of days, sufficient to soak it into the ground. Waiting too long to water in the product exposes the chemical to light and it will lose potency. You need not worry about over watering the product.
It can remain effective in the soil for several weeks up to several months. A post-emergent is the best defense for existing weeds and can be used during the growing season.