I'm assuming you mean 3'w x 3'L. What's the height? I'd suggest at least 5 foot if you want to have plenty of room for the plant to grow without running into the lights.,fan, or other stuff you have in the grow box. You can get by with less, but you aren't going to be able to veg your plants very long before flowering without them getting 3 ft+ by harvest time. Also, the nutes your using are all right for vegging, but your going to want to get something else for flowering. During flowering you want the ratio of N to P to be closer to 1 - 2 because the plants need more P for bud production and less N for leaf and steam growth. Jacks classic all purpose and bloom booster are supposed to be a good full life cycle fertilizer set (I'm still using fox farm, but plan to try Jacks on my next grow), and you can pick both of them up for about $15 total.
