I have built 2 of these and they are amazing. I use one as my lettuce tower and the other for herbs and left over lettuce plants from my green house. For me it works well by keeping the plants off the grown and getting muddy or extremely dirty from hard rain. It also helps me save more produce from being eaten by rabbits.
Here is what it is:
The long tube running down the center of the vertical garden tower is a vermicomposting system. Half a cup of worms is added at the beginning of the growing season. Kitchen vegetable scraps are then added regularly to keep the vertical compost tube full.
The worms feed on the organic matter, turning it into worm manure called worm castings, an excellent organic fertilizer and soil amendment. As the worm castings accumulate and aerobic microbial digestion advances, the compost near the bottom of the compost tube turns to rich black organic matter and can be removed easily at the bottom of the tower.
What goes in:
Kitchen food scraps in
What comes out!
Compost out!
Here is a step-by-step video on how to make your own.
https://dtube.video/v/shadowblade/ty83d234
If you don't have the time or desire to make one I have seen I nice one on amazon.
https://www.amazon.com/dp/B01HXPPQO4/ref=asc_df_B01HXPPQO45136052/?tag=hyprod-20&creative=394997&creativeASIN=B01HXPPQO4&linkCode=df0&hvadid=216531775325&hvpos=1o2&hvnetw=g&hvrand=5519822231724917858&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9007414&hvtargid=pla-414662591037
Credits go out to http://www.gardentowerproject.com/generates-worm-activated-compost