I don’t think you’re supposed to grow potatoes in a self-watering box. I tried it anyway, and they’re growing very well, with a really healthy-looking green color.
They actually grow so well that they can’t support their own weight and fall over. The exact same thing happens when I grow tomatoes in self-watering boxes.
This is probably to be expected since potatoes and tomatoes belong to the same family.
I normally see these small shoots on tomatoes in self-watering boxes, but not on potatoes, when I grow them in an ordinary garden bed in the ground. I assume it’s because they have access to everything they need and now have the energy to develop fully.
I remove these small shoots on tomato plants in order to maximize the size of the fruits, but I’ll just leave them here to see what happens.
I have just set up a temporary support to keep the plant upright. It would have been better to use one of my tomato cages from the beginning but I didn’t expect that the potato plants would grow this big.