Applying Plant Growth Regulators: Five Mistakes to Avoid

Plant growth regulators can affect crop development at low application rates, and an unsuitable use may damage plants or create compliance and residue concerns. Avoid these five common mistakes and use product-specific directions as the primary guide.

1. Assuming a higher rate gives a better result

Do not increase or reduce a rate based on a general recommendation or another crop’s experience. Use only the rate and application method specified for the product, crop and market.

2. Applying to the wrong crop or growth stage

A product may be authorized for only certain crops, uses or stages. Confirm the current label before application; do not extrapolate from a related crop or from a similar active ingredient.

3. Mixing products without checking compatibility

Tank mixing can change product performance or create crop injury. Mix products only when the label and local rules permit it, and follow the required sequence and precautions. A small physical compatibility test does not establish that a mixture is legally permitted or safe for the crop.

4. Ignoring weather and greenhouse conditions

Temperature, light, humidity, leaf wetness and crop stress can affect application performance. Follow any product-specific limits and avoid making up universal temperature or humidity cutoffs. Check the crop and greenhouse conditions before proceeding.

5. Skipping records and safety steps

Record the product, rate, crop, date, application area and relevant conditions. Follow required protective equipment, re-entry intervals, pre-harvest intervals, storage and disposal instructions. These requirements vary by product and market.

Before every application, check the current local label and confirm the intended crop and use are authorized. When in doubt, pause and consult the product registrant or a qualified local crop adviser.