I am growing in soil, using a two part micro and bloom with bud candy. I feed at every watering. Once every 7-10 days. they are in 5 gallon buckets. It all depends on what stage you are in, how big they are, how sensitive they are etc. I have to adjust weekly on nute levels based on observations of what the leaves are telling me. Perky dark green leaves mean less N so I cut the micro down just a bit, if I see a few claw leaves I back off the micro totally and just feed bloom and bud candy. If they are getting any yellow at all, even a light green I increase the dose of micro back up to 8ML/gallon. The only way to truly know how much and how often to feed is to practice,practice,practice and observe lol. No one plant is the same, no one grower the same and all you can do is take advice and try different things.