Time Frame

• Cool-season grasses include bluegrass, fescue and rye grass and are best suited to growing conditions in Wisconsin. You can plant cool-season grasses in either spring or fall, but early fall is generally considered to be the superior time. The University of Wisconsin website recommends planting grass between Aug. 15 and Sept. 20.
  
  

Conditions

• Fall is considered the best time to plant grass in the Midwest for a variety of reasons. If you plant in spring, grass growth will coincide with the germination of perennial weeds, which will compete with your grass for moisture and nutrients. Also, nights in Wisconsin get longer and cooler in fall, which helps keep new grass moist.
  
  

Considerations

• What kind of grass you plant is just as important as timing in Wisconsin. In sunny areas, spread a seed mixture that is about 65 percent Kentucky bluegrass, 20 percent fine fescue and 15 percent perennial rye grass. For shady spots, look for a mixture that is 40 percent Kentucky bluegrass, 50 percent fine fescue and 15 percent perennial rye grass.