Spring is the perfect time to reseed those shady areas of your lawn. Although fall is the preferred time for overall reseeding, over-seeding your existing lawn in the spring is a good alternative.
Step 1: Avoid pre-emergent. Crabgrass preventer is a pre-emergent. It will stop any new seed from germinating. Choosing to seed in the spring means forgoing chemical crabgrass warfare. If you have already applied a pre-emergent then planting new seed is not an option for you until fall.
Step 2: Rake your yard and clear away any debris that has accumulated over the winter. Trim back tree branches to optimize the sun’s access to your lawn. Renting a de-thatcher or power rake from your local hardware store or rental outlet is a good idea at this point. A de-thatcher will lift up accumulated grass clippings from years past and leave the soil exposed for the new seed. It will also create a pile of thatch that you will need to rake up before proceeding.
Step 3: Loosen the soil. If you didn’t aerate your lawn in the fall, now is the time to rent a core aerator. The core aerator will pull up plugs of soil and redeposit them on top of your lawn. This allows water to reach the roots of existing grass while simultaneously providing a loose layer of good soil for your new seed to germinate in.
Step 4: Sow your seed. Fescue-type grass seed requires soil on three sides to germinate. If you chose to hand sow or mechanically spread your grass seed you will need to go back and rake it in to ensure proper germination. An alternative to hand sowing is to plant your seed using an over-seeder or verticutter. These machines lightly score the surface of your lawn while dropping the seed, thus planting the seed rather than simply sowing it.
Step 5: Water. Water. Water. Grass seed needs three things to germinate — soil, water and sun. Without all three, your efforts will be moot. After planting your seed, keep the top 1/4-inch of your soil moist, but not wet, for two to three weeks. Watering a little each morning is the best alternative. Once outdoor temperatures reach above 50 degrees for 10 to 14 consecutive days, little sprouts of grass should start appearing. Continue to water the lawn frequently and wait for the seedlings to mature before mowing. Mower blades tend to uproot new grass rather than cut it.