A newly seeded or sodded lawn should be mowed when the grass reaches a height of 3 inches. Mow to a height of 2 inches and return or remove the clippings depending on the quantity. An application of 0.5 to 1.0 pound nitrogen per 1,000 square feet 3 to 5 weeks after seeding will improve establishment. The lawn should be irrigated immediately following the nitrogen application.
Herbicides are not recommended for weed control on a newly seeded lawn until after it has been mowed at least 3 times. Even then, herbicides must be used at minimum rates and with caution. Follow label directions carefully.