I found a potato tower for limited space gardens .
It utilizes 4- 8 ft. 4x4's
which are used as the corner posts for the tower.
Sink them about 2 feet into the ground for stability, evenly space them about 4'4" apart in the shape of a square.
Next you will need: 20 - 6"x8' tounge and groove boards cut them into 4' lengths; These can be re-used Many times.
Mount the first 2 sets on the posts at soil level using screws for easy removal later.
(t & g is used to keep the soil from leaking out between layers as it would with regular boards.)
Fill the space with soil and plant your seed potatoes about 8 inches apart , attach another set of t & g boards and
cover with more soil.
wait, water-frugally, wait some more, Harvest after frost kills the plant tops.
As the plants grow (12" tall) add another set of the 6" t & g boards. Add soil to cover all but the top 6" of the plants.
Keep attaching new t & g every time the plant gets tall enough. The plants will be ready for more soil when they flower,
as that is when they are setting tubers.
Do this until you have attached all the t&g, should be 5 ft. tall.
As the season progresses near Harvest you can get an early taste of those "New Potatoes" by removing the BOTTOM
boards (this is why the screws) reach in and remove enough soil to get to the 'spuds'. Remove careful to not damage the
next layer up .
Replace the soil and the bottom boards, marking how high you removed the boards. This way next time you will know
which boards to start with.
According to the author you should be able to harvest 100 pounds of potatoes from this 4'w x4'l x 5'h planter.
Pretty good use of a small space IF you will be able to stay through Harvest. If you can't stay through Harvest
I would use tubs to plant in over a barrel just to be sure the plants get enough sunlight.