Auxin sprays over the top of pre-stuck cuttings is an alternative to dipping auxin treatments.
Aqueous auxin between 500 and 2000 ppm are sprayed on the leaves until runoff usually using a backpack sprayer.
Spraying auxin requires less labor and can reduce workers to auxin exposure.
However, it requires more auxin to treat cuttings with a spray that can offset cost savings in labor.
Auxin spray application.
The spray method uses an atomizer to spray the foliage.
Timing – until the solution drips from the leaves.
Concentration – 500 to 5,000 ppm.
Solution type – usually the potassium salt of IBA in water.
Effectiveness – varies by species, but when effective it reduces worker exposure and labor time.
K-IBA is prepared in a water solution for spray applications.