Quote Originally Posted by Dimebag
cannabis eats up epsom salts like theyre a once in a life time find. Dont worry about Ph too much if you dont over feed. since magnesium and sulfer are secondary nutes, you should give them half of your primary nutes. for example... if you feed your plants 1 tsp of 20-20-20 (primary) per gallon, then you should feed 1/2 tsp of epsom salt (seconday) per gallon. If you over feed them with salts, then your weed may face nutrient lock-out. Does this help?
I've was giving them a reasonable squirt of liquid feed I got from the local growshop twice a week but then they started to yellow so I cut it back. I realise now that they were pot-bound and not just being overfed. I've stepped up the feed to about 2 tablespoons of feed (between three plants) every day/every other day and they're taking off! I just get the feeling that, if there's nothing in the pot except roots, they're probably a bit short of everything. I'll pop some Epsom salts in a couple of times a week.

Thanks very much