Apply 1 to 1.5 pounds of nitrogen per 1,000 square feet, preferably quick-release nitrogen (the most common type sold in garden centers). The settings recommended on lawn fertilizer bags usually result in about 1 pound of nitrogen per 1,000 square feet, Ward Upham of K-State says.
The second most important fertilization of cool-season grasses is in November fertilizer, to help the grass green up earlier next spring and provide the nutrients needed until summer. It also should be quick-release applied at the rate of 1 pound actual nitrogen per 1,000 square feet, Upham says. (Spring fertilization often causes grass to grow too fast, Patton points out; it’s best to wait until around early May before putting on any fertilizer next year.)
• Good seed/soil contact: Seed lying on top of the ground rarely germinates and grows. A leaf rake can be used to lightly mix the seed into the soil if you’re not using a core aerator or slit seeder or verticutter. Some seed will still be visible after mixing.
• Fertilization: Use soil test recommendations or a starter fertilizer at the rate suggested on the bag. The fertilizer should be applied before tilling if you are tilling or after slit seeding or core aerating.
Core aeration requires the least amount of water, because germination occurs in aeration holes that stay moister than a traditional seedbed. The holes also give new-lawn fertilizer a place to go. If you use a core aerator, go over the area at least three times in different directions with the aerator, then broadcast the seed.
Other machines that can be used for seeding are slit seeders and verticutters.
• Watering: Keep the soil moist but not waterlogged. During a hot spell, that may mean a light watering three times a day. As weather cools, cut down to once a day. After grass starts growing, gradually back off on watering.
• Mowing: Mow when the seedlings reach 3 to 4 inches tall.