if you want them all to be same quality, and not have some plants steal from the others, just make separators within the bed... the major pain in the ass with a bed of soil, is movement... getting it in and out of the grow space is a bitch in a half. highly not advisable if you dont have enough room in the grow area to tend to plants within, without having to move them. but hell if you got the space, and don't have to move it except at harvest, go for it... just buy a huge rubbermaid, get some peices of plastic, a heat pen (cheap as hell) plug it in, make however many separator welds drill some holes for drainage, dump in soil and bam...