Pretty clever. Are those barrels cut in half?
Duke! Questions here (Post 76) about your greenhouse planters!
Yep. We had four of them we picked up somewhere. I checked the bottoms to see that they were food grade, and then cut them along their seam line with my cordless circular saw. Washed them out and then attached them to the upper 2 by 4 framework. Three 2 by 4s just longer than the distance from top to bottom and two to connect them. Then add four legs (I cut them 30” long so that I could fit them through the greenhouse door and added some bracing below. I finished them up with a length of plastic gutter under each half barrel. I will be drilling drain holes along bottom so this will help localize water.
To finish this up, I am going to attach plastic gutter along the back to collect the drainage and route it to one location. I am also thinking about a storage shelf under each set of half barrels, possibly on small wheels to make access easier.
Hope this helps.