Foliar Feeding with the lights on is like burning ants under a magnifying glass. When the light hits the water, it is like going through a magnifying glass burning your plants; making you think that the plants are sick or diseased. In some cases with good wetting agents you can completely burn your plants to a crisp. Your plants must be dry when the light comes on or you WILL burn them. Burning the plants while foliar feeding will make the plants more likely to get sick.