As summer sizzles, your lawn can easily fizzle, trading lush green for ugly brown shades. The exact causes can vary. Insect feeding above or below ground, diseases, drought stress, soil compaction, improper fertilizing or other factors can combine with heat to damage grass. And once a lawn is weakened, it is even more susceptible to further attack by weeds and insects.
A little detective work can usually uncover the culprits behind brown summer lawns. If your lawn is turning brown, here’s how to identify the real problems and what to do to keep grass healthy.
Like most plants, grass reacts to summer's high temperatures and lack of water by wilting, turning brown, or even dying. Here's how to identify drought stress:
- Learn to recognize the early signs. Footprints will remain visible on a lawn after it's walked on. Kentucky Bluegrass and tall fescue develop a grayish cast, while other grasses become darker hued. All lose their bright green color. Grass blades may also wilt or curl.
- Go to a brown patch, and pull on the grass. If it won't pull easily from soil and is firmly rooted, drought may be the cause.
- Push a screwdriver or stiff rod into soil in brown and green lawn areas. If the blade slips easily into green lawn and won't penetrate brown, soil is dry in brown areas, probably due to uneven watering. In rocky soil, dig a small hole to check soil moisture. Watch your sprinklers run and look for problems. Learn more information on proper lawn irrigation.
- Look at the whole lawn. When drought or insufficient water is the problem, brown patches seem to appear randomly and in rough patterns. But if you look closer, grass near a sprinkler head may be green, while lawn further away or on a slope is brown. Grassy areas in shade can remain greener when areas in full sun are brown due to a lack of water. Lawn in low spots will stay green while higher or raised areas turn brown. Many of these symptoms are signs of a faulty irrigation system or inefficient watering.
During periods of hot, dry conditions, both cool- and warm-season grasses can naturally go dormant as a survival measure. If grass receives less than ideal amounts of water but still gets some, it may only grow slower and blades will remain green, although not as bright green. During times of prolonged drought without irrigation, grass often turns brown but is not dead. If grass turns brown, don't irrigate it unless you plan to continue watering for the entire summer. Shifting in and out of dormancy, depletes grass roots of food reserves, making plants susceptible to further stresses.
Don't let newly-planted lawns go dormant. With a limited root system, parts a new lawn might not survive dormancy.
It varies by region, grass type and severity of the drought conditions, but grass that's completely dormant may take up to 3-4 weeks, as irrigation is provided, to turn green. Providing more water than a lawn needs doesn't hasten recovery. Reseeding a lawn that has gone dormant, especially ones made up of cool-season grasses, will help get your lawn back to normal more quickly.
Lawns also turn brown during summer due to insect feeding. Insects that attack lawns during summer include White Grubs, Chinch Bugs, Sod Webworms, and Army Worms. Check with your local Cooperative Extension System office to learn which pests plague which grass types in your area and the best methods for control.
Fertilizing cool-season grasses in midsummer, cutting grass too low and overwatering can weaken turf to the point that the grass becomes thin, Inviting insects, weeds and diseases.
Compacted soil, which results in poorly-rooted grass that struggles to survive even when moisture is plentiful, can be caused by overuse or parked cars. Heavy clay soils can create the same results. Avoid heavy foot and vehicle traffic on lawns, especially during drought. Aeration is the best solution to compacted soil.
Lawns that are drought-stressed are more susceptible to disease organisms. Other conditions that predispose a lawn to disease include watering late in the day or at night and mowing with a dull blade. The ragged, torn edges offer more openings for disease organisms to enter grass blades.