What you see: A papery, dried stem-y bit attached to your potato
What it is: The remnants of a stem that should have fallen off
Eat or toss: Pinch or cut it off and eat! This is harmless.
Why is it OK to eat potatoes with stems?
The first word of the day is abscission, otherwise known as the natural and deliberate separation of two parts of a living thing.
It happens when flowers drop petals, when trees lose leaves, or when fruit falls to the ground. It even happens when certain reptiles allow their tails to detach to evade a predator.
And it should have happened to this potato. But alas, something misfired.
So, this brings us to our second word of the day: stolon. A stolon is an underground stem. Potatoes develop from stolons. If all goes to the potato’s plan, once the growing season ends and temperatures get colder, the stolon will eventually abscise from the potato, leaving the tuber all on its own underground. Then, when the time is right, the potato will produce sprouts, which will use nutrients from the potato to climb above the soil and grow into above-ground leafy green plants that can be taller than a fire hydrant. Eventually, those plants will send out their own underground stolons, from which more potatoes will develop. Check out this great visual of the process from the International Potato Center.
Normally, the connection point between the stolon and the potato, aka the abscission zone, will dry out once the potato is mature, leading to an easy separation. But there are a number of reasons why it might not detach, explained Nora Olsen, potato specialist for the University of Idaho. It could have been harvested too early, when the stolon was still green; it could have been a quirk of the particular growing season; or it could be a variety like Alpine Russet, which generally struggles with abscission zones.
“There’s no concern eating it,” Olsen said. “If I had those I would just physically pluck them off. Or, if they don’t easily come off, I would cut them off because they would look unsightly if you put them in your meal.”
And, just to get it out of the way—this stolon is not a sprout. You want to be a little careful with sprouts because they can pack higher concentrations of the potato’s defensive toxins (more in this post about sprouts and this one about green potatoes). According to Olsen, the stolons are unlikely to have problematic toxin levels.
- Nora Olsen. Professor and potato specialist, University of Idaho.
- How Potato Grows. International Potato Center (CIP).
- Abscission in plants. Vilde Olsson and Melinka A. Butenko. Current Biology. Volume 28, Issue 8. April 23, 2018.
- Stolon. Encyclopaedia Britannica.
- Recent developments in abscission: shedding light on the shedding process. Zinnia H. Gonzalez-Carranza, Edmundo Lozoya-Gloria, Jeremy A. Roberts. Trends in Plant Science. Volume 3. Issue 1. January 1, 1998.
- Effects of Foliar Boron Fertilization on Tuber Stolon Retention in Alpine Russet Potatoes. Carl Rosen, James Crants, and Matt McNearney Department of Soil, Water, and Climate, University of Minnesota. Included in the 2018 Research Reports by the Minnesota Area II Potato Research and Promotion Council and the Northern Plains Potato Growers Associate.
Fun fact: Back in the 19th century, when gas lamps lit up city streets, trees near said lamps found themselves dropping more leaves. Why? Because ethylene, released by plants to prompt ripening, abscission and other things, is also found in exhaust, like the kind you get from gas lamps. Quite the indignity when you consider that the lamps both made those 19th century trees a bit more naked and put them in the spotlight all at once!