Wind Speed

Wind is the most common reason a spray gets rescheduled, and the reason is not the one most people assume.

Three to seven miles an hour is close to ideal. Under ten is workable. Over ten and we stop, because above that the droplets stop landing where they were aimed and start landing somewhere else.

And dead calm is not the best case. It is often the worst — which takes some explaining.

  • When the wind picks up to a moderate 5-10 mph, our spraying operations become a bit more challenging. While it's still possible to spray under these conditions, it becomes questionable. We take extra precautions during these moments, carefully assessing the wind's direction and speed to ensure the safety and effectiveness of our treatments. At this wind speed range, there is a higher potential for spray drift, which can carry chemicals off target. We prioritize responsible application practices to minimize any environmental impact. We proceed with a cautious eye on the wind, striving to strike the right balance between your landscape's needs and the conditions we work in.

  • Little or no wind at the time of application — and not automatically the ideal condition it sounds like.

    Still air often means a temperature inversion: a layer of cool air trapped beneath warmer air, with no vertical mixing. In an inversion, spray droplets do not disperse and settle. They hang as a concentrated cloud and drift sideways, slowly, a long way. A still morning can carry an application further off target than a light breeze will.

    Inversions typically set in around dusk and break up after sunrise. It is one of the reasons a crew may arrive and wait before starting.

    More on this: wind speed and spray drift.

  • When the wind exceeds 10 mph, our spraying operations become less favorable. We prefer not to spray under these windy conditions. Strong winds can significantly compromise the precision of our treatments and pose potential risks to the environment. At this wind speed, there is a heightened risk of spray drift, which may carry chemicals beyond their intended target areas. We prioritize safety and environmental responsibility above all else. During windy days, we may choose to postpone our spraying activities, ensuring that your landscape receives the meticulous care it deserves under more suitable conditions. Your satisfaction and the well-being of your surroundings are always our top priorities, and we take great care to act in harmony with nature's rhythms.

Why still air is a warning, not an ideal

When there is no wind at all, it frequently means a temperature inversion — a layer of cool air trapped beneath warmer air above it, with no vertical mixing happening.

In an inversion, spray droplets do not disperse and settle. They hang as a concentrated cloud and then move sideways, slowly, a long way, wherever that layer of air goes. A still evening can carry an application further off target than a breezy afternoon will.

Inversions usually set in around dusk and break up after sunrise, once the ground warms and the air starts moving vertically again. Which is why a crew that arrives at seven and waits an hour is not wasting your time — they are waiting for the air to start mixing.

What else we control

Wind is not the only variable. Nozzle choice changes droplet size, and larger droplets fall faster and drift less. Wand and boom height matter — the higher the spray starts, the further it can travel before it lands. Those are decisions made on site, based on that morning's conditions.

Why it is on your paperwork

Every application records the wind speed at the time. That record is how we show the work was done under conditions the product label allows — and when we tell you we could not spray today, it means there is a number behind the decision rather than an opinion.

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