Garden Disease Risk by Location or Zip
See how typical growing-season weather favors common disease groups near you. Switch tabs for late blight and downy mildew, powdery mildew, or early blight and leaf spot.
Choose a disease group
Disease Risk forLate blightLate blight & downy mildew
Find your disease risk severity by location
Enter a ZIP code or use your current location to explore relative disease risk severity on the map.
What diseases are these?
Water-mold (oomycete) diseases that thrive when leaves stay cool and wet for long stretches.
- Late blight on tomato
- Downy mildew on cucumber, cabbage, lettuce, onion, peas, radish, and spinach
What plants can resist these diseases?
On seed packets and plant tags, look for resistance that maps to this disease group—not generic “mildew” alone.
- Tomato: late blight resistance is often labeled LB, Ph, or Phytophthora infestans (sometimes Ph-2 / Ph-3).
- Cucumber, squash, melon: downy mildew is usually DM or P. cubensis—not the same as powdery mildew (PM).
- Lettuce, spinach, onion, brassicas, peas: look for “downy mildew resistant” or a cultivar known for DM resistance in that crop.
What type of climate influences risk?
This map ranks places by how often typical growing-season weather is both cool and persistently wet—the combination that favors late blight and downy mildews.
- Cool temperatures (roughly the mid-teens °C / upper 50s–60s °F during wet periods) score highest; very hot or cold days score low.
- Long leaf-wetness / high moisture hours raise risk; dry days contribute little.
Disease Risk FAQs
Disease Risk describes how often typical growing-season weather favors groups of common garden diseases—not whether a disease is already present on your plants.
Scores compare climate pressure across the mapped region: low, moderate, or severe relative to other places.
Each tab focuses on a disease group that thrives under a different mix of temperature and moisture.
We built it so you can know your climate’s predisposition to common disease groups and make better choices before you start gardening—not only once plants are already under pressure.
Maps show how often typical growing-season weather favors late blight and downy mildew, powdery mildew, or early blight and leaf spot near you, relative to other places.
Use that up front: choose resistant varieties where pressure runs higher, prioritize crops that struggle less under local climate favorability, plan spacing, airflow, and watering habits for the groups that matter most, and match plant shortlists to local pressure.
Diagnosing a sick plant or identifying a pathogen from a photo.
Day-to-day spray timing or replacing local extension recommendations.
They are relative tertiles across the mapped region: each band covers about one-third of places, ranked by growing-season disease-favorability climate—not absolute outbreak odds.
Severe means that location ranks in the higher third of the map for that disease group’s climate pattern; Moderate the middle third; Low the lower third.
Cutoffs come from the score distribution across the mapped region, so bands compare places to each other rather than fixed absolute favorability thresholds.
Different diseases thrive under different weather. One tab covers late blight and downy mildew; another covers powdery mildew; the third covers early blight and leaf-spot style diseases.
Switch tabs to see how pressure for each disease group compares at your location.
No. Favorability means how often typical growing-season weather favors a disease group’s climate needs—multi-year normals, not a live forecast that disease will appear on your plants.
Climate scoring is inspired by classical open disease-forecast models (for example BLITECAST-style temperature and moisture logic for cool-wet diseases), loosely adapted for grid climate normals rather than identical day-to-day operational forecasts.
Enter a ZIP code or use your current location, then choose a disease group tab.
Pan the map so the center reticle sits on your garden—the severity readout updates for that point.