Nice way to grow a lot in a small space. I like the idea if I could find used barrels. I think it would be great for strawberries.
One barrel would probably be a great way to grow salad greens all in one.
Easiest earth explains how its done.

3-D Vertical Barrel Gardening – A Striking Use For Used Barrels
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Round Ceramic Strawberry Jar with 6 Pockets Color – Aqua Green