Q: Is there any difference between the pre-emergence for winter weeds and the pre-emergence for summer weeds?
A: No. While different chemicals are used in different products, they all prevent seed germination or sprout/root elongation after seedlings emerge. We’re getting close to the optimum time (Sept. 15) for fall application of pre-emergent chemicals to lawns. I’ve already seen chickweed sprouts in a shady flower bed.