Water your lawn only when it begins to yellow, the grass blades begin to fold and imprints of shoes remain for days. Water your lawn by 9 a.m. to prevent the water from evaporating before reaching the roots. The sun will evaporate any extra water that isn't absorbed by the roots.
Mow your lawn as often as possible. Cutting your grass frequently will force it to grow thicker. The thicker your grass grows, the less room for weeds. Make sure your mower has sharp blades. Dull blades will only weaken your grass, making it prone to disease. Don't mow your lawn when it's wet, since it will create bald spots in your lawn.
Leave all mulch clippings on the lawn. There's no need to waste your time bagging and dumping clippings. These clippings will break down and fertilize the soil, making your grass healthier. If you mow your lawn often, there should not be many clippings.
You can also send a sample of your lawn's soil to a lab in your area. The lab tests the sample and can tell you the details of the soil's contents for a payment of about $20. Use this analysis to purchase fertilizer that will benefit your lawn. For example, you won't nitrogen fertilizer if the soil already has too much nitrogen. Purchase a hand-held fertilizer spreader to ensure even distribution.
Use a dandelion weeder to get rid of all the weeds in your lawn. Monitor your lawn for weeds and pick them when they first appear to ensure they don't get out of control.