Pre-emergent should be applied to strengthen roots and prevent crabgrass before it starts.
During this time of the year your lawn is using up stored energy. This is also when broadleaf weeds are actively growing. Weed and feed should be applied to replenish your lawn meanwhile killing broadleaf weeds.
This is the hardest time of the year for your lawn. Problems such as heat, drought, foot traffic, and insects are all hurting your lawn at once. A summer guard fertilizer should be applied to strengthen your lawn through the heat.
Before the intense heat it is important to treat the lawn for grubs. The eggs will hatch into grubs, which feed heavily on grass roots throughout the late summer and early fall, causing extensive damage. It is also important to kill grubs to deter moles. The mole feeds mainly on grubs and can leave your lawn very damaged.
Should be done no later than mid-September. The best time to seed your lawn is in the fall. Cool nights, warm days, and ample rain fall make ideal growing conditions. There are many different kinds of seed to choose from. The most popular in the mid-west is Fescue and Kentucky Blue Grass. A mixture of these gives your yard the strength of the Fescue, and the thick, lush, green color of the Kentucky bluegrass. A starter fertilizer should also be applied with the seed to provide the seedlings with essential nutrients for a fast growth. Seeding your lawn can also be done in Spring. Beginning to Mid-April.
DO NOT PUT PRE-EMERGENT AND GRASS SEED DOWN AT THE SAME TIME!
Grass is recovering from a long hot summer and may be coming out of a drought-induced dormancy, so you'll want to give your lawn a shot of nitrogen to push blade growth.
A winter guard should be applied; this will prepare your lawn for freezing temperatures, strengthen roots and increase nitrogen storage for a healthier lawn next year.