Just wanted to know can I use regular soil out of the ground instead of some you buy in a bag (potting mix). If I can use regular soil, what should I look out for when trying to find some good soil? There are some farms where I live that have just been ploughed, would the soil in these fields be any good? I'm doing an outdoor grow and I want to see if I can grow weed without having to buy anything what so ever. Apart from buying the seeds obviously Thanks.