1 · Droplet size — the biggest lever
Small droplets hang in the air and blow away; large droplets fall fast and stay put — but you still need enough coverage to work. Pick a category and watch the drift-risk meter and droplet picture respond.
Categories follow the ASABE S572 droplet-size spectrum used on pesticide labels. Many labels specify a minimum droplet size — that's a legal requirement, not a suggestion.
2 · Temperature inversions — the invisible trap
On calm evenings the air near the ground can turn colder than the air above it. That "inversion" traps fine droplets in a stable layer that can slide sideways for miles. Toggle the conditions:
3 · Wind & buffer zones
Most labels allow application in a wind range (often ~3–10 mph) and require a downwind buffer near sensitive areas. As wind rises, a safe buffer grows. Slide to see the idea:
Pre-flight drift checklist
- ☐ Read the label's droplet-size and buffer requirements first.
- ☐ Measure wind at the site — speed and direction. Note what's downwind.
- ☐ Never spray into a temperature inversion (calm, cool, smoke/dust hangs flat).
- ☐ Choose the coarsest droplet that still gives label-required coverage.
- ☐ Set the flight height low and consistent — higher release = more drift.
- ☐ Keep the required buffer to water, homes, hives, and sensitive crops.
- ☐ Record conditions (wind, temp, time) for every job.
Guidance reflects standard extension and label-based drift-reduction practice; droplet categories follow ASABE S572. Buffer numbers here are illustrative — always use the specific product label and your state's rules.
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