Best weather to spray vineyards
The weather window for spraying vineyards — Delta T, humidity, wind, inversion and rain — plus drift near homes, sensitivity of grapes and Custom settings.
Vineyards are sprayed often, mainly with fungicides, over a canopy that changes quickly through the season. Many are close to villages, homes and roads, and grapevines are themselves very sensitive to drift from some herbicides used in neighbouring crops. Drift control is therefore central to vineyard spraying.
The weather window
- Delta T: 2–8 °C. See Delta T.
- Humidity: avoid very dry afternoons, and wet foliage where the label advises against it. See humidity and dew point.
- Wind: a light, steady breeze, blowing away from homes and other sensitive areas. See wind speed for spraying.
- Inversion: valleys and hillsides often hold cold air and inversions at dawn and dusk. See thermal inversion.
- Rain: rain affects both product rainfastness and disease risk. See rain and spraying.
Crop-specific considerations
Homes and neighbours. Many countries set buffer zones or specific rules for spraying near homes, schools and gardens. Plan the order of rows around wind direction, spray the edges next to homes when the wind blows away from them, and follow the label and local regulations. See spray drift.
Sprayer type. Air-assisted sprayers are common; tunnel or recycling sprayers, which capture spray that passes through the canopy, can greatly reduce drift where available. Adjust air volume and nozzles to the size of the canopy, which changes a lot between early season and full leaf.
Grapes are sensitive to drift. Grapevines are known to be highly sensitive to some growth-regulator herbicides. Drift from nearby fields can injure them, which is also worth remembering if you spray other crops near vineyards.
Slopes and drones. On steep slopes, some countries allow spray drones or other aerial methods for vineyards. Check the rules — see agricultural drone rules by country — and the wind at flight height.
Disease timing. Many vineyard fungicides are applied before or after rain events, according to disease models and the label. The weather window between rains can be short, so check it hour by hour.
Typical applications
Fungicides (the majority), insecticides, herbicides under the vine rows, and foliar nutrients.
Setting it up in PulveCast
There is no vineyard preset, so use Custom. It starts from Delta T 2–8 °C, humidity 55–95 % and a Medium droplet class. Conservative starting points:
- Keep Delta T at 2–8 °C.
- Set the droplet class to what your sprayer produces, or leave it on automatic.
- Lower the maximum wind from the 25 km/h default towards 15 km/h (about 9 mph), or to the label's or local rules' limit.
- Keep the thermal inversion threshold at the 1.5 °C default.
Other crops
- Best weather to spray soybeans
- Best weather to spray corn (maize)
- Best weather to spray sugarcane
- Best weather to spray cotton
- Best weather to spray wheat
- Best weather to spray coffee
- Best weather to spray rice
- Best weather to spray citrus
- Best weather to spray potatoes
- Best weather to spray pastures
Frequently asked questions
How do I reduce spray drift in a vineyard near homes?
Spray when the wind blows away from homes, use drift-reducing equipment such as tunnel sprayers or suitable nozzles where available, adjust air volume to the canopy, avoid inversions, and follow the buffer zones in the label and local rules.
Are grapevines sensitive to herbicide drift?
Yes. Grapevines are known to be highly sensitive to some growth-regulator herbicides, so drift from nearby fields can cause injury. Operators spraying near vineyards should take particular care.