Whether seeding, plugging or sodding a new lawn, nitrogen-rich lawn starter fertilizer should be used before planting and again at least several weeks after planting. Amending the planting soil will help to compensate for nutrient loss due to all of the applied water. Starter fertilizer applied a few weeks after planting, when the lawn plants have already rooted in well, helps to spur abundant and lush green top growth.
Determine the proper amount of lawn starter fertilizer to use by consulting the product package label. It will help you calculate the amount of fertilizer for your square footage of planting bed or new lawn. Never exceed the rate of 1 lb. for every 1,000 square feet of lawn expanse unless using a slow-release fertilizer product. Excess nitrogen can cause burn and weak top growth at the expense of healthy root development.
Fill a drop spreader with the recommended amount of fertilizer, then set the aperture to the recommended drop rate from the fertilizer label. Start at one end of the planting bed or lawn, and walk at a consistent pace in straight, slightly overlapping rows over the entire area. Disengage the drop mechanism while executing turns to prevent too much fertilizer from being released.
Water the fertilizer and surrounding soil until it is all uniformly drenched with water to a depth of at least 6 inches. Keep the soil evenly moist at all times while the lawn is knitting in and establishing itself.
Repeat the after-planting fertilizer application, waiting at least three weeks and up to eight weeks for the roots to develop and spread down into the soil. Applying the second dose of fertilizer too soon risks chemical burn, but also a diversion of nutrients and plant energy away from root development, which is critical to a healthy lawn over the long-term.