Potatoes in a tall box -or- How to grow 100 lbs. of potatoes in 4 square feet
I've read but never tried this method of growing potatoes until now...
To get more potatoes - apparently way more - you essentially "stretch" the plant's root system out over the course of their growing cycle. And since the plants will produce potatoes wherever they have roots, more potatoes will result.
How do you "stretch" the plants? You keep burying the stalk, so that the buried portion puts out new roots.
The design I read about in my Irish Eyes seed catalog has this design: http://www.irisheyesgardenseeds.com/growers1.php .
You basically build a box and add 6" of height at a time by screwing in a new 6" wide board on . Each time you add a board, you add enough soil to bury the plants' stems by that amount, taking care not to bury more than 2/3 of the exposed stem.
By the time you are finished, the box should be 3 feet tall. Then, at that point, you start harvesting potatoes from the bottom first by removing the bottom-most board and culling the potatoes. You work your way up until you have harvested the whole plant, or plants. In this manner, you will get "new" potatoes, plus have plenty to store, if you can resist eating them all, come fall. All from the same plants. Pretty cool.
I am on the first board with my two boxes, this week.