I follow old world garden farm, (their website has information on it as well as raised row gardens..and just had my boys make some straw bale size crates.. I have dirt in the bottom, add my taters or slips, then as they grow keep adding a mix of dirt, compost and straw until full and harvest. I'm still learning and need to do better with composting (it takes too long and I always get behind on that then don't have enough, but I currently have 2 piles started, so hopefully this year I'll do better with it) I tried winter sowing method too, and got some of my onions in the ground today.