So I've done pretty good cloning but feel there is room to improve, i have had clones take anywhere from 4 days to 3 weeks to develop roots, some of them clone way easier than others, (depending on strains) sometimes they are almost to the brink of death before they develop roots with dying and yellowing leaves and have to be nursed back and to me they seem starved, so my question is should i be feeding clones through foliage and if so what ?