Fix Lawn Spots

5 Remedies for your hurting turf

Improve your lawn's natural defenses and reduce future maintenance chores with these common sense cures for spots, thatch, fairy rings, grubs and shade.

By the DIY experts of The Family Handyman Magazine

Problem: Dog spots on grass

Symptoms: Dog spots are round patches about 4 to 8 in. in diameter with dead grass in the middle, encircled by dark green grass. They’re most apparent in the early spring when dormant grass first begins to turn green again.

Cause: Dog urine contains high concentrations of acids, salts and nitrogen, which burn (dry out) the grass roots and kill them. As rain washes the area, the urine is diluted and the nitrogen spreads, causing the grass surrounding the spot to grow faster and turn greener.

Remedy: You have to replant your grass; it won't come back on its own. But first you have to dilute or remove the caustic urine from the soil (Photo 1). Thoroughly soak the area with lots of water. Let the hose run for at least three minutes. Then you can start the replanting process (Photo 2). Add a half inch of new soil to help absorb any remaining urine (Photo 3). Then you can spread new seed, as we show, or use a commercial yard patch mixture (available at most nurseries or home centers) or even sod. In any case, the secret of good germination is keeping the seed moist. And keep the area moist until the new grass is about 3 in. high.

When you're watering new seed, moisten the soil daily and keep it damp—but don't soak it. Overwatering is a common mistake.

Recovery time: Four to six weeks.

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Problem: Thatch

Symptoms: If your grass feels soft and spongy when you walk on it, your lawn may have a thatch buildup. Thatch is a fibrous mat of dead stalks and roots that settles between the lawn's green leaves and the soil (photo above). When this mat becomes greater than 3/4 in. thick, it can cause your lawn to suffer from heat and drought. Affected lawns will rapidly wilt and turn blue-green, indicating they're hot and dry.

Cause: Cutting off too much at each mowing (letting the grass get too long) and cutting too low. Both will produce more dead grass tissue than microbes and earthworms can recycle. Thatch can develop in any soil but is most often associated with high clay content. Other causes are overfertilization and frequent, light watering, which encourage a shallow root system.

Remedy: Slice open a section of your lawn (Photo 1). If your grass shows 3/4 in. or more of thatch, it's time to rent an aerator. An aerator is a heavy machine that opens the soil by pulling up finger-size soil cores. The lawn will absorb more oxygen and water, which will encourage healthy microbe growth and give worms wiggle room.

Aerate in the spring or fall when the grass is growing but the weather is not too hot to stress the plants (Photo 2). If the machine isn't pulling plugs, your lawn may be too dry. To avoid this problem, water thoroughly the day before you aerate. You can also rake in topsoil (Photo 3) to increase the healthy microorganisms that aid thatch's natural decomposition. Topsoil is available at any garden center.

Recovery time: You can expect the thatch layer to decrease by about 1/4 in. per year, about the same rate at which it forms.

Renting a Lawn Aerator

If your goal is to have one of the nicest lawns on the block, you can go a long way toward achieving it with annual aeration.

When a lawn lacks sufficient air (a “compacted” condition), it grows slowly and becomes vulnerable to disease, insects and heat damage. The soil will become impermeable and shed water instead of absorbing it.

Gas-powered aerators are available at most tool rental stores. They're slow-moving but powerful machines, so ask the clerk for handling directions. An aerator weighs about 200 lbs., so be prepared for some heavy lifting or ask your rental store for a ramp to get it into a truck bed or van.

Cool-season grasses should be aerated in the late summer or early fall. Spring is best for warm-season types. (If you're not sure what type you have, take a sample to an expert at a local garden center.)

Resist the temptation to remove the thatch with a rented power rake. Power raking is less effective than aerating because it typically removes less than 15 percent of thatch and may damage the healthy grass as well.

Aerator
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Problem: Fairy Ring

Symptoms: Fairy rings are circles approximately 3 to 8 ft. wide that consist of a dark green and fast-growing area of grass surrounding an inner area of partially dead or thin grass. Some rings also produce mushrooms.

Cause: Fairy rings are caused by fungi that live in the soil. As the fungi feed on organic matter, they release nitrogen, causing the grass to turn dark green. As the colony grows, it disturbs the flow of needed water to the turf roots, creating thin or dead spots. Fairy rings often begin with the decomposition of organic matter, such as an old tree stump buried under the lawn.

Remedy: By bringing up the color in the rest of your lawn with a nitrogen fertilizer, you can mask much of the overgreening of the fairy ring (Photo 1). Hand-aerating the ring will break up the fungus and allow the flow of water and other nutrients to the grass roots (Photo 2).

Recovery time: Generally fairy rings can be masked with the application of fertilizer, with results in 10 to 14 days. The grass within the ring will thicken up with aeration in about two to three weeks.

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Problem: Grubs

Symptoms: Grub-chewed turf has patchy areas that wilt and die. You can easily pull up the affected turf if you tug on it. Another indicator of grubs may be increased raccoon, bird or mole activity. They like to dig up and eat the grubs at night. While this may sound good, the moles will kill the grass as they forage for grubs.

Cause: Lawn grubs are the larval stage of moths and beetles. The grubs eat the roots of grass, setting them up for death by dehydration.

Remedy: Be vigilant. Are beetles swarming around your porch light? In the next month, keep an eye out for patches of grass that wilt or are blue-green on hot days. They may be larvae infested. Turn over some turf (Photo 1). If you count six to 10 grubs (white wormlike larvae with black heads) under a 1-ft.-square area of sod, consider using a grub insecticide (available at home centers and nurseries). Or talk to a professional (search “Grass Service” online) about treating your yard. They will be familiar with the grub problems in your region and the most suitable treatment methods.

If you spot the grubs but your count is lower than six per square foot, baby your lawn to strengthen its natural defenses. Mow on higher blade settings and water thoroughly but infrequently to encourage the grass to grow new, deep roots. Do not cut off more than one-third of the grass height at each mowing, to avoid stressing the plant.

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Problem: Shade

Symptoms: Shaded grass will look thin and patchy. Some types of grass actually produce wider blades as the plant attempts to catch more rays. But they also produce far fewer blades, lending a spindly appearance to the lawn. The cold truth is, if your lawn gets less than six to eight hours of sun daily, you are unlikely to sustain lush grass.

Cause: Trees, buildings and bushes.

Remedy:There are no good remedies. You can increase the sunlight as much as possible by trimming trees and shrubs. Also try starting areas in shade with sod instead of seed. The sod will adjust to the lower level of light. Although all seed varieties have their shade limitations, try overseeding your thin area with a shady grass mix.

Or throw in the towel, grab your trowel and plant a shade-tolerant ground cover. Many will thrive where your turf withered. Lamium (dead nettle) and ajuga (bugleweed) collaborate nicely in providing lovely blooms and an enthusiastic, but not invasive, carpet. This pair fares well, with a hearty tolerance spanning zones 3 to 8, and can be planted right up to your grass. They are fairly low growers and won't get more than a few nicks from a lawn mower.

Also, mulching between the ground cover plants will help retain moisture. This is especially wise if your new “shade garden” is on a slope; mulch will help prevent your fledging plants from washing out in a hard rain.

Recovery time: The plants and mulch will immediately boost the appearance of an area that was once thin grass. It'll take a couple of seasons for the ground cover to become established and blanket the area.

CAUTION

Call your local utility provider or 811 to mark your underground utility lines before you dig.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Broadcast spreader
  • Garden rake
  • Wheelbarrow
  • Spade

You'll also need a hand rake, a hand aerator, a power aerator, a hoe, and gardening gloves.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

  • Grass seed
  • Fertilizer
  • Insecticide
  • Topsoil