I read up on this a few years ago and decided to make my own and seeing as there are no instructables on it I had to make one!
I have a really big gopher issue and them eating my tree roots and any flowers or vegetables I plant. this set up doesn't "eliminate" the pests but it doesn't feed the. now either. Also it will be easier to maintain as there are little to no weeds to pull and sitting on your knees to plant, fertilize, and harvest is nice since everything is at chest level and you don't have to bend over. plus you can sit on them and work if you like too!
Step 1: Choosing a bale type and amount
your will need to choose bales that are easy enough to move around and place into a permanent position as once they get wet they will be near impossible move. As well as bales that contain little to no weed or bale seeds. this will cut down on weeding. lastly how many bales you will need. depending on your space its safe to say you can get 2 large plants (squash,cucumber, etc) 4-5 medium plants (peppers,beans,etc) or 2 rows of plants (carrots, corn, radishes, etc) so you will need to have an idea of what you want to plant and how much of it you plan to plant then just like any in ground garden just space them out as you like.
good bale choices are:
1-straw...has no weeds in it , light weight, about $8-12
2- grass/pasture mix...dense, some grass weeds,about $2-8
3- oats....some oat seed in it but not bad, about $8-12
4-wheat...has some seeds but easily stopped early on. about $8-15
5- alfalfa...DO NOT USE!!! HIGH SEED COUNT OF BOTH WEED AND ALFALFA. NOT RECOMMENDED! about $10-16