Lime doesn't just raise the pH of soil. It also supplies important nutrients like calcium and magnesium, reduces the soil's toxicity, and makes soil nutrients more available to the grass. All of these benefits make lime a great nutrient source for germinating grass seed. When seeding a new lawn, many homeowners choose lime pellets over powdered lime because they can easily be spread over the ground and are less likely to drift to areas where lime is not needed. But before you put lime pellets onto your lawn, first have the soil tested to determine exactly how much lime is needed.
Test your soil's pH or have it tested by your local county extension office. The report that you receive will dictate the amount of lime that you need to add to your lawn based on your soil type (light, sandy soils require less lime to raise their pH and heavier soils require more lime to raise their pH). Most types of grass grow best when the soil's pH lies between 6.2 and 6.5. A soil test performed by a county extension office will also inform you of any nutrients that need to be worked into the tilled soil before you plant your grass seed.
Calculate the amount of grass seed that you will need. Different types of grass have significantly different application rates. The back of your grass seed's package will list the grass seeds' optimal application rate per 1,000 square feet. Use that figure to determine how much grass seed you will need for your lawn. Measure that amount into a container and set it aside.
Follow the lime manufacturer's instructions and your county extension office's report to determine how much lime to spread over the lawn. When consulting your county extension office's report, keep in mind that pelletized lime should be applied at a higher rate than powdered lime. For most lawns you will need between 15 and 30 lbs. of pelletized lime per 1,000 square feet.
Put half of the lime you will need for your lawn into a broadcast spreader. Calibrate the spreader to accommodate the size of the lime pellets and set the application rate to half the application rate needed. Go over your lawn once with your spreader to broadcast half of the lime at half the rate. Then fill the spreader again (at a 90 degree angle to the direction you first went in) and broadcast the second half of the lime.
Repeat step 4. But this time, fill the spreader with grass seed instead of lime pellets.
Go over the freshly planted area with a lawn roller to ensure that the seed has good soil contact.
Water the planting area with 1 to 2 inches of water.