How to Regrow Onions at Home
If you always want to have an onion (Allium cepa) on hand for your favorite recipes, regrow them at home. It's super easy to regrow onions, whether you want to plant just a few or plant sets of onions. Once you plant your onions, green stems will start to grow quickly.
Steps to Regrow an Onion in Soil
The following steps will show you how to regrow your onions in soil. You can grow them indoors or in your garden.
- Choose an onion or cut off the bottom of an onion and place it in a bowl.
- Add water to the bowl, covering the onion.
- Let the onion soak overnight.
- Plant the onion in your garden or in an indoor container, covering it with soil.
- If you planted your onions indoors, place them in a sunny area.
- Water the soil but not enough to form puddles.
- Water again when the soil dries out.
Steps to Regrow Onions in Water
Growing onions in water is a simple method that doesn’t require much time. You can grow one onion at a time or several onions using jars of water.
- Choose a jar with a mouth that allows your onion to sit on the rim with its bottom inside the jar.
- Add water to the jar almost to the top.
- Set your onion on the jar rim with the bottom submerged in the water.
- Place your jar in direct sunlight.
- Add water as needed to keep the roots in the water.
Always have an onion regrowing at home, and you’ll never have to buy one again.
How to Regrow Onion Sets
Onion sets are small onions produced specifically for regrowing. You can find them at any garden center and plant a whole crop of onions in your garden. Onion sets are convenient and mature quickly because you don’t have to start your onions from seeds.
Plant your onion sets deep enough to cover them slightly with fine soil. Space the onion bulbs about three to four inches apart and in rows of 14 inches. If you want to save time, and you don’t mind uneven rows, you can scatter the bulbs on top of the soil, then place hay over them. Hay allows plenty of air circulation, so the bulbs don’t get too moist.
Water your sets every week and allow the soil to dry between watering. If your onion bulbs become too wet, they will start rotting and fungus and mold growth can occur. Weed around your onions before the weeds grow taller than your onion tops. If any bulbs pull up out of the garden while you’re weeding, just press them back into the soil.
If you planted green onion sets, you’ll have mature onions to harvest in about three weeks. Red onions can take up to four months to mature after planting.