When should pre-emergence be applied to a fescue lawn and how long between...
Now is the time to start applying pre-ememergent herbicides in Oklahoma. February to early March is ideal.
Each pre-emergent herbicide is different in the amount of time the label recommends before you seed. Many recommend 60 days. Research from the Univ of Nebraska and Kansas State have shown that Tall Fescue seed can germinate through this pre-emergent. It is not going to be 100% effective. But you can get 50-70% germination. My recommendation is don't apply pre-emergent if you have to seed. Seed now and then wait until the grass is about 3-4 weeks old and then apply the pre-emergent.