Pulling up some volunteer potatoes, growing in close and competitive with some winter squash, I was mildly startled by this bright white activity among the roots. They’re the runners that head out to find a little clear spot to form new tubers—really new new potatoes. Can’t recall seeing them before, probably because this is the first time potatoes have turned up as weeds.
Of course, there is an explainer story. The runners, called stolons, are actually underground stems, totally apart from the roots. Along with the tiny tubers, they’re practically pure potato starch, creating storage for what is the plant’s fuel, and continuation of the plant’s life. The little pod tubers already have eyes, but they stay tiny and invisible to us. The tubers keep growing until they hit their genetic max size, or the leaves start dying off and there’s less starch. Then they form a protective skin to preserve the eyes and starch and wait out winter. When conditions feel right, the eyes start to grow, and eventually sprout into new plants.
If you put the stolons and baby tubers above ground in the light, they’d soon start turning into regular stems, stop storing and start using their starch, and try to push out leaves. I’ll trust the textbooks on this, don’t feel the need to see for myself at the moment…
So really, planting seed potatoes, not actual seed, means it’s all one continuous potato, year after year, as long as you keep planting some of its tubers. It’s vegetative propagation—just like garlic, but with a lot more to see. Pretty cool!