Early to mid-August marks the beginning of the best time of year to seed lawns. Northern parts of the state should plan to complete seeding by early September. In southern Minnesota, seeding can continue until about the middle of September. This allows time for new seeds to germinate and become established before cold weather arrives. You don’t have to be seeding a new lawn to take advantage of this prime seeding period. This is also a great time to repair your existing lawn. Lawn worn thin by summer activities can be reseeded with a mixture of mostly Kentucky bluegrass and perennial ryegrass. Average home lawns that need a little thickening up can be seeded with a mixture of 60 percent Kentucky bluegrass, 30 percent fine fescue and about 10 percent perennial ryegrass. It can be difficult to establish a lawn in shady areas. Of our lawn grasses, the fine fescues have the best shade tolerance, but even they will decline in densely shaded conditions. In such situations, it is best to establish other types of perennial ground covers rather than struggling with grasses. Pruning trees may also help grasses by allowing more sunlight to reach the ground. Most fine fescues will survive in areas receiving an hour or two of direct sunlight. Avoid keeping shaded areas too wet as fine fescues are better adapted to dry, shady conditions. If the area has more filtered shade and is somewhat on the moist side, you can try a type of bluegrass known as roughstalk bluegrass (Poa trivialis). It is often included in shady lawn mixes commonly available at garden centers. This species is a lighter green and finer-textured than common Kentucky bluegrass, but is the only species with much shade tolerance. Once you have decided which grasses to plant, it is important to use the right amount of seed for the job. Most of our lawn grasses can be seeded at three to five pounds per 1,000 square feet. If the seed mix is primarily Kentucky bluegrass, seeding at lower rates is better. If seed mix is primarily fine fescue, higher rates are better. Avoid putting down extremely high rates of seed. This creates so much competition between plants that it actually slows establishment of the lawn. For more information about the seeding process, visit the “Sustainable Urban Landscape Information Series” Web site at www.sustland.umn.edu. Bob Mugaas is an educator specializing in horticulture with the U of M Extension Service.
