The best way to have a great lawn is to have a healthy lawn; it crowds out weeds and is strong enough to resist disease. Give new lawns a good start with a soil test at the local university agricultural extension and a gift of organic matter to deeply cultivated topsoil. Some turf grasses ask no more, but some varieties and some soils require a boost with starter fertilizer.
Starter fertilizer is a special blend of nitrogen, phosphorus and potassium (N-P-K) that is formulated to aid germination and seedling growth without "overdosing" the young turf on nitrogen, which is the elementary nutrient needed for plant tissue growth. Starter fertilizer typically contains phosphorus and potassium and low levels of slow-release nitrogen. Seasonal fertilizer, on the other hand, tends to contain more nitrogen or an equal blend of the three major nutrients.
The best planting time for seeding new lawns coincides with the time that the grass would normally re-seed itself; North Carolina State University (NCS) recommends seeding warm season grasses in spring and cool season grasses in fall. The exact time to seed depends on local climate conditions; seeds need a soil temperature of about 60 degrees Fahrenheit for optimum germination. Starter fertilizer must be either incorporated into the soil before planting or applied at planting time.
Most fertilizer manufacturers produce fertilizers formulated for new lawns. The "P" number in the N-P-K percentage label should be larger than the others. Chemical orthophosphates and polyphosphates begin with rock phosphate being heated or washed into phosphoric acid. Organic phosphorus fertilizer is based on manure or water treatment sludge.
Iowa State University recommends cultivating in 0-20-0 superphosphate or 0-46-0 triple superphosphate 4 to 6 inches deep into topsoil that has not been tested. The University of California's Guide to Healthy Lawns recommends incorporating a starter fertilizer into the top 2 to 4 inches of soil with an N-P-K rating of 5-10-5, 16-20-0, 10-20-10 or 5-20-10, depending on soil test recommendations. NCS suggests applying light feedings of 5-10-10 or 10-20-20 starter mix shortly after seeds emerge. Soil chemistry and fertility should determine fertilizer type, application method and mixture rate.
Fertilizer runoff in storm water is a major cause of stream pollution, leading to destructive algae bloom and de-oxygenation of ground waters and rivers. As of summer, 2010, 17 states, including Maine, Vermont, New York, Pennsylvania, Wisconsin, Florida and Washington had legislated limits and prohibitions on the use of phosphorous in fertilizers and cleaning compounds. Many followed Minnesota's lead in allowing phosphorus to be used only on new lawns. In addition to following directions carefully with any lawn chemical treatment, homeowners should check on their state's laws concerning phosphorous before using it in a starter fertilizer preparation.