Me too, foliar feeding is great.I do it all the time. Mostly with actively aerated compost tea, but also humic/fulvic acid and micro-nutrients sometimes. I don't know about these issues people are talking about... besides increase chance of mold (only one I can think of), which usually only becomes an issue during bloom. Best time to foliar feed (esp. during bloom) is just before\shortly after lights on. You should not spray anything too soon before the lights go off, or in most cases during the final weeks of bloom.