I saw a structure built out of wood at the Chicago Botanical Gardens in the small garden section that basically was a wood frame say 6' high x
5' wide x 1' deep. It had landscape fabric on the front (I assume the back was solid) and had the plants poking out through holes cut in the fabric. You can grow herbs, vegetables or flowers. Basically, you are getting 30 Sq Ft of gardening space in a 5 SQ Ft footprint. Obviously, you probably couldn't grow watermelons or something like that (possibly on the bottom) , but I think most things would work.
My question is has anyone built something similar and how did you do it? My concern is keeping the dirt in and adding dirt through the small holes cut in the landscape fabric. Maybe they are able to add dirt from the top or the back?? Any ideas/suggestions are welcome. I need to get over there when it warms up to get a closer look at how they built theirs.