Lawn care

The average homeowner spends 3.8 hours a week on yard work and mows their lawn 30 times a year. You may not realize it, but your lawn pays you back for all this hard work. It serves as a giant air conditioner to help cool your home. It releases a tremendous amount of oxygen and captures tons of dirt and dust to help keep you and your family healthy.  And the healthier your lawn is, the better it keeps up its end of the bargain.

The good news is, you don’t have to slave over your lawn to keep it healthy. In fact, to a great extent, it’s not the amount of work you put into your lawn—it’s when and how you do it. The following five “ingredients” are essential for a healthy lawn.

1. Adjust your cutting height to the time of year (and use a sharp blade)

For cool-climate grasses, use a 1-1/2 in. cutting height for the first mowing of the year to remove dead grass and allow more sunlight to reach the crowns of the grass plants. Raise the blade during the heat of summer to 2 or more inches. Then lower the blade back to 1-1/2 in. for the last cutting of the year. For warm-climate grasses, these heights will be about 1/2 in. lower.

When adjusting your blade height, measure from a hard surface to the bottom of the mower deck, then add 1/4 in. (most blades sit 1/4 in. above the bottom of the deck).

Cut your grass using a sharp blade. A dull one tears grass rather than cutting it cleanly. Damaged grass turns yellow, requires more water and nutrients to recover, and is more susceptible to disease. Sharpening and balancing a blade three times a year is usually enough to maintain a good cutting edge—unless you hit lots of rocks.

Ideal mowing height ranges

COOL CLIMATE GRASSES
Bent grass    1/4 to 3/4 in.
Chewing hard or red fescue   1-1/2 to 2-1/2 in.
Tall fescue   1-1/2 to 3 in.
Kentucky bluegrass   1-1/2 to 3 in.
Perennial ryegrass   1-1/2 to 3 in.

WARM CLIMATE GRASSES
Bahia grass   2 to 3 in.
Bermuda grass   1/2 to 1 in.
Blue grama grass   2 to 3 in.
Buffalo grass   2 to 3 in.
Carpetgrass   1 to 2 in.
Centipedegrass   1 to 2 in.
St. Augustinegrass   1 to 3 in.
Zoysia grass   1/2 to 1 in.

2. A few good soakings are better than lots of light sprinklings (but not in the evening)

Deep watering helps develop deep roots that tap into subsurface water supplies. Light sprinklings wet only the grass and surface of the soil; this encourages shallow root growth and increases the need for more frequent watering. As a general rule, lawns require 1 to 2 in. of water per week (from you or Mother Nature), applied at three-or four-day intervals. But this varies drastically depending on the temperature, type of grass and soil conditions. Lawns in sandy soils may need twice as much water, since they drain quickly. Lawns in slow-draining clay soils may need only half as much.

When your lawn loses its bounce or resiliency, or when it wilts, exposing the dull green bottoms of the blades, it needs water. As a general game plan, water until the soil is moist 4 to 5 in. down, then wait to water again until the top 1 or 2 in. of soil dries out. To find out how much water your sprinkler delivers, set out a cake pan, turn on your sprinkler, then time how long it takes for the water to reach a depth of 1 in.
Rotary sprinklers generally give better coverage than oscillating sprinklers, and are suitable for more soil types. You can reduce the water volume for slower watering of poorly absorbing, heavy clay soils, or increase the volume for faster absorbing sand or loam soils. The goal is to make sure all the water is absorbed, not running away from the garden. While reducing water volume does reduce coverage, it adds versatility beyond your garden. Your sprinkler will fit smaller flower beds or limited landscaped areas.

The best time of day to water is early morning. Water pressure is high, less water is lost to evaporation and your lawn has plenty of time to dry out before nightfall. Lawns that remain wet overnight are more susceptible to disease caused by moisture-loving mold and other fungi. 

Lawns that receive an initial soaking 4 to 5 in. deep, and are then watered when the top 1 to 2 in. of soil dries out, develop deep, healthy grass roots. This usually means applying 1 to 2 in. of water per week at three-or four-day intervals. An impact sprinkler delivers water quickly, with less “hang time” for evaporation; a 3/4-in. hose delivers much more water volume than its 1/2-in. cousin.  Daily waterings promote shallow root growth. Oscillating sprinklers toss water in a high arc, so more evaporates before reaching the soil.

3. Mow only the top one-third of the grass blade (and don’t rake up the clippings)

The top one-third of a blade of grass is thin and “leafy,” decomposes quickly when cut and can contribute up to one-third of the nitrogen your lawn needs. While it’s decomposing, this light layer of clippings also helps slow water evaporation and keeps weeds from germinating.

But the bottom two-thirds of a blade of grass is tough, “stemmy” and slow to decompose. It contributes to thatch, which—when thick enough—prevents sunlight, air, water and nutrients from reaching the soil. Cutting more than the top third also shocks grass roots and exposes stems, which tend to burn in direct sunlight.

This means if 2 in. is your target grass length, cut it when it reaches 3 in. Since grass grows at different rates at different times of the year, “every Saturday” isn’t necessarily the best time to mow. Sometimes you need to mow it more; other times, less. The ideal length for cool-climate grasses is 3 to 4 in.; for warm climate, 1 to 2 in.

Mow when the grass is dry and avoid mowing in the heat of the day when you’re more likely to stress the grass—and yourself.

4. Timing is everything when it comes to fertilizers and weed killers

When applying weed killers and fertilizers, you must take into account such variables as geographic location, grass type, weed type and soil conditions. But here are a few general guidelines:

The best defense against weeds is a thick, healthy lawn that doesn’t provide weed seeds adequate sunlight or open space to germinate.

Attack weeds in the early spring and summer before they have a chance to develop deep root systems, go to seed or reproduce.

Different weeds need to be dealt with using different chemicals and methods. It’s best to eradicate grassy weeds like crabgrass with preemergent weed killers, which destroy germinating plants just as they sprout. Broadleaf weeds need to be attacked while they’re young and actively growing; spraying the leaves of individual plants or patches of plants is most effective. Dandelion killers work by literally growing the plant to death.

Fertilize in early spring to jump-start root development. Fall feedings help repair summer damage and spur the root growth that goes on for several weeks even after the top growth stops; this helps grass survive the winter. Light feedings in between help maintain healthy growth.

Read the package. Some chemicals work only in the presence of moisture; other chemicals are rendered useless by water. Heed the safety warnings too.

The best resource for identifying and troubleshooting weeds is a nursery or garden center familiar with local conditions.

5. Aerate your lawn to help it "breathe"

Grass roots need oxygen as well as water and nutrients. A compacted lawn has trouble absorbing air, water and nutrients.  Aerating—the process of removing small plugs of soil—produces multiple benefits. It improves air-to-soil interaction. It allows water and fertilizer to penetrate the soil deeper and easier. It reduces soil compaction and opens space for roots to grow. It removes some thatch and stimulates the breakdown of the remaining thatch. The best tool for this task is a gas-powered aerator, available at most rental centers.

Again, timing is critical. You can aerate in the spring. But fall—after the kids are through trampling the grass and there are fewer weed seeds to set up home in the open spaces—is the best time to aerate. It’s usually best to aerate first, then apply any weed killers so the open holes are protected against weeds.


A well-aerated lawn provides space for grass roots to grow, reproduce and take in more oxygen, moisture and nutrients. The plugs, composed of thatch and soil, quickly break apart and decompose.

Prepare soil for reseeding using a power rake. Its solid tines slash through any thatch mat and score the surface of the soil. Power-rake only after aeration and in the afternoon, after the morning dew has dried—so the dead grass and roots lift out loosely without clumping. Make two opposing passes with the power rake, each 45 degrees across the pattern used by the power aerator.


Between passes with the power rake, always use a hand rake to loosen dead grass and lawn debris to ensure that new seed or fertilizer will contact the soil. If you reseed your lawn, make two passes with a rotary spreader. Each pass should contain half the recommended lawn seed for your square footage of lawn. Run it after each time you hand-rake in the same direction the power rake slit the soil so more seed can drop into the core holes and slits without being raked off.

 For more information

Growing a great lawn
Tune up a lawnmower
Major league look for your lawn
Cures for a patchy lawn
Sharpen your lawn mower blade
Seeding a bare spot
Efficient lawn sprinkers
Install an irrigation system
Move an irrigation system sprinkler head
Eliminate weeds from your grass
Choosing a lawn service