wow, what line are you running for under 10 bucks a grow?
Du
Prolly makes his own powder nutes
Of course that's going to depend on the grow size, but for me in flowering I use around half a gallon of feed per plant in a 4 sq/ft (2'x2') space, per day. If you have 4 plants in a 4x4 tent, that's 2-gallons of feed a day. If we do as
@Beehive suggested, and do the math, we can figure out how much it costs to feed a 4x4 tent during a full flowering cycle. As previously noted, you can make close to 4000 gallons of Jacks 321 for $100, so that would be $0.025/gallon, but let's round up and call it three cents a gallon. If you are feeding 2 gals a day, that means it costs you six cents a day for nutes. Let's assume a 70-day flowering cycle, with no flush; that would be $4.20 (convenient number) per grow per 4x4 space. Of course that doesn't account for the veg cycle, or any additional supplements that you might want to add, but you get the idea.