This is where foliar feeding gets tricky & dangerous,you can foliar feed the buds but caution must be used,other than the obvious risk of nute burn directly to the bud you can seriously slow bud production should even the slightest bit of nute burn take place,i'd mix it at an ultra weak strength like less than 1/4 strength.
Also wet buds are not good,depending on bud thickness & air circulation the foliar spray can cause budd rott,i do foliar feed my buds once about a month into the bud cycle & what i do is after feeding them i let the foliar fertilizer dry completely then re mist with plain water ,this extra misting with clean water rinses off any excess nutrient salts that were not absorbed by the bud so a topical burn can taker place,i only foliar feed one time though as i want to be sure that any nutrient salts are 100% used before harvest.
After allowing enough time for the clean water rinse to air dry you should have a fan blowing a steady stream of air directly on the buds,this ensures that no moisture is trapped in the budd & gaurds against the nasty ass bud rott mold.
