Accidentally Cooking

Documenting my mistakes in the garden, kitchen and pantry

Sprouted Potatoes and Onions

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The popular wisdom in regards to potatoes and onions, when they’ve sprouted in your pantry, is that they are effectively spoiled or not worth eating. Both become sort of shrunken-looking. Sometimes they start feeling a little soft. In some cases (potatoes and garlic especially) the green parts can lead to a different flavor or less flavor overall. You may be tempted to just throw them away at this point and move onto something with fewer ambitions.

Potatoes and onions (and other taproots, tubers and alliums) represent stockpiles of chemical energy and nutrients for the plants. These plants store significant portions of their sugars, starches and nutrients in these vegetables underground to hedge against winter and drought. Later when conditions are better, these are powder kegs that can quickly explode into new plant life. I planted tomatoes and peppers a few weeks ago and the tallest of them is about 5 inches on it’s tip-toes. Over the course of maybe a week, one of my onions in the pantry sprouted and sent up shoots 5 inches or more, and sent out a whole clump of them. The mass of new green growth coming out of a single onion in 1 week was significantly more than the mass of a tomato growing for several weeks.

Because potatoes, onions and other root vegetables represent storehouses of chemical energy, you can often put those right in the ground and have new plants grow from them (and grow quickly!) The plant will grow, pulling it’s initial burst of energy from the sugars and starches stored in the root. As the plant gets bigger and the leaves start photosynthesizing, excess sugars and starches will be stored in a new generation of tubers and roots for the next season. Thus continues the circle of life.

In the pantry last weekend I found that several of our “Sweet Yellow” onions and several russet potatoes had sprouted and were well past the point where we would be trying to salvage and eat them. I already had some onions planted, but a few more in the garden can’t hurt anything. I had been planning to buy some seed potatoes, but now I don’t need to. If you know how to prepare them, you can plant both these things right in your garden (now is about the time to put them outdoors, if you’re brave enough).

Preparing and Planting Onions

Every onion layer grows up into a single stalk. New layers grow in the middle, pushing up new stalks through the center of the plant. When Onions are harvested and allowed to dry, the outer layers dehydrate and turn into the papery covering we’re all used to, in order to protect the tender inner layers.

To plant a sprouted onion, here are some steps to follow:

  1. Carefully remove the papery outer layers, careful not to damage any roots that are forming (notice that some roots may have started growing under the paper or even between other layers!)
  2. Carefully make incisions and remove remove any layer of the onion which is not currently sending up a viable shoot. Again, do your best not to damage the roots.
  3. As you remove the non-growing outer layers, eventually you’ll reach the live heart of the onion, small bulbs which are each sending up shoots. You may have one in the center, you may have several clustered inside like a bulb of garlic. If many, you may carefully separate them.
  4. Carefully plant these onion cores, sprouts up and roots down, in a pot or directly in your garden, no higher than the very top of the bulb (but make sure at least a teensy little bit of bulb is still sticking up above the dirt line).
  5. Water and care for them like normal.


In this picture, the three closest pots contain my sprouted onions (I’ll bury them a little deeper when I get them into the garden in the next few days). The non-growing layers which you remove are probably perfectly edible. If they look plump and juicy to you, consider using them in food. Waste not, want not.

Preparing and Planting Potatoes

Like onions, the chemicals making up the mass of sprouts come out of the heart of the potato. The more sprouts the potato puts out, the more shrunken, shriveled, and deflated the potato will look. This has lead to a reputation, often undeserved, that potatoes which have sprouted are mushy and effectively inedible or unpalatable. This is probably not the case, but your mileage may vary. If you’re intent on eating them, snap off the sprouts, skin them, remove anything that feels mushy, and cook like normal.

If, on the other hand, you want to plant them, the process is extremely easy:

  1. Fingerling or little potatoes can be planted as-is without any kind of action taken on your part.
  2. Larger potatoes can be cut, to increase the number of plants you start with. Carefully and cleanly cut the potatoes so that each cut piece has at least 2 sprouting (or ready to sprout) eyes on it
  3. Some people suggest leaving the cut potatoes to dry out overnight or longer, to form a dry scab on the cut parts to keep diseases out. Other people say this is not necessary and the potato chunks can be planted as soon as you cut them. I left them out overnight because I didn’t have any place ready to plant them just yet.
  4. Plant the potatoes under an inch of good, fertile soil. There are many many strategies for growing potatoes in buckets, barrels, boxes, bags and other novel containers. Some of these strategies can produce significantly higher yields (in exchange for more materials needed and more effort on your part) than just planting them in the ground. I’ll leave you to do the research on those methods yourself.



All told I ended up with 4 additional plantable onions and around a dozen chunks of potato ready to be planted. I’m not quite sure where I’m going to put these things because almost all of my garden space is already spoken for with the other plants I’m preparing to grow.

Author: Andrew Whitworth

I'm a software engineer from Philadelphia PA. Sometimes I like to go out to my garden, or step into my kitchen and make a really big mess of things.

One thought on “Sprouted Potatoes and Onions

  1. Thank you for this article. I have both onions and potatoes that appear to be garden ready.

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