Growing Onions indoors – 6 Ways to Grow Onions in Containers

Onions are easy to grow both outdoors and inside.  They are one of those vegetables that I never seem to have enough of because I use them every day for cooking. This article shows you how to use onions as indoor plants. Growing onions indoors is a fun project and one that the kids will love to help with.

Many gardeners think that they would love to grow onions, but they also assume that one needs a large amount of space to grow them. This is not necessarily the case and there is an easy answer to this problem.  Just try your hand at growing onions in containers. Doing this will allow you to have onions growing on a small patio or deck garden, or even have them growing inside your home. Growing onions indoors is a fun project that the kids will loveIf you don’t have the space for a  full scale vegetable garden outside, you can still grow onions indoors. You can even have an endless supply of them if you do it just right since onions are a cut and come again vegetable.  (they will regrow from the original stock with roots.)

Onions are a very persistent vegetable. They will sprout, regrow, and sprout again. Just look at this basket of them. Many have already sprouted and could be used to make new plants.How to grow onions indoors. Sprouted onions will re-grow if you plant them in soil or water

Growing onions indoors gives you an endless supply when you need them.

There are lots of ways to grow onions outdoors, but they usually require a big garden space. Outside, onion sets are often used,(basically small undeveloped onions) but when we are thinking about the task of growing this useful vegetable inside, we have to think outside the box.

Most of these ideas will end up giving you onion tops, rather than onion bottoms, since those require quite a bit of space to grow. But the sprouts of onion have a lovely taste, too, and can be used in all sorts of recipes, in addition to using them as garnishes.Growing Onions Indoors is easy

For today’s project we will focus on the ways to grow them in a more confined area. Here are a few of the ways to grow onions indoors.  Kids will love these projects too!Spring onions will re-grow

Growing onions in containers

Growing onions in pots is easy.  You won’t get a large crop like you do outside, but the top will give you a part of the plant that you can use in recipes. Place a small whole onion in potting soil in a pot and it will spout new growth.  You can either slice off the onion where the roots are, or place a small whole onion on soil and it will grow, in time. When it has developed repeat the process as often as you like. 

Onions will grow from the base and will sprout on top.

Growing onions in water

Onions don’t even need soil to grow. Growing onions in water is a project the kids will love because they can see the roots growing through the sides of the glass.

If you place a sprouted onion with the roots down in a glass of water, it will continue to grow on the top with new shoots.  You can either cut off the top part and use it in recipes, or plant the whole onion, roots and all, in soil and watch it grow.

Onions growing in water.

Onions can be a decorative plant too, as this photo shows. The onions are sitting in a bowl of water lined with pebbles. I also force paperwhites using the same technique with great success.

Onions in water with rocks

All types of onions will regrow.  One of my latest experiments was to try to grow vidalia onions from bottoms that would normally end up in the trash or compost pile. My onion sprouted quickly and gave off new growth in just a few days.

Growing onions from onions

Don’t discard those old onion bottoms in the trash.  You can create an endless supply of them without ever having to buy more. This can be done with all types of onions.

The roots of onions are very persistent.  In this photo whole onion bottoms are sitting on rocks in a dish of water and the green sprouts are growing.  If you cut off the green parts, more will grow.Vidalia onions sprout and will re-grow easily in a pot.

Cut and come again onions

Growing green onions indoors is a cinch! This is one of my favorite ways to grow onions.  I buy one clump of spring onions at the store. Then I place them in a jar of water and cut just the green tops for recipes.  You will have new growth before you know it and never have to buy spring onions again.  See my tips to re-grow spring onions in water here.

Growing green onions in water can be done in just one week.

Growing Onions Vertically in Soda Bottles

This idea is such a fun one for kids to do.  Grow onions vertically on a window sill.  You will need a 5 liter bottle that you have made holes in. Fill it with potting soil and onion sprouts and watch your harvest grow indoors! The kids will be fascinated growing onions when they see the soda bottle covered with onion tips that have grown out of the holes in the bottle.Growing onions vertically

Growing Onions from Seed

Spring onions don’t take up much room outside and will send up flowers quite easily. I had one batch that took up just a square foot of space and it lasted about 4 years before it finally gave up the ghost. Onions are biennials and will produce seed in their second year.

The plant sends up stalks with flower heads on them. These are called umbrels. When they go brown, cut them off the plant and place them in a paper bag and allow them to dry completely for a few weeks.

Once dry, give the bag a shake to separate the seeds from the other matter in the flower head and store them in a cool, dry place. The seeds can be used to plant in soil both indoor and out and spring onions grow very easily indoors from these seeds. (Store bought seeds work too.) Grow lights are a big help for starting seeds indoors.

Flower umbrels on on spring onions produce seeds. Growing onions from seed indoors is easy if you dry the umbrels out completely.

Onions sprout easily and that is good for getting more plants for free.  This project can be done on a deck.  Get a 4 gallon container and add some wood chips about half way up.  Fill the rest of the pot with potting soil. (the wood chips will act as drainage.)  

Keep the soil evenly moist and the sprouted onions will grow for you.  The roots on the bottom will love the new, rich soil!

Sprouted onions will grow

Do you ever reach into the onion bin and find an onion that has sprouted where the sprout actually splits the onion?  Don’t just use part of it and discard.  Put that sprouted part to work. 

Slice into the onion to expose the sprout and carefully cut the onion in two (take care not to disturb the sprout).   Carefully cut around the sprout and plant.  You can use the part not planted but will end up with another onion too! 

This onion has sprouted and split the skin

Admin note: This post first appeared on my blog in January of 2017. I have updated the post to add more information and photos and also added a few new ways to grow onions indoors.Growing Onions indoors is really quite easy. Onions are persistent and those roots just want to keep growing. See several different ways to grow onions indoors.

Have you discovered other ways for growing onions indoors?  Please share your tips in the comment section below.

Disclosure of Material Connection: Some of the links in the post above are "affiliate links." This means if you click on the link and purchase the item, I will receive a small commission from the sale, but the price is the same for you. I am disclosing this in accordance with the Federal Trade Commission's 16 CFR, Part 255: "Guides Concerning the Use of Endorsements and Testimonials in Advertising."

  21 comments for “Growing Onions indoors – 6 Ways to Grow Onions in Containers

  1. Joanne Castle
    09/05/2013 at 1:52 pm

    Looks like fun!

  2. Vicki Bruni
    09/10/2013 at 10:12 pm

    I think that the idea of growing onions indoors is great!!

    • Stella
      03/31/2018 at 10:53 am

      I tried growing an onion by starting it in a glass of water. I had great looking roots so I put the onion in soil. After a few days the onion was getting moldy. I kept it for a few days but am thinking about throwing it out. Can you help me

      • Carol
        04/03/2018 at 10:08 am

        Hi Stella. It sounds as though the onion rotted when you planted it. Once this happens, there is nothing you can do. Carol

  3. Josey
    11/28/2013 at 4:48 am

    Wonderful idea

  4. Kathy
    08/31/2014 at 1:02 pm

    This is great I am starting right away

    • admin
      08/31/2014 at 10:20 pm

      Hi Kathy. God luck with them! Carol

  5. Tammy
    07/31/2015 at 12:51 pm

    How can I get the hole big enough for the onion to be pulled through after it’s grown – and yet not so big that the soil falls out?

    • admin
      08/01/2015 at 12:39 pm

      Hi Tammy. These are not my projects. I shared them from the site where I found them and linked to them in the article. If you follow the links to the site, they may be able to answer your questions.
      Carol

  6. Edrece
    08/27/2016 at 3:13 am

    I’m Kind of confused here im only 16 and Ive just started my own vegetable garden Can Some one explain this in dummy terms

    • Carol
      08/27/2016 at 10:21 am

      Which part is confusing to you?

  7. Nadia
    04/30/2017 at 10:05 am

    If i planted a red or yellow onions​ in a pot, are they going to produce a real red and yellow onions again?! And when i should harvest them?
    Thank you.

    • Carol
      04/30/2017 at 12:54 pm

      Hi Nadia. Probably not if you keep them in a pot, unless it is large and kept outside. Onions need the coldness to develop a bulb. You could start them in a pot and then plant in the garden, but it does take months for onion bulbs to form.
      Carol

      • Nadia
        05/02/2017 at 7:46 pm

        Thank you so much 🙂

        • Carol
          05/02/2017 at 9:44 pm

          My pleasure Nadia. Carol

  8. Jess
    09/09/2017 at 5:05 pm

    Do you only get one onion from the roots and sprouts.?

    • Carol
      09/09/2017 at 8:34 pm

      Yes but you can divide it again, with each part having roots and a growing tip. Carol

  9. Lena
    02/22/2018 at 2:13 am

    Thank you for sharing! My little tribe and I are planning on having an indoor garden this year full on and we all love onions 🙂

    • Carol
      02/22/2018 at 9:46 am

      Hi Lena. Hope you have fun with it with your tribe! Carol

  10. Toni
    03/02/2018 at 9:59 am

    I’m just interested to know if you can grow them in planters as houseplants not to harvest. I like the long green growth and would just like a house plant. Can that happen

    • Carol
      03/02/2018 at 10:58 am

      Hi Toni. Yes, you can grow them this way as long as you have them in a very sunny window. Vegetables need a lot of sun even when grown as houseplants or they will “reach” for the light and get spindly. Carol

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