What's wrong with your lawn?
Drop a photo of the bad patch. You get the likely cause, how urgent it is, and treatments that are safe for your grass type.
- Diseases: brown patch, dollar spot, rust
- Pests: grubs, chinch bugs, armyworms
- Weeds: crabgrass, nutsedge, clover
- Nutrient deficiencies: nitrogen, iron
- Environmental stress: drought, compaction, dog spots
Reviewed by James Thornton · Lawn Equipment & Maintenance Expert · 20 Years · July 5, 2026
Disease, pest, and weed candidates filtered by USDA region and current season; treatments cross-checked against grass-type herbicide safety data
How the lawn diagnosis works
- 1
Photograph the problem area
Fill the frame with the damaged patch in daylight, including the edge where bad grass meets good — the transition pattern is often the most diagnostic feature.
- 2
Add your ZIP code
Diseases, pests, and weeds are regional and seasonal. Your ZIP narrows the candidate list to problems actually active in your area right now.
- 3
Get a ranked diagnosis
Each problem found comes with a confidence score, severity, urgency, and the visual evidence behind it — plus immediate actions and treatments that are safe for your grass type.
Diagnose lawn problems by symptom
Match what you see to the most likely cause. A photo scan confirms it: many of these look alike, and the treatment for one can make another worse.
| What you see | Most likely cause | First move |
|---|---|---|
| Large irregular brown patches, smoke-ring edge on humid mornings | Brown patch fungus (hot, humid nights + wet leaves) | Stop evening watering; water pre-dawn; hold off on nitrogen |
| Many small straw spots, silver-dollar to baseball size | Dollar spot (often underfed turf) | Water deep and infrequent; a light nitrogen feed if the lawn is hungry |
| Brown areas that peel up like loose carpet | White grubs eating the roots | Tug test a patch edge; count grubs per sq ft before treating |
| Expanding yellow-to-brown patches in full sun during hot, dry spells | Chinch bugs (especially St. Augustine) | Float test: press a bottomless can into the edge, fill with water, watch for bugs |
| Orange-red dust on blades that rubs off on shoes | Rust fungus (slow-growing, underfed turf in late summer) | Feed lightly, mow more often, and bag clippings until it clears |
| Even yellowing that starts on older, lower leaves | Nitrogen deficiency | Apply a balanced fertilizer at label rate |
| Yellow newest leaves with veins still green | Iron chlorosis (common on high-pH soil) | Chelated iron now; soil test to confirm pH before bigger changes |
| Dark green rings or spots with dead centers where a dog goes | Dog urine burn (concentrated nitrogen and salts) | Rinse fresh spots; rake out dead turf and reseed or plug |
| Grass wilts, looks blue-gray, and footprints stay visible | Drought stress | Water deeply (about 1 inch per week including rain), early morning |
Brown patch or dollar spot? The two most confused diseases
Both leave straw-colored patches, but size and pattern separate them. Brown patch makes large irregular areas from one to several feet across, often with a darker smoke ring at the edge on humid mornings. Dollar spot makes many small, sunken, silver-dollar-to-baseball-sized spots that can merge, with hourglass-shaped lesions banding individual blades. It matters because brown patch is driven by excess nitrogen and night watering, while dollar spot often shows up on underfed lawns: the wrong guess feeds one disease while treating the other. A photo scan weighs both against your region and season.
Treatment safety depends on your grass type: several common herbicides that are fine on bermuda will damage St. Augustine or centipede. Not sure what you have? Identify your grass type first.
Not sure which one matches? A photo scan ranks them for your lawn.
Lawn diagnosis FAQ
What lawn problems can the diagnosis tool identify?
The AI checks your photo against five problem classes: fungal and bacterial diseases (brown patch, dollar spot, rust, snow mold), insect pests (grubs, chinch bugs, armyworms), weeds (crabgrass, nutsedge, broadleaf invaders), nutrient deficiencies (nitrogen, iron), and environmental stress (drought, compaction, dog spots, scalping). Each finding comes with a confidence score, severity, and urgency rating.
How accurate is the AI lawn diagnosis?
Accuracy depends heavily on photo quality and how visually distinctive the problem is. The tool reports a confidence score with every finding and filters candidates by your region and the current season, so a cool-season disease will not be suggested in a hot Texas July. Diagnose is in beta: for expensive treatment decisions, confirm with your local extension office before buying products.
Why do you ask for my ZIP code?
Diseases, pests, and weeds are regional and seasonal. Your ZIP code lets the AI narrow the candidate list to problems actually active in your area right now, which significantly improves accuracy and keeps irrelevant problems out of your results.
What photo works best for a diagnosis?
Fill the frame with the problem area in bright, even daylight. Include the transition zone where damaged grass meets healthy grass — the edge pattern is often the most diagnostic feature. For suspected insect damage, a close-up of the soil line helps. Avoid shadows, dew glare, and photos taken from standing height.
Do I get treatment recommendations?
Yes. Each diagnosis includes immediate actions ranked by urgency, prevention tips, and treatment recommendations covering cultural practices, organic alternatives, and chemical products. Chemical suggestions are cross-checked against your grass type so you are never pointed at a herbicide that would damage your lawn.
Is the lawn diagnosis tool free?
You get free analyses each month — diagnoses and grass identifications share the same allowance. Creating a free account raises the monthly limit, and Premium removes it entirely along with saved history and smart reminders.