Last summer, we had a sudden hot spell just as my baby onions were getting started. The delicate shoots were fried beyond any hope of recovery.
As I was pondering what to put in the now-vacant 2 foot by 4 foot space in the planter box, I came across a few potatoes lurking in the back of the bin that were more sprout than potato. Just the thing. I cut them into chunks, being careful not to disturb the sprouts, and laid them gently in the area vacated by the onions. Then I covered them with a heavy layer of compost and left them to their own devices.
I soon had an impressive display of green potato plants. My only clue to what was going on underneath was an occasional glimpse of a tiny potato poking above the surface. I just added more soil whenever the baby potatoes became visible, and otherwise ignored them.
A couple of days ago, I took advantage of a break in the rain to check out the garden. The potato plants looked to be mostly dead, and were turning to slime in the rain. Although the gardening books tell you you can just store potatoes in the ground, I figured that wasn't a good idea in our wet climate. So I dug them up and brought them indoors. I gathered about eight pounds of potatoes, ranging in size from little marbles to about four inches long. Not a huge crop maybe, but not a bad return on a handful of potatoes that were destined for the compost heap.