I’m sure many of you have had this experience; you buy onions, don’t use them for a while and they sprout. This happened to me recently. I thought the shoots looked pretty neat so I blasted out a picture on The Glorified Tomato’s instagram. My Sister-in-law commented “Can those be planted to grow more onions, similar to how it works with garlic?” I didn’t have an answer for her, but the truth machine did.
Once an onion sprouts it’s quality for eating slides downhill quickly. You could use it, but it’s not going to be as tasty since it’s putting it’s energy (sugar) to work growing the leaves. Besides composting it, there are a couple other options.
One — set it in a window in a jar with a little water, and let the leaves grow. When they’re a nice size chop them off and use them like green onion.
Two —Plant it. It won’t grow baby onions (it’s not a potato). But it will flower. You can treat that as an ornamental; onion flowers are rather pretty, though not as showy as an ornamental. Or you can let it go to seed and give a shot at growing onions from seed next year.
Picture dozens of these onion sprouts planted in rows, it would make a spectacular arrangement.
I was surprised to notice how similar the onion flower looked to the globmaster’s I have in my garden. No wonder, I discovered that they’re in the same genus!
… And we go full circle. I used the onion sprouts for a salad. The taste is scallion like, not as strong as the onion bulb.