Im a medical grower so I have the luxury of being able to grow legally, so along with my long time friend we are gonna have 24 plant garden this year. We dug all are holes about 3-4ft deep about 3'x3' area for each hole. Then we got 9yards of local soil that contains all your different fertilizers, we mixed it with ocean forest, promix, extra wormcastings, bonemeal, dolomite lime and quite a bit of perilite cause the main local soil has no perilite in it. To say the least back filling all 24holes that are that big is quite expensive, but in the end it is worth the money growing in good soil. Now if your going for a guerilla grow I doubt this all this work will be the right thing to do, but in my opinion the bigger the hole, the bigger the plant. We also have to line our holes with some wire that is similar to chicken wire but smaller because we do get problems with gophers. We'll probably be planting within the next 3weeks or so, Im in nor california, we have had the soil in the hole for a little over a week now. The plants wont need any feeding for probably 5-6weeks give or take, depending on when we start seeing signs from the leaves, but when we do start feeding we just use liquid gold and some fish emulsion during veg. When flowering comes around we'll have to decide on what line of nutes were going with this year, last year it was fox farm's 3 part powder nutesf, not sure if we'll go the same route this year or not. Thats just a basic overview, theres much more little things that come up, but if you have any questions I'll try my best to help you out, take care, peace.