The most important things you can do to care for your lawn is to mow frequently and water regularly. If you find that your lawn struggles to grow green and lush despite following these practices, do what the pros do and use dethatching and aerification machines to help improve the ground under your lawn.
Mow frequently to keep the grass at the proper height. Set the mower at 2.5 to 3.5 inches for bluegrass, perennial ryegrass and fine fescue. Tall fescue should be cut to 3 to 4 inches high and zoysia to 1 inch high. Mow areas in the shade a half- to 1-inch higher.
If you cut grass shorter than recommended, the root growth is restricted and the lawn is more susceptible to insect damage, diseases and drought. It is also less able to stand up to traffic, and weeds take hold more easily. Mow the grass often enough that you are removing only a third of the length of the grass in a single cutting.
Remove thatch every one to two years. The best time to dethatch bluegrass or fine fescue is in early spring or early fall when the grass is actively growing. Zoysia should be dethatched during the summer. Tall fescue and perennial ryegrass rarely need dethatching.
Rent a dethatching machine with blades that cut the thatch all the way to the surface of the soil. The types with flexible, rakelike tines that attach to your lawn mower are not effective in completely removing thatch. Push the power dethatching machine across the lawn in rows, first in one direction and then in a direction perpendicular to the first pass. Manually rake and remove thatch that has been loosened. It can be composted or used as mulch in flower or vegetable beds.
Use an aerification machine every one to two years. Bluegrass, perannial ryegrass, fine fescue and tall fescue should be aerified in spring or fall when the lawn is actively growing. Aerify zoysia in early to mid-summer.
Rent an aerification machine that has reciprocating arms and uses the largest tines or spoons available for attachment to the machine. The ideal is to remove plugs of soil that are 2 to 3 inches deep and to punch 20 to 40 holes in every square foot of lawn area. If the machine you rented does not create this many holes, make subsequent passes across the lawn until you reach this amount. Push the machine across the lawn in rows first in one direction, then in the direction perpendicular to it.
Fertilize your lawn three times per growing season. Put down the first application in mid-spring, early to mid-May in most areas of the U.S. The second application should be applied in late summer, about the first of September. The final application should be put down in late fall, about mid- to late November.
Apply high nitrogen fertilizer according to the manufacturer's recommended application rates. Use a drop spreader and set the release rate to that recommended by the fertilizer manufacturer. Do not apply fertilizer to wet grass. Water the lawn immediately after putting down the fertilizer to wash it off the blades of grass and prevent the fertilizer from burning the plants.
Apply weed killer along with the spring application of fertilizer to control weeds. Follow the manufacturer's recommended application rates. Thereafter, the best way to control weeds is to mow frequently, dethatch and aerify regularly, and hand pull any stray weeds before they go to seed.
Water regularly. Lawns need a minimum of 1 to 2 inches of rainfall per week. Water thoroughly and deeply every time you water, so the soil is damp to a depth of 4 to 6 inches. Light, frequent watering encourages shallower roots, making the lawn more sensitive to the slightest drought.
Water in early morning to decrease the evaporation rate of the water and to reduce the chances of lawn diseases or fungus taking hold if the grass is damp overnight. The best way to water a lawn is with an overhead sprinkler or sprinkler heads in an irrigation system.