It doesn’t matter whether you’re planting a new lawn or just replanting an old one; good site preparation is the key to success either way. You also should do a good job of site preparation whether you’re going to seed or sod. Both need that solid foundation.
The first step is to remove all construction trash, rocks, weeds, large roots, old tree stumps, and everything else that doesn’t belong in or under your lawn. If you need to grade the area, take off several inches of topsoil and pile it away from your work area; you’ll need it later.
Now slope the ground away from the foundation of the house. Don’t make a steep grade; the ground should drop about 6 inches for every 50 feet in distance from the house.
Try to avoid creating a steep slope or a hill if you can. However, if you do have a steep hill, a swale, or another area where soil erosion may occur, plan to plant sod, not seeds, in this area.
Once you have the site graded, return the topsoil to the area and rake it smooth. If there are any weeds growing in it, now is the time to apply herbicide to kill them.
If you’re planting seeds, the level of the soil should be even with or slightly below any hard surfaces such as sidewalks, driveways, etc. If you’re going to lay sod, the soil level should be 1 ½ to 2 ½ inches below those surfaces.
You should always take a soil sample before you to go the trouble of planting a lawn. Use a garden trowel to get 10 to 15 samples of the top six inches of soil. Use locations scattered evenly about the lawn area.
Mix the samples and let them air dry. When they’re dry, submit about 1 cup of the mixture to the state Extension Service soil testing program in your area. The results will tell you whether you need to add fertilizer, and how much. Follow the recommendations of the Extension Service, based on the results of your soil sample and the species and variety of grass you plan to plant.
If you want to save money and do this yourself, try something like a Digital 4 Way Soil and Light Tester for Plants and Lawn which tests for pH, moisture, temperature and light level.
If you’re going to put in an irrigation or sprinkler system, now’s the time. This is not entirely a do-it-yourself project; although you may be able to handle the installation, you need to get an expert to help you design it. A badly designed system won’t ever do what you want it to do, which is deliver the amount of water your grass needs, uniformly spread over your lawn, while conserving water at the same time.
This also is the time to apply any pre-plant soil amendments. You want your soil to be in the best shape possible in terms of organic matter, fertility, water-holding ability and drainage. All of these are affected by the amendments you add to the soil.
You may use organic or inorganic soil amendments. Organic soil amendments include compost, manure, and peat. Inorganic or mineral amendments include fertilizer, lime, sulfur and other chemicals that affect the fertility or pH of the soil.
Rely on the results of your soil sample tests to know exactly what to add in your situation. Every site and every lawn is different, and you need to know your own site conditions to add the correct amendments.
Till the Soil
Once you’ve added your soil amendments, run a tiller over the site. This loosens the soil and encourages grass to root quickly.
Grade Once Again
Just before you plant, grade the site one last time. You can hand rake, or use a drag such as a metal doormat. Follow that up with irrigation to “settle” the soil before you spread seed or lay sod.