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Get the Facts: Are Sprouted Onions Poisonous?

sprouting onion
Photo: CC0 Public Domain / Pexels - Karolina Grabowska

Despite proper storage, onions quickly sprout if you don’t eat them right away. Are they poisonous, and what can you do with them?

Many of us have been told at one stage or another that eating sprouted vegetables is dangerous. But are sprouted onions poisonous? The myth that sprouting foods are inedible probably comes from potatoes, which can be poisonous at certain stages of ripeness.

So, what do you do if your onions are sprouting? As with sprouted garlic, sprouted onions don’t produce any harmful substances. You don’t need to give a second thought to eating them. 

What to Do When Your Onions Sprout

Because sprouting onions don’t develop toxic substances, you can use them in the kitchen without any issues. Here’s what to do if your onions sprout:

  • Use them as soon as possible.
  • Sprouting bulbs become soft over time, as the shoot eats away at their structure.
  • Older, soft onions begin to smell musty and give dishes an unpleasant aftertaste. Tip: Be sure to smell the onion before using it. Only cook onions that smell fresh and pungent as usual.
  • For older sprouted onions that feel very soft, you’re best off using just the green onion shoots.

Tip: If you’ve got too many to use up, you can try freezing the onions.

9 Dishes to Cook With Sprouted Onions

sprouted onions
A tarte flambée is a great way to use up onions that have started to sprout. (Photo: CC0 Public Domain / Pixabay - Bru-nO)

Sprouted onions are best used for cooking and frying. Due to the lack of crunch, they taste better cooked than raw. They should also be used as soon as you notice them sprouting. Here are some recipes that all require cooked or fried onions:

Tip: The young sprouts of onions have a spicy kick. Use them the same way you’d use green onions in dips or in salads.

Planting Sprouted Onions to Grow Your Own

planting sprouted onions
Plant your sprouted onions in terracotta pots on your deck or windowsill for a rustic and earthy look. (Photo: CC0 Public Domain / Pixabay - Ulrike Leone )

Instead of using them up straight away, you can also plant sprouting onions — they’re the germinated bulb of the onion plant. The green shoots of the onions continue to grow and you can harvest them to add to your dishes.

Growing Onions on the Windowsill

  1. Place the sprouting onions in a small bowl filled with water.
  2. Change the water daily.
  3. Regularly cut off the sprouting greens to use for cooking.

Planting Sprouted Onions in a Flowerpot

  1. Fill a flower pot loosely with soil.
  2. Make a small hole in the center of the pot with your fingers.
  3. Plant the sprouted onion (roots first) in the hole.
  4. Add some additional soil to the pot until the bulb is almost completely covered. The tip of the shoot should be peeking out of the soil.
  5. Water the freshly planted onion, and continue to water every two to three days
  6. Regularly cut off the shoot greens and use them in the kitchen.
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