i would recommend you put your plants in containers. This is what i did: I bought 4 inch drainage ducting (plastic tubing about $1 a foot) i cut the ducting into 1 foot lengths and wrapped the bottom in burlap for drainage. Filled the tubes with dirt nearly to the top. I veg them in these outdoors until the roots are busting out the bottoms. THen i trim the roots for a few weeks so the rootball goes nuts. I have a theory that the plants dont need wide containers for the upper portion of their roots. They seem to ball out at when they get a little larger. Once they are vegged ill put the tubing on top of 5 gallon bags so they have plenty of vertical room to grow down into and room to grow out. (if your going to dig holes its a bitch and you cant move your plants. You will want to dig holes at least two to three feet deep and put in good soil) By doing a pyramid style i save on soil, and when i water the plants from the top of the tube the water runs straight down the roots ensuring they get plenty of nutes with minimum watering. Also i tape the top of the tubing with copper tape. its expensive so the 4 inch tubing isnt too bad. The tubing is also ribbed so it holds the soil well.