Quite frankly, since I wrote that guide I no longer really use any foliar sprays except when needed; such as for pest control and mold prevention etc......I just don't really like what it does to the leaves after awhile. That said; if I was still using one it would be Liquid Light by Dutchmaster. Expensive, but DM products work well. I'd save the $$ on foliar sprays and let the nutes and light do the work.