Lawn Problems

Knowledgebase

Lawn problems can occur in small areas or larger patches, or entire lawns can die. Sometimes the problems are due to poor growing conditions, improper lawn care practices, or extreme weather conditions. The following is a guide to help you decide what conditions may be causing problems in your lawn.

After Winter but Before Spring Green-Up

Sign/Symptom	Cause	Prevention/Treatment
Large areas of straw-colored grass, especially where exposed to wind with little snow cover.	Winter desiccation
New leaves killed back	Spring frost damage
White, pink, and gray mold in circular patches on moist grass	Snow molds	In Spring: Rake away dead grass. In Fall and Winter: - Avoid snow molds by mowing until grass stops growing in the fall. - Avoid fall nitrogen applications as they will delay dormancy. - Prevent deep piling of snow along walks and driveways where there is grass
Dead or yellowed grass along sidewalks, driveways, or roads where salt has been applied	Salt damage	- Water heavily to try to wash Salt damage - Water heavily to try to washaway salt - Reseed where the lawn is thin. - Avoid salt when possible; try sand, urea, environmentally-safe deicing chemicals, etc. as a substitute for salt.

After Spring Green-Up

Soil

Compaction

- Aerate the soil.

- Add organic matter during lawn reconstruction.

- Reroute foot traffic and play areas to avoid frequent packing down of soil.

Have soil pH tested and adjust pH as recommended.

Low nutrient levels (yellowed, slow-growing lawn)

- A balanced fertilizer of nitrogen/phosphorus/potassium promotes a healthy lawn.

- Have soil pH tested and adjust pH as recommended.

Improper fertilizer application

The wrong amount of fertilizer can result when the spreader is not calibrated properly. Take special care when changing directions while spreading. Brown streaks lined with extra green growth can occur in areas of application overlap. Yellow, nutrient-deficient streaks may occur in missed areas.

Dog urine (Spots of brown grass, perhaps with green area around them.)

Train your dog or provide a dedicated outside kennel.

Chemical damage Many household chemicals, salt, oil, gasoline, concentrated fertilizers, herbicides, and gas leaks can cause sudden scorched areas in lawns at spill sites.

Thatch

- Remove thatch layer if more than ½-inch thick. Thatch harbors pathogens and insect pests and prevents grass plants from properly absorbing nutrients and water.

- Prevent thatch by avoiding excess fertilizer and fungicide applications.

Water

- Water deeply (to a depth of 6 inches) when necessary—generally, 1 inch per week.

- Water early in the day so foliage will dry quickly. Night watering (after dew appears) is not recommended during very hot, humid weather.

- If you apply too little water, wilt (blue-green color and footprints easily visible), browning, and death can occur. Some grasses (e.g., Kentucky bluegrass) will go into dormancy in drought but will green-up again when moisture returns.

- Too much water deprives roots of oxygen, stunts growth, and promotes root and crown rots.

Light

- Most lawn grasses will be thin and weak in shaded areas; use shade-tolerant grass seed mix.

- Selective pruning of tree branches may let in enough extra light to promote grass growth.

- Plant groundcovers in heavy shade.

Mowing

Height

- Mow at 2½ to 3 inches, with maximum in hot, dry weather.

- Avoid 'scalping,' especially in irregular, bumpy areas. Repair these areas when they occur.

Frequency

Cut no more than one third of total length at any cutting so grass is not stressed.

Clippings

Clippings can generally be left except during a disease outbreak.

Equipment

If grass blades look brown and shredded at the tips after mowing sharpen and adjust mower blades. Mower should

be sharpened at least once a year.

Insects

White grubs: Lawn shows gradually increasing patches of thin grass; it often looks like drought stress, sometimes accompanied by skunk or raccoon damage (lawn torn out in chunks because animals are feeding on the grubs). This is usually observed from May to early June or in September and October when grubs come up to the soil surface to feed on grass roots.

Chinch bugs: Generally, these are observed in sunny areas or on sandy soils. The problem is often confused with drought stress as it is usually observed during hot periods in July and August.

Bluegrass billbugs: This is sporadic in New England. It usually begins as yellow areas of grass along the edges of driveways and sidewalks and is usually observed in July or early August. Adults may be seen on pavement in late May or early June.

Sod webworms: Adults are small moths that fly just above the ground at dusk. Damaged areas begin as small discreet patches that can spread into larger areas. Feeding by caterpillars occurs at night.

Disease

Circular patches and/or rings of dead and/or unusually green grass	- Note size and patterns. - In the morning, when grass is still dewy, look for the web-like threads of the fungus and/or mushrooms on the lawn. - Dig up a section of dying grass and examine the roots for dark color and evidence of crown and root rot.
Thin or dead grass in an irregular area	Examine individual grass blades for: (1) leaf spots (probably tan with dark borders); (2) evidence of fungus (orange, black, or white powdery spores); (3) gelatinous red threads; and (4) slimy or powdery white, orange or brown mold.