Diagnose and fix
Why Your Lawn Has Brown Spots in Summer
By Patrick Klippen, Owner & CEOB.S. Landscape Horticulture · VDACS certified applicator #141054
Published Updated
Short answer
Most brown spots on a Northern Virginia lawn in July and August are heat and drought dormancy. The grass turns straw colored but stays rooted, and it greens up with water and cooler nights. Brown patch, grubs, compacted clay, and dog or mower damage cause the rest.
Match your symptom to the cause.
Check the shape of the brown area and whether the turf pulls up, then match what you see in the table below.
| Symptom | Likely cause | What to do |
|---|---|---|
| Uniform straw color, roots hold | Heat and drought dormancy | Water deeply and skip fertilizer |
| Circular tan patches in humid weather, worst in shade | Brown patch disease | Mow high, water at dawn, and use a fungicide if it spreads |
| Irregular dead areas after mid-July, turf lifts freely | Grubs | Count the larvae and treat if the count is heavy |
| Same spots brown first every year | Compacted clay or thin soil | Core aerate and overseed in fall |
| Small dead circles ringed with darker green | Dog urine | Flush with water and reseed in fall |
| Stripes with sharp edges along a spreader path | Fertilizer burn | Water heavily and reseed if the crowns died |
| Tan tips a day after mowing | Dull mower blade | Sharpen the blade |
Most brown lawns in a Virginia July are dormant.
Most brown lawns in a Virginia July are dormant, and the only treatment they need is water. Tall fescue stops growing when soil temperatures climb into the 80s, so the blades go straw colored, first on slopes, strips that face south, and thin soil. Give it an inch of water a week in one or two deep soakings until nights cool in September, and skip the fertilizer. The lawn care calendar has the rest of the season.
- Tug a handful of the brown grass, and if it holds, you're dealing with drought.
- If it lifts in a mat with no roots, check for grubs.
- Tan blade lesions with dark borders mean brown patch.
- Push a screwdriver into both the brown and green areas, and if the brown area is harder to push into, suspect compaction.
Brown patch shows up as circular tan patches in humid weather.
Brown patch is a fungal disease, and the one cause here that a fungicide fixes. It hits fescue in humid weather from late June through August as circular tan patches, worst in shade and dead air, as on the wooded lots around Reston. If a lawn gets it every year, a preventive fungicide costs less than a rescue treatment.
Grubs leave turf that lifts like loose carpet.
Grubs show up in late July and August as irregular dead areas that lift like loose carpet, because the larvae have chewed the roots off. Peel back a square foot at the edge of the damage, and treat only if you find about eight to ten white C-shaped grubs and the damage is spreading.
Compacted clay browns the same spots first every year.
If the same spots brown first every summer, the problem is compacted clay. Roots stay shallow and those spots dry out days before the rest of the lawn, especially along paths that get a lot of foot traffic, driveway strips, and builder topsoil that was stripped away, like on newer lots around Ashburn. The fix is a fall job, core aeration and overseeding, which is $279 flat for lots up to a quarter acre with us. If the soil is also worn out, compost topdressing adds organic matter to the clay and helps it hold water and nutrients.
Brown spots from dog urine, fertilizer, or the mower.
Dog urine, fertilizer burn, and a dull mower blade all leave brown spots, and the shape gives each one away. In newer subdivisions, buried mortar or gravel can brown the same spot every year, so dig before you treat it again. Our tall fescue care guide covers the habits that prevent the rest.
No. Nitrogen on heat stressed cool season grass forces growth it can't support and makes brown patch worse, so water deeply and save the feeding for September.
Usually two to three weeks with steady water and cooler nights. Fescue can sit dormant for weeks, but a long, total drought will kill it, and any tan patches that remain were a different problem.
Drought browning is uniform, fades into green, and hits sunny slopes first, while brown patch forms defined circles in shade and its blades show tan lesions with dark borders.
No, wait for fall. July and August soil temperatures kill seedlings before they root, and late August through October is the window here.
Related guides
Keep reading.
Lawn care fundamentals
Tall Fescue Lawn Care in Virginia
The grass most Northern Virginia lawns are made of, and the one yearly habit that keeps it from thinning.
Lawn care fundamentals
When to Aerate and Overseed in Northern Virginia
The fall window for core aeration and overseeding in Northern Virginia, and why earlier in it beats later.
Lawn care fundamentals
The Northern Virginia Lawn Care Calendar
What to do to a Northern Virginia lawn in every month of the year, and why fall matters more than spring.
