Never Throw Away a Sprouting Onion – There Are Just 5 Steps to Replant it For a Brand New Harvest

It is not uncommon for onions to develop green sprouts during storage. You can safely eat them or regrow the onion – the choice is yours. If you want to try the latter, we reveal how easy it is to plant a sprouting onion.

I do enjoy regrowing vegetables from scraps or cuttings, as it is a very sustainable and rewarding way to get a second crop from sections that many people just throw away. You can regrow lettuce, leeks, celery, onions, and more from scraps, and it is not a difficult task.

Planting a sprouting onion is another way of reusing something unwanted. Sprouted onions have a more bitter taste, so many people may just pull that section out and bin it. It is a much better option to use it and grow another onion, and here are five simple steps to do it.

How to Plant a Sprouting Onion in 5 Steps

You don’t need much equipment to grow onions from a sprouting onion. It differs from growing onions from scraps, where you sprout the cut root end of an onion, as you use the central core of a bulb rather than the base.

Let's look closely at how to plant a sprouting onion and regrow it.

1. Remove the Sprouting Section

A sprouting onion has green shoots emerging from the top of the bulb. The first step is to remove the sprouting sections. It’s possible to get multiple green shoots from one bulb that you can grow into new onions.

Remove the skin and peel away the layers to find the sprouts at the center – the rest of the onion flesh can be used for cooking.

Gently separate the sprouts at the center into sections, each with a bit of the root base attached.

2. Place It in Water

The sprouts need roots to grow. To encourage the development of healthy roots and give the sprout the best possible chance when planted, place them into a container filled with some water.

Each sprout needs its own container, and the base wants to be submerged in water. You can use toothpicks to suspend the sprout.

Place the container in a bright spot that gets indirect light, and change the water regularly to prevent disease or rot.

Once the sprouts have developed roots a few inches long, which should take around a week, it is time to plant the onions.

3. Plant the Sprouts

The sprouted onion can be grown in the ground or in a vegetable container garden if you want to grow onions in containers.

Transplant the onion seedlings and their healthy roots into holes 1-2 inches deep. The sprouted end must point upwards, and the green shoots need to be above the soil surface. When planting multiple sprouts, space them 4-6 inches apart into your vegetable garden beds.

Pick a sunny planting spot where the onions can get 6-8 hours of sunlight a day. Vegetable beds or raised beds should be supplemented with organic matter, like homemade compost or a shop-bought bag of compost (you can get a bag of compost at Walmart), to provide lots of nutrients for strong growth.

If you opt for containers, plant the sprouts in a large container at least 10 inches deep with drainage holes filled with a quality soil for container gardening, such as this Miracle-Gro potting mix at Amazon.

4. Water Regularly

Water the sprouts after planting, then keep the soil consistently moist, but not waterlogged, over the coming weeks and months.

Onions do like moisture throughout the growing season to develop the bulb. However, overwatering is a common onion growing problem that can cause disease issues or even lead the bulb to rot in the worst-case scenario.

A soil moisture meter, like this one at Amazon, can be a sound investment to help you make sensible decisions about when to water plants.

You can fertilize onions with a high-nitrogen feed 3-4 weeks after planting, but don’t feed once the bulbs have started to develop. You can get organic blood meal at Burpee, which is high in nitrogen and helps develop strong vegetable growth, and can help to grow bigger onions.

5. Harvest Your Onions

When you plant a sprouting onion, you do have a choice. You can either harvest the green shoots as they appear and use them like green onions, or leave them to develop into a bulb to lift.

It takes 80-100 days to go from planting to the bulbs being ready to lift. You can tell when to harvest onions as the foliage turns yellow and falls. When this happens, gently lift the onions from the soil and lay them out in a warm, sunny place to cure for a few days.

If you want to store onions for a long time, they should be laid indoors until the skins become paper-dry.

What to Shop for Growing Onions:

If you want to discover more sustainable gardening ideas, we've got you covered. See our guides to growing lettuce from scraps and regrowing leeks using the base that is normally just thrown in the trash.

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