Never try to seed a large new lawn by simply throwing the seed around with your hand. Use some type of equipment for spreading the seed. In all cases, follow the instructions that typically come with the various types of spreaders so that the seed is released in appropriate amounts. Whatever the type of equipment, sow in two steps to assure uniform distribution of the seed over the entire area.
Divide the total amount of seed in half. Sow the first half over the bare soil pushing the spreader in one direction, then sow the second half pushing the spreader at right angles to the first pattern. To sow the very small, light seeds of Kentucky bluegrass more easily, mix them with another material, or "carrier", such as sawdust, sand, or fine vermiculite.
Rake in Seed
For best germination, grass seed must be in good contact with the soil. If you seed over the dead stubble of existing turf, drag an upside down leaf rake over the entire lawn to dislodge any seeds stuck in the crowns of the dead grass plants.
If seeding on bare soil, lightly rake over the soil surface with a garden rake to bring the seed into contact with the top 1/8 inch of exposed soil. The seed does not need to be covered by soil, but, typically, only about 10% of the seed should remain visible after light raking.
Water, Water, Water
Regular, consistent watering is the key to success with grass seed. Seeds must always be moist. Try to water the entire seedbed twice a day unless it rains. A brief watering will keep the critical top ¼ inch of soil moist. In your absence a mechanical or computerized watering timer attached to your lawn watering device will assure a morning and late afternoon watering session. Some timers can be set for up to 7 days.
When the first new grass appears in 4 or 5 days, don't stop watering. These "nurse" grass seedling pop up quickly to protect the other seed varieties which take from 7 to 20 days to germinate. It also cheers up the yardener who is invariably encouraged to see such rapid results. Keep watering twice a day for at least 3 weeks if there is little rain to help. Once seedlings appear, do not abandon them. They will need regular, less frequent but increasingly deeper watering over the next few months.
Mulch Makes a Difference
While mulching a new seedbed is optional, new technology makes it so easy it’s worth doing. By reducing moisture loss through evaporation, mulching protects the seeds from drying out and enhances germination rates.
Until about 15 years ago yardeners typically spread a thin layer of straw or hay over newly seeded lawns. Now white polyspun floating row cover makes an ideal mulch for newly sown grass seed. Available in garden centers and hardware stores for a variety of landscape and garden uses, this fleece fabric allows air, light and water through so you can water right over it. Thrown over the seedbed and pegged into the soil, it not only maintains soil moisture, but it also fosters a warm micro-climate to speed germination. As the new grass grows it pushes up the fleece. Remove when it is time to mow. It can be reused many times.