Foliar feeding is an effective way of providing fertilizer to your plants.
But if soil pH is within the optimal range and the roots are healthy, it may not be necessary.
In fact, spraying anything on a crop increases the chance of foliar disease and leaf damage.
A light spray will likely evaporate from the leaf surface within 30 minutes, but if water becomes sandwiched between leaves or trapped within the canopy, omnipresent mold spores can begin to germinate.
Spraying a crop increases the chances of leaf burn as well. If the nutrient solution is improperly mixed or applied during “lights on” or under full sun, leaf damage can occur.
Only if a plant cannot consume nutrients due to a compromised root system does foliar feeding makes sense. Otherwise, play it safe and let the roots do their job.