I'm going to try to improve on these efforts this year.
Yes, it's made of plastic. I wish this unit had a donut hole for compost, like the really expensive ones. It's self-watering, sort of. I lined it with newspaper and paper shreddings under the soil. Maybe this year it will become a tower of self-contained semi-invasive, prolific nutrition. The not-raised bed below did allow radicchio to self-sow a few plants ... but it has been cold. I may move them to the tower of power.
https://youtube.com/shorts/8B9AfLcBAQ8?feature=share