If going this route. Grow pure sativa's. Certain ones don't require much nutrients. Some indica are like pumpkins the way they feed. Try to avoid those strains and you should do well with minimal nutrients. If you want cheap/free. Start a compost and worm bin. If you are lucky Black Soldier fly's will show up to the party and you can collect the old casings for frass. They will also process food scraps 3-5 times faster than compost worms. They are awesome they showed up two years in a row to my worm bin. If you have a lizard or chickens, you got some free feed for them.