Spraying is the most routine job on many farms and the one most likely to cause harm. The chemicals are designed to be biologically active, and the operator stands closer to them than anyone. Most exposure happens not during spraying but while mixing, and most of it lands on the hands.
None of what follows is complicated. It is a set of habits.
Protective equipment
The minimum for any pesticide application:
- Chemical-resistant gloves — nitrile, not cotton or leather, which absorb and hold chemical against the skin. Wear them for mixing, not just spraying.
- Long sleeves and long trousers, or a coverall. Cover skin completely.
- Boots, with trouser legs outside the boot so spray runs off rather than in.
- Eye protection — goggles that seal, not open-sided safety glasses.
- A respirator suited to the product. A cloth mask does nothing against vapour. Read the label for the type required.
- A hat or head cover, particularly when spraying upwards into a canopy.
Wash the gear after every use and wash it separately from household clothes. Replace gloves as soon as they are torn or sticky.
Mixing is the dangerous part
Mixing means handling concentrate. Do it outdoors, upwind, with gloves and eye protection on, and never with bare hands. Use a dedicated measuring jug that is never used for anything else. Add chemical to water, not water to chemical. Rinse the empty container three times into the tank so nothing is wasted and nothing is left in the container.
Never eat, drink or smoke while handling chemical, and wash your hands before you do any of those things afterwards.
When to spray
Early morning or late evening. Midday heat evaporates droplets before they reach the leaf and increases vapour that the operator then breathes. Cooler hours also mean less thermal updraft carrying spray away.
Calm conditions. Light, steady air is ideal. Still, dead air is not actually better — it can hold fine droplets in suspension. Strong wind causes drift onto neighbouring fields and onto you. If leaves are moving noticeably, stop.
Not before rain. Check the forecast. Rain within a few hours of application washes the product off and you will have paid for a spray that did nothing.
Spray with the wind at your back and work so you are never walking into what you have just sprayed.
Dosage: more is not better
Over-dosing wastes money, damages crops, speeds up pest resistance and leaves residue that can fail testing. Under-dosing fails to control the pest and also encourages resistance.
Read the label for the product you are using and follow the dose it specifies for your crop. Calibrate the sprayer so you know how much liquid you actually apply per acre, rather than estimating. A worn nozzle quietly applies far more than you intend — see our guide on nozzles and spray patterns for how to check output.
After spraying
- Wash hands, face and any exposed skin thoroughly before removing your mask.
- Change out of work clothes and wash them separately.
- Flush the sprayer with clean water and dispose of the rinse safely, away from wells, canals and drains.
- Observe the re-entry interval on the label before anyone goes back into the treated area, and the pre-harvest interval before harvesting.
- Store chemicals locked, in their original labelled containers, away from food, feed and children.
If something goes wrong
Skin contact: wash with plenty of soap and water immediately. Eyes: rinse with clean running water for at least fifteen minutes with the eye held open. In either case, and in any case of feeling unwell, seek medical help and take the product label or container with you — the label tells the doctor what they are treating.
Equipment matters too
A leaking sprayer soaks the operator's back all day. Check the tank, seals and hose before each use, and repair leaks before spraying rather than after. Choosing the right machine helps as well: a well-matched sprayer finishes the job faster and cuts exposure time. See the spray pump range, or our comparison of battery sprayers for lighter work.