Foliar feeding helped me when I had nutrient lockout due to severe soil acidification (due to salt build up, due to over feeding). If you do it, you should protect the plants from strong light because the droplets act like lenses causing light burn. If you were in flower you'd also have to weigh the risk of bud rot. Use about 1/4 strength and ph 6.5.
I've read your various questions for this grow. Your perseverance is admirable. But, growing weed isn't this hard. You'll continue to learn from this grow. But, I think it is more expedient (and you'll be happier) to abort and start a new one.
Whenever you start a new grow, start a journal where everything you do is documented. I don't think you're getting the help you should because your questions arise piecemeal, and we have to ask you to remind us what you've done so far.