After a hot summer, a lawn can easily fizzle, trading lush green for crispy brown shades. The causes of brown grass vary. Insect feeding, drought stress, soil compaction, or other factors can combine with heat to damage grass. In this weakened state, a lawn is more susceptible to attack by weeds and insects.
Some simple detective work can uncover the culprits behind brown summer lawns. Learn what to look for when lawn brownouts occur and what to do to keep grass healthy.
Drought stressed grass looks blue-green or silver, and individual blades curl. Footprints remain in the lawn after you step on it and the soil under the lawn is dry. All turf can survive some drought stress, although some types of turf require less water than others.
Choose drought-tolerant turf grass. Irrigate efficiently.
Shade stress occurs when certain types of turf grass do not get enough sunlight and thin and disappear, leaving bare patches of soil and areas of weeds. Buffalo and Bermuda grasses do not grow well in shaded areas and are most susceptible to shade stress.
Choose shade-tolerate groundcovers or shade-tolerant turf grasses, such as St. Augustine or zoysia, for planting in shady areas. Thin out tree branches a bit to brighten shady areas. Raise the mowing height on your mower to allow more grass blade to capture sunlight.
Iron Chlorosis causes the blades of the grass to develop green and yellow stripes or to turn completely yellow. It occurs in alkaline soils with high phosphorus levels, and under cool and wet conditions.
Do not use fertilizers that are high in phosphorus. Topdress your turf with 1/4- to 1/3-inch of compost. Aerate your lawn once a year. For temporary relief, try adding iron supplements to your lawn.
Take all-patch first appears as a yellowing of the grass and a darkening of the grass roots, followed by a thinning of the turf in irregular shapes. It spreads mainly during the fall, winter, and spring, but its symptoms generally do not appear until the hot, stressful days of summer.
Maintain good drainage. Don’t overfertilize, as excessive nitrogen seems to promote take-all patch. Raise the mowing height on your mower to reduce stress on your turf. Don’t use broadleaf herbicide, which may weaken your turf. Also, avoid urea-based fertilizers.
Brown patch first causes circular patterns of dead grass blades. In a few weeks, new blades emerge in the center of the patch, causing a donut-like appearance. This problem occurs most commonly during the late fall through early spring and is promoted by wet weather or frequent irrigation.
Don’t overfertilize or overwater your lawn. Aerate your lawn once a year. At the first sign of the disease, apply a fungicide to the affected area.
There are two types of weeds, grassy and broadleaf. They are usually the result of poor turf, rather than being the cause of it. Weeds are aggressive and reproduce quickly, invading areas of thin, weak turf.
Keep plants healthy to help them outcompete weeds. Monitor and remove weeds regularly, before they go to seed. Do not bring soil with weed seeds or weed roots on-site. Use drip irrigation in beds so that you apply water only where you need it. Minimize foot traffic and pet activity in shady areas.
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