The cutoff for planting cool-season grass is 6 weeks before the average first fall frost.
The Family Handyman on MSN

What To Know About Turf Grass

What's the common denominator in nearly every yard? Turf grass. Find out what's so special about this ubiquitous landscape ...
The best time to aerate is when your grass is actively growing—spring or fall in cool areas, and late spring in warm ones.
The growth of lawn grasses slow in the fall before they enter winter dormancy. Learn when and how to cut different types of lawn grasses before the first frost to keep them healthy during the winter.