Lawn seeding is not just for patchy or thin grass, but is a great way to choke out crabgrass and other weeds. Reseeding an entire lawn is easiest to finish in the fall when these weeds go into dormancy and the grass seed will have a chance to germinate before it also becomes dormant. A spring seeding is usually just for treating small areas that lack any new grass sprouts.
What to Know Before You Shop
Before shopping, evaluate the lawn space including the amount of sun exposure, water runoff or puddle potential, and amount of clay in the soil. Each of these variables will impact the type of grass seed that will be most beneficial for the lawn. Next, estimate the size of the lawn in square feet. Most lawn supplies are measured out in square feet for thin layers, or cubic feet for layers with at least an inch of depth such as sand or peat moss.
Till the Soil
Prepare the lawn area first by removing all remaining portions of the previous lawn or landscaping. Use a pointed shovel for small areas and clumps or rent a sod cutter to remove all of the old grass and weeds. Also remove any rocks that are too large to pass through the tines of a rake. The exposed earth will need a good tilling to loosen it up before the newly planted seed can take root. Remove any rocks brought to the surface throughout the tilling process.
While tilling, add in sand and compost in alternating one-inch layers to achieve the desired texture. Continue tilling the soil by making several passes across the lawn in multiple directions until there are no clumps or patches of packed soil.
Test the pH Balance
Next, test the soil's pH balance. Grass seed requires a pH level about 6.0-7.5 for good sprouting. If the soil tests below a 6, indicating it is highly acidic, add lime in to neutralize it. Alternatively, if it is above a 7.5 or alkaline, add sulfur to bring it into a healthier range for grass seed. Incorporating fertilizer at the same time will give the seeds a nutritional jump start.
Sprinkle in all three supplements to the soil one at a time using a broadcast spreader to reach all areas of the lawn. Then work them into the soil using a metal rake.
Distribute the Seed
Throwing out the grass seed is usually the most fun of the whole project. Simply toss it out, trying to keep it evenly distributed. Four pounds of grass seed is enough for about 1,000 square feet of lawn.
Adding extra seed will not increase the thickness of the final lawn. To a certain extent the grass seedlings will shrink or expand according to the available space, so any excess is a wasted effort.
Gently rake the grass seed into the earth without redistributing it. Then lightly water immediately after seeding, but only water enough to dampen the soil without creating puddles.
Until seedlings form, water the area two to three times a day for about five minutes. Then water once a day for about 15-30 minutes.