If you have not applied fertilizer or pre-emergent herbicide to the lawn, you need to get moving. The synthetic pre-emergents are Dimension for the grasses and Gallery for the broad leaf. The all-natural is corn gluten meal. Remember to follow the label directions.
For those of you that are over-seeding rye grass, do not apply pre-emergent. Over seeding a lawn with cool season grasses provide color and increase wear and weed tolerance during winter months. You also stay in better shape because you have to mow the lawn. But during early spring when Bermuda and St. Augustine are beginning to green-up, cool season grasses are at their peak growth period. They will compete with the lawn grass during spring and delay recovery.
Two basic types of rye are annual and perennial. The application rate of rye grass seed should be at a 5# – 10# per 1000sq ft. I would recommend perennial over the annual. Yes the annual is cheaper but the perennial makes a much better lawn. And since you will have to mow, pick the best one.
Never over seed with fescue grass. This is a major league mistake. Fescue is a permanent grass and it fights for survival much harder than the ryes. It will severely delay Bermuda and, depending on conditions, stop St Augustines’s recovery from the winter dormancy.