Tips to a Weed Free Lawn
A dense stand of healthy grass will prevent weeds from invading your lawn. Weeds are "opportunists" they will grow in thin areas of the lawn. Simply altering the cultural practices to favor the growth of grass plants will reduce the chance of weeds invading your lawn. The cultural controls may include changing the mowing height, and/or the frequency of mowing, timing of fertilizer applications, adjusting your irrigation schedule, seeding thin spots, controlling insect damage, and aerifying the soil.
A combination of proper cultural practices plus careful use of herbicides may be necessary to control weeds effectively in your lawn. Contact your county Extension office or master gardener for more detailed lawn management information.