I hope everyone is well? I know that I am checking in way late with this but my wife wanted her patio finished. Anyway I have made yet another design using two rubbermaid tubs one 14 gallon and one 18 gallon. The 14 gallon tub sits into the 18 gallon tub. This is the easiest design yet and has the largest water reservoir and the same amount of potting mix as the other designs. I will have a PDF write-up on this in a few days. The head to head test will be four earthboxes one real one and three of my designs. The three designs are the earthbox copy, the dual tub mentioned above and the hybrid design with the aeration tubes instead of the screen. I will plant one sungold in each and we will see if one performs better that the others. Here are some pictures of the designs

The new dual tub design.

And the hybrid design.

Couple of queries:

A1 and B3 do not actually have "holes" into the inner tub? Only the center one goes all the way through?

How tall are those tubes? They look really big!

Wow I'm all-a-jingle that someone's actually trying a serious test on these!!! Yeee hah -- I have a vested interest having 11 tomato plants in pots as my land has almost no dirt between decks, patios, etc.

I am glad you are so excited about them. The pipes are 4 inch PVC drain pipe with some holes already drilled into it. They are just a hair under 7 inches tall (the distace from the bottom of the 14 gallon tub to the bottom of the 18 gallon tub). the pipe cost about 5 bucks for 10 feet at my local home depot here in the northeast. If you look close you will see that I drilled a diagonal series of holes in all three pipes. I have included a few more pictures that should give you some idea of the scale and my web site is listed at the bottom with the original DIY earthbox doc. Soon to be added to.

Thanks,
Joe