Maintaining a Healthy Lawn

Expanses of weed-free, perfectly groomed grass do not occur naturally; they require careful attention and consistent care. Along with the routine demands of mowing and watering, other periodic tasks such as fertilizing, aerating, and dethatching are also necessary to keep the grass green and healthy.


There are a wide variety of mowers available; choose the one that best suits your needs. Sharpen the blade yearly (page 11) and keep the lawn free of debris that might dull the blade or be thrown out of the mower’s chute. Before starting the engine, adjust the cutting height (page 50). Recommended mowing heights for the most common lawn grasses are given in the appendix.

Lawn clippings can be bagged, but short clippings left on the lawn decompose to a natural fertilizer. Modern mulching mowers, which have a special blade and a fully enclosed deck, chop clippings fine to speed decomposition; you may be able to convert an older mower to work like a mulcher.

For a finished appearance, crop around posts and other hard-to-reach areas with a power trimmer, and use an edger to cut a small, narrow trench along flower beds and sidewalks (page 51).


In summer, when high heat and lower rainfall slow the growth of grass, you will mow your lawn less often but water it more. A thorough watering—perhaps once a week—is preferable to frequent light waterings, which can inhibit the growth of deep roots. Control the amount of water the lawn receives by setting your sprinkler for the correct intensity and area.

Grass does not, of course, live by water alone. To replace soil nutrients, fertilizers must be added. The timing depends on the type of grass, as indicated in the grasses chart. Always sweep excess fertilizer from sidewalks and driveways onto the lawn to prevent runoff into storm drains.


Even in the best-kept lawn, a few weeds are inevitable and must be dug up or destroyed with a selective herbicide that kills weeds without harming grass. Some weed-killers wither parts of the plant they touch. Others are systemic: they are absorbed into the plant, destroying even the roots. Weed-killers can be applied directly to isolated weeds or they can be sprayed over an entire area that is badly infested (pages 57-58).

Most large garden centers carry water-soluble, environmentally safe dyes that when mixed with herbicides in the sprayer help ensure even coverage. Rain or watering soon washes the dye away.


Despite careful watering and fertilizing, a lawn may still deteriorate if thatch—a matted layer of dead grass—becomes too thick, strangling new growth. Strip it off with a thatch rake or a power dethatcher (page 60); both devices cut slits through the tightly woven barrier so it can easily be raked away.

The soil in heavily used backyards or play areas can become so compacted that grass roots cannot penetrate it. An aerator (page 61), which extracts small plugs of earth to loosen compacted soil, may be needed as often as every 2 years. Periodic aeration also helps prevent thatch buildup.

Compost is an excellent soil amendment, or additive, when raked into the holes left by the aerator. Contact your local extension service to see if composted municipal sludge is available in your area.

TOOLS Tape measure Screwdriver Weeding fork Spading fork Garden rake Hoe Garden trowel Thatch rake or power dethatcher Grass rake Aerating fork or power aerator MATERIALS Lawn fertilizer Grass seed Weed-killer Stakes String Peat moss Composted municipal sludge Straw or wood fiber mulch Chain-link fencing


Before repairing or adjusting power lawn-care equipment, always unplug an electrically powered machine, or if it has a gasoline engine, disconnect the spark plug wire.


When using lawn-care machinery wear sturdy leather shoes (preferably steel-tipped), long pants, goggles, and gloves. Also protect your ears when operating loud gasoline-powered machines. Wear gloves when using hand tools to dig or rake.



A reel mower

The scissoring action of reel blades against a fixed metal bed knife makes a smooth cut, particularly on thin grasses such as bluegrass. Reel mowers are less effective in trimming denser grasses such as zoysia. The blades need frequent sharpening and are easily damaged by twigs or pebbles. In addition to the manual mower shown here, there are also self-propelled power models. Both types are best suited for small, level lawns.

The versatile rotary mower

A walk-behind mower like the one shown at right cuts a clean swath through any type of grass and allows you to bag your clippings, discharge them, or mulch them. Similar features are available in riding mowers, which may be worth their extra cost for lawns larger than ½ acre. Essential to mulching is a mulching blade (photograph), which is specially curved to lift and slice the grass repeatedly over a long cutting edge.


A power trimmer

Available in gas, plug-in, or battery-powered models, this tool is handy for cropping grass around posts and other obstacles to lawn mowers. A rotating nylon cord lops off grass with a whipping action. Cord frayed through use is replaced from a reel in the cutting head, which when tapped on the ground releases a length of fresh cord. A cutter on the safety guard trims the cord to the correct length.


A power edger

Trimming along a walk or driveway with an electric or gasoline-powered edger gives a neat, finished look to a lawn. A metal edge guide prevents the machine from wandering while the spinning blade digs a shallow trench along the edge.




Setting the mower blade height

Roll the lawn mower onto a driveway or sidewalk and detach the spark plug wire. (Unplug electric models.) Reach into the discharge chute and rotate the blade so that one end is toward you, then measure the distance from the blade to the ground. Move the height-adjustment levers (right), raising or lowering the deck to achieve the desired blade height—usually between 1 and 2 inches.

Mowing on level lawns and slopes

On a level lawn, the choice of mowing pattern is up to you. But whether you cut in parallel strips up and down the lawn or in an elongated spiral as shown at left, remember that mowing affects the direction in which grass grows and leans. To prevent stripes in the lawn, change the direction of the pattern each time you mow. To mow safely on a hillside (inset), begin at the top of the slope, and guide a walk-behind power mower across it in parallel lines. With a riding mower, drive up and down the slope for the best stability.


Trimming around obstacles

Hold the power trimmer’s cutting head parallel to the ground, an inch or so above the soil, and swing the cutter back and forth in smooth passes, working toward the obstacle.


Cuttinq a clean edqe

For short lengths of edging along sidewalks, driveways, and flower beds, a manual rotary edger may be sufficient, but for bigger jobs, use a power edger (right). If the blade of your edger is adjustable, set it to the desired depth. Then position the edger so the wheels are on the hard surface. Turn on the machine and walk at a steady pace, pressing the guide against the edge of the pavement or border.




An oscillating sprinkler

Driven by water pressure from a garden hose, an oscillating sprinkler provides an even dousing of a rectangular area of grass. The perforated, curved crosspiece swings back and forth through all or part of an arc; controls at the base of the crosspiece set the sprinkler to water all of the lawn, the center alone, or either half (shaded areas, left).


To check the quantity and distribution of water from your sprinkler, set several shallow containers, such as empty tuna cans, throughout the area to be watered, then run the sprinkler for an hour at the same time of day you water the lawn. You should expect to collect 1 inch of water in an hour, and the amounts of water in each can should be almost equal.

Test for water penetration by pushing a screwdriver tip into the lawn 24 hours after watering it. If you encounter resistance before the tip reaches a depth of 6 inches, water the lawn longer.

A turret sprinkler

Multiple sprinkler heads on the turret spray rectangular patterns of different lengths and widths. Compared with an oscillator, a turret sprinkler provides a dousing that is quick, heavy, and somewhat uneven.


A pulsating sprinkler

The head of this sprinkler waters grass in a circular pattern that can be adjusted from a narrow wedge to a full circle. The sprinkler head is constantly in motion to prevent water from pooling, and the stream can be varied from a fine spray for small areas to a heavy, longer-range jet.


A traveling sprinkler

This self-propelled sprinkler is ideal for long, narrow lawns. Using its own hose as a track, it creeps along the route even uphill, while the spinning nozzles soak the grass. The traveling sprinkler shown here drags its hose behind it; other models reel in the slack hose as they move across the grass.


A sprinkler hose

Tiny holes along the top of the hose provide a fine, soaking mist. The flexible hose is especially suited for very narrow areas. It can also be laid to match an irregular plot’s contours (left).




Calculating the quantity

To determine how much fertilizer you need for your lawn, divide the grassy area into rough geometric shapes such as rectangles, circles, and triangles (above). Calculate the area of each section, then add those figures together. Small areas outside the lawn that happen to be included in this estimate tend to compensate for grassy patches that are left out.

Using a trough spreader

Set the spreader gauge according to the instructions on the fertilizer package. At a corner of the lawn, open the trough with the release lever and immediately start walking at an even, moderate pace along one side of the lawn. Close the trough when you reach the far end to avoid burning the grass with excess fertilizer. Turn the spreader around and position it so that the next row touches but does not overlap the first. Open the trough and run the second row, then make two similar rows at the opposite end of the lawn (inset). Fill in the remaining area by running rows perpendicular to the end rows, being careful not to overlap the fertilizer at any point.



Lawn fertilizers come in liquid, pellet, and granular form, with labels that rate the nitrogen, phosphorus, and potassium content according to a three-number code. For example, one common rating, 10-6-4, indicates that 10 percent of the fertilizer bulk is nitrogen, 6 percent phosphorus, and 4 percent potassium. Make a soil test (page 39) annually to check for deficiency in any of these three minerals. If the soil is found wanting in one of them, use fertilizer with a higher proportion of the mineral in short supply.

Liquid fertilizer is easy to apply, but the nutrients leach through the soil quickly, necessitating frequent reapplication. Although time-release pellets last 6 months or more, they are costly and slow acting. The more common choice is dry granular fertilizer because it is quick, reliable, and relatively inexpensive.

Using a broadcast spreader

Calibrate the spreader according to the fertilizer directions, then, beginning at a corner of the lawn, push the spreader at a steady pace that scatters fertilizer 3 or 4 feet to each side. Work up and down the lawn in wide parallel sweeps. To ensure full coverage near the edges of the path where the fertilizer falls less densely, overlap the rows by about 1 foot. Approach corners and boundaries close enough to give them full coverage. Repeat the pattern at a right angle to the original rows (inset).



Fertilizers, weed-killers, and other chemicals can be harmful if they come in contact with the skin. Read the labels carefully and follow their recommendations. In addition to long pants and a long-sleeved shirt, it is advisable to wear rubber gloves and eye protection. A dust mask traps particles of dry fertilizers.



A weeding fork

If the soil around the weed is hard, soften it by watering over a period of days. Grasp the runners or leaves in one hand; with the other, push a weeding fork 3 or 4 inches into the earth alongside the main root. For an unusually stubborn weed, dig the fork all the way around it, trying not to tear the leaves or break the roots. Lever the fork in the surrounding soil to work the roots free, then pull up lightly on the bunched leaves to remove the weed with its roots intact. Sprinkle a few grass seeds in the hole that has been left by the weed.

A trigger sprayer

Hold the bottle of weed-killer above the weed, and spray directly onto the center of the plant, coating the leaves and main stem. Allow 2 to 4 weeks for the weed to shrivel and die, then remove it.



  • ✔ Unless an area is badly infested with weeds, spot-treat individual plants rather than treating the entire area.
  • ✔ Spray weed-killers on calm, still days.
  • ✔ To expose the greatest surface area of the weed to the weed-killer, postpone mowing until at least 2 days after applying the chemical.
  • ✔ Keep clippings from grass that has been treated with weed-killers out of mulch or compost used in gardens or around shrubs. Residual chemicals may harm other plants.
  • ✔ Observe the cautions noted on page 56.


    Using a pressurized sprayer

    Along one end of the weed-infested area, mark off a 3-yard strip with a pair of staked parallel strings. Build up pressure in the sprayer with a few strokes of the hand pump, then spray the area between the strings, holding the wand about 12 inches above the lawn and moving it quickly and steadily for a light, even coverage. Move one of the strings to mark off an adjoining strip, and treat this area in the same way. Continue spraying strips until you have covered the entire area.

    Using a garden-hose sprayer

    Read the weed-killer’s label to see how many square feet one jarful will cover, mark off that area with string and stakes, then run a string down the middle to divide it in half. Fill the sprayer jar with the weed-killer-and-water mixture specified in the label instructions; then screw the sprayer nozzle onto a garden hose and attach the jar to the nozzle. Turn on the hose and start the flow of weed-killer by covering the air-siphon hole with your thumb or by depressing the trigger, depending on your model. Spray half the weed-killer evenly on one side of the string, then apply the remainder on the other side.




    Preparing the soil

    Turn the soil in the plot with a spading fork, digging 5 or 6 inches deep. Remove 3 inches of soil and work the remainder to break up clods. Dust the area lightly with lawn fertilizer and add a 3-inch layer of composted municipal sludge or peat moss, then use the spading fork to mix it thoroughly with the underlying soil. Make the soil even with the surrounding earth by tamping it down with your foot. If necessary, adjust the soil level, either by removing mix or by adding and tamping down more made from the 3 inches of soil removed from the area. Smooth the surface of the soil with the back of a garden rake.

    Reseeding the patch

    With your thumb and forefinger, sprinkle grass seeds ⅛ inch apart over the patch (right). Work the seeds into the top ⅛ inch of soil mix with a garden rake, then tamp the soil lightly with the back of a hoe. Cover the patch with a thin layer of straw—half the soil should show through—to protect the seeds from birds and wind, and lightly mist the area with a garden hose.




    Checking for thatch buildup

    Pierce the lawn with a garden trowel and pull the slit open to expose the layers of grass, roots, and soil (right). Check for a matted layer of densely intertwined roots and dead grass between the green blades and the soil (inset). If this layer is thicker than ½ inch, dethatch the lawn.

    Dethatching the lawn

    For a small plot, work in rows about 2 feet wide with a thatch rake (above, left). Hold the rake at a 30-degree angle and press the teeth through the thatch. Pull the rake through the grass to dislodge the thatch. For large areas, rent a self-propelled power dethatcher (above, right). At the center of the lawn, pull the height lever to lower the blades into the thatch, then turn the adjustment knob until the blades barely penetrate the soil. Engage the clutch, then run the machine over the lawn. Follow the pattern used for mowing (page 50), but do not overlap the rows. Remove the thatch with a flexible grass rake.




    Aerating the lawn

    Mow the lawn and saturate the ground with a sprinkler a day in advance of when you plan to aerate. For a small lawn, thrust an aerating fork with three or four tines (above, left) into the ground at 6-inch intervals; try to penetrate to a depth of at least 3 inches. If the soil is too compacted, make a shallower pass, resoak the lawn, and try again. Work along one boundary, and then back and forth parallel to this line, leaving the extracted cores scattered on the ground. For large areas, rent a power aerator (above, right). Beginning at the center of the lawn, start the aerator’s engine and warm it up with the clutch disengaged. Engage the clutch to start the corer drum, and guide the aerator in the pattern that is used for mowing, but do not overlap rows. In particularly hard soil you may need to increase penetration either by adding water to the corer drum or by attaching weights, if they were provided, or both.

    Crumbling the cores

    For a small area, use the back of a garden rake to break up the cores (left) and spread a ½-inch layer of composted municipal sludge or other soil amendment over the area, filling the core holes. Water the lawn thoroughly. For larger lawns, drag a section of chain-link fencing across the lawn—either by hand or attached to a lawn tractor—to break up the cores.