Introduction: Grow Onions From Discarded Onion Bottoms

Picture of Grow Onions From Discarded Onion Bottoms

This Instructable outlines how to grow fresh onion plants from discarded onion bottoms that would otherwise be thrown in the trash.  You can theoretically create an endless supply of onions without ever having to buy bulbs or seeds, and if you're as big of an onion lover in the kitchen as I am, you'll have a full bed of onions in no time.

3 Week Update:
New roots have formed on the example onion used in this Instructable, and the starts of leaves are forming which can be seen by the two distinct rises at the top of the onion.  This onion will more than likely form two plants just like fully formed example on this Intro page.

4 Week Update:
New leaves are forming above the soil, and it's clear that this plant will be able to be divided.  It has now gone through a hard freeze in its pot sitting on a growing table.

Step 1: Materials

Picture of Materials
You will need:
  • Onion
  • Clean Knife
  • Cutting Board
  • Starter Pot with Potting Soil (optional)

Step 2: Slice Off Onion Bottom

Picture of Slice Off Onion Bottom
Chop off the onion bottom with all the roots still intact.  The more of a bottom you leave on, the better.  Try for 1.5"-2" of attached "meat".

Allow to dry for a few hours to a couple days in a shaded, well-ventilated area to allow for callousing.

Note:  You might only need a few hours for callousing.  If the cut portions are dry to the touch and slightly shriveled, it very well might be calloused enough.

Note:  I'm skipping the dry time for this Instructable.

Step 3: Potting

Picture of Potting

Fill the starter pot 2/3 of the way full and compact.

Create an indentation in the center to cradle the onion bottom and allow for good soil contact.

Cover with 1-2" of soil.

Water as needed.

Note:  You can skip the starter pot if you can't be bothered and plant it directly in the ground.

Step 4: Finish

Picture of Finish

Once the onion bottom has developed a few leaves, remove from the pot.

Remove old onion scales.

Separate plants as needed by slicing between plants and leaving a portion of the roots attached.  You may have more than 1 plant develop from a single onion bottom.

Replant in a prepared growing bed.

Cut leaves down to 1/3 of the size to allow the bulb to develop.  This might seem harsh, but the onion will regrow those leaves with less stress.

Repeat the process.  Harvest as green onions or fully developed mature onions.


boocat (author)2017-12-02

Never thought about doing this. Going to try it! Thanks.

WoundedEgo (author)2013-04-28

I've been doing this for a while now. The onion's new growth will always be from the center area of the onion, so you can peel away most of the old grow before you put it into the soil. I also plant the tops of pineapples. Just pull green part off and tear back the bottom half inch of leaves to expose more of the stalk and then stick it in about a half an inch of water for a couple of days. When the roots have grown out to where they could start utilizing the soil, put them in the soil. They are extremely unfussy. I grow them successfully in medium sized containers and I don't even have to water them. I also grow cumin, fenugreek and mustard from my spice cabinet. I have a three year old avocado tree that I grew from an avocado pit. I grow store bought ginger and turmeric as well. Also shallots, celery and of course onions. I'm in an apartment and the plants are all outdoors (except I just brought in my celery, thanks to advice below) and no one complains. The key to success is the quality of the soil. You have to have container mix if you plant in containers, not "top soil". Gardening is soooo rewarding.

Thanks so much for this information. I am dying to try container gardening, and it encourages me that you are doing it successfully here in Florida. I've hesitated to try because of how awful our soil is and I've been unsure where to even buy good soil for container gardening.

Home Depot.

Unfortunately I live in an apartment and have to keep the plants close to the house where they don't get enough sun. :(

I'm in a house and thankfully have space in both sun and shade but my problem is I don't know enough about gardening to know what grows best in which setting. My mama could grow anything, but she's been gone 8 years now and I have a black thumb. :(

boocat (author)abeautifullife2017-12-02

No problem learning, just get some library books.

Perhaps you should find a nursery in your area and tell them what you want to do and then take their advice, Maybe start with one or two plants until you get the hang of it.

With containers, the way you know when it is time to water (if it hasn't rained) is to put your finger into the dirt about an inch down. It should feel damp there. If it feels bone dry or almost bone dry then it needs water. Otherwise, don't because you'll over-water it.

gjmboulard (author)WoundedEgo2014-07-22

In my place, light is also an issue. I re-grow a lot of veggies with an inexpensive gooseneck lamp. Much to my surprise, bunches of basil and cilantro in glasses of water have rooted and grown into vibrant plants

in organic potting soil.

WoundedEgo (author)gjmboulard2014-07-23

Great! Well be sure and use the new compact fluorescent bulbs because they are actually the same light value as sunlight, unlike the incandescents, and they are a lot cheaper and environmentally friendly to operate.

HigherWisdom (author)WoundedEgo2015-01-25

Never buy or use compact fluorescent bulbs - for any purpose. The science is very clear and voluminous. They damage health and the environment through their entire life-cycle, from manufacture through usage and discard. During usage, they produce unheathy transients in wiring, also referred to as "dirty electricity". They also produce high levels of unhealthful 60 (0r 50, in EU) Hz fields, relative to same-wattage incandescent bulbs. Their light is digital, like a strobe, which is disruptive to brain function and to the corresponding functions in plants. By contrast the light of incandescents is rather constant, closely approximating the signal of natural sunlight. Compact fluorescents do not last as long as most incandescents, needing more frequent replacement; and they expose humans, animals and plants to toxic mercury vapors when broken. Although their combined energy usage is often less than that of incandescents, their dysfunction is more frequent. Don't fall for the compact bulb industry's green-masking! There is NOTHING green about toxic, hazardous compact fluorescent bulbs!

I am not a big fan of CFL's now that LED bulbs have come down in price, but you are making some significantly incorrect claims.

1.) Incandescents are far, far from the 'signal of natural sunlight'. Just because they are simple doesn't mean they are close to full-spectrum. Anyone who grows (or tries to grow) plants with incandescent bulbs is misinformed.

2.) "Dirty electricity"--This sounds like a misuse of the term 'dirty'. As far as I know, dirty electricity refers to inconsistent frequency (i.e. variation from 60.000 Hz) in the mains power. This is caused at the generating station, not caused by use of electricity. AC electricity has a frequency of 60 hz whether its going through a hair dryer, a CFL, or an incandescent bulb.

3.) You claim that CFL's disrupt brain function. Hmmm. OK, even if that is true (and I am skeptical of your 'voluminous science'), what exactly do you mean by the "corresponding [brain] function in plants"? Plants don't have brain functions. They have chlorophyl, which carries out photosynthesis when a photon strikes it. Whether those photons arrive in a steady stream or a pulsed fashion doesn't seem to matter.

namora (author)ryanjohnlenz2016-08-19

When the ballast of a florescent tube is failing they create a strobe affect and this may be what Ryan is talking about. I have read about the problems caused by this.

rfitzgerald1 (author)namora2017-04-18

Fluorescent lights always flash just usually you aren't aware of it and you're right when the bulb or ballast is failing the flashing gets more noticeable. In the USA they flash at the same 60hz as our power system, with old tube tech monitors the refresh rate needed to be higher than 60hz or your screen would have lovely black bands moving down the screen under fluorescent light.

NoreenE3 (author)rfitzgerald12017-11-26

Flourescents are never allowed in my home or work environment and stores or businesses that use them in large quantities I avoid like the plague. My reasoning is quite simple and somewhat unusual, I am allergic to fluorescent lighting. It brings on not only physical symptoms but also neurological and emotional problems. Therefore, everything I grow is with either natural light or plain old fashion light bulbs. Additionally, I ran. an interior plantscaping business and 99 % of my clients did not have fluorescent. This few that did actually had problems with their plants thriving. Just a bit of f.y.I. .

CFL's can produce light a lot closer to the blue spectrum than any incandescent light can and for less money and they hands down last longer. Any photographer will tell you that incandescents tend way more to red, ever take a photo indoors with a film camera (using daylight film) and get that nasty yellow cast to your photos, that's because incandescent light is nowhere near daylight temperature. Today we don't have that problem because digital cameras automatically white balance for the light in the room. I agree with you that LED bulbs are da bomb but so far I have yet to see a LED bulb that is on the cheap side that can produce light close to daylight spectrum, I know they exist but they are generally a sort of panel setup not something you plug into your lamp and very very expensive. So for now, if you need near daylight color light and can't afford a few grand for a professional setup cfl is it.

A friend had an indoor garden using cfl, he had blue for one cycle and red for the other (grow vs. bloom) the plants did well without spending three grand for something like a mercury vapor tech bulb which needed an expensive ballast and sucked a lot of power and made a LOT of heat as well. I think by noise he means the ballast may make "noise" on the circuit which only some very sensitive equipment would be bothered by. In the old days computer techs would tell people not to plug into a circuit with any device that pulled a lot of amperage when it first started up, that included AC units, compressors (as in your refrigerator or a shop air compressor) or vacuum cleaners because that startup usually caused a sort of brown out and then a surge which could damage circuitry and something that created noise in the circuit might affect the shape of the sign wave in the AC current also possibly causing a problem. Tech has grown past a lot of those issues.

Many years ago I recall watching a PBS science show (possibly a NOVA) that investigated how fluorescent bulbs in the workplace could be causing fatigue to people who work under them all day long. While you cannot consciously see a fluorescent bulb flash (incandescent is a heated element while fluorescent tech is a gas that gives out light when it is excited by the small amount of power supplied by the ballast thus the flashing) subconsciously your brain can see the flashing and that could lead to fatigue. The solution for that issue was a ballast that created a faster update but the bulbs were pretty expensive, I do not know the current state of fluorescent tech as to if the new stuff out right now updates faster than the old ones did.

There is a growing belief that some folks are more sensitive to magnetic fields than others and it could cause health issues. Remember those stories about farmers with AC transmission lines over their farms who claimed their cows stopped giving milk? There have also been some reports that people who live near maglev train tracks complain of constant headaches and depression, our brains are electrical why would it be such a stretch that we could be affected by magnetic fields? In Europe there is growing support for an illness called EHS or electromagnetic hypersensitivity syndrome. People with this issue need to live away from all magnetic fields some are so sensitive that even the alternator in the car causes them discomfort, you may say baloney...well no one believed that fibromyalgia or chronic fatigue syndrome were real either for quite some time. Ever have an MRI and wonder why you felt so exhausted afterwards? MRI uses one heckuva strong magnetic field to literally change the magnetic field in your body to create the images. Don't laugh off the idea that some folks could be adversely affected by magnetic fields there may be something to it but I really doubt a couple of cfl bulbs could be an issue but who knows. Remember when cell phones came out, some folks said having them so close to your brain might cause brain tumors and the use of a headset was strongly encouraged. Well somebody also said that when we turned on that new gigantic collider in Europe that we'd open up pinhole singularities all over the world and end our existence too. The point is that we don't know everything.

While it's been shown that plants have at least a simple nervous system (nothing like we have) I'm sort of doubting any negative effects from a cfl bulb. Plants like light and proper soil salinity and water salinity, if they don't get it they don't grow as well and that's that.

TimG90 (author)ryanjohnlenz2016-06-21
DebbieP40 (author)HigherWisdom2016-05-19

totally agree with the craziness of having these bulbs forced on us. Nothing good having these mercury filled things in our houses. Can't even buy the old bulbs anymore.

CaroE1 (author)HigherWisdom2016-05-10

You're right, I've never liked fluorescent lights in offices - hadn't heard of 'dirty electricity'... Found they brought on headaches and just felt generally unwell and there's a hotel near us is lit up with blue lighting from the outside, gives me a headache after just seconds while walking past at night, I wonder what that's about - is it safe?

jan2qr (author)HigherWisdom2016-05-10

Amen on the CFLs! I hate those things!!!!!

MarleneJ2 (author)HigherWisdom2015-09-10

This is SO CORRECT!!!!

one.kender (author)WoundedEgo2015-03-24

No, they don't. CFL's provide horrible light for plants. I added a couple to an earlier indoor setup to add white light so I could see color better...half my plants died. When I ran them through the spec, I found WAY to much high energy UV, which was what fried the plants. Aquarium bulbs, man...we've been growing plants indoors under water for forever.

sfowler1 (author)one.kender2015-11-08

You can absolutely grow under CFLs, it's just a bit of a struggle to find CFLs powerful enough to get a high enough lumen output within your space - and it ends up not being worth it in the end. I've grown with CFLs before successfully - but I absolutely had better grows once I switched to HPS.

namora (author)sfowler12016-08-19

My hardware store has indoor planting CFL's. I made a planting bar with with four lights by simply screwing porcelain surface mounted sockets to a 1x4 with about eight inches of space between them. I then wired them in series and added an extension cord to one end. The board is suspended by a chain at each end and hung from hooks to allow easy adjustment. This is essential because you want to maximise the light getting to the plants without heat damaging the foliage. I was successful in raising many starts with this apparatus that cost very little and was made in a slow afternoon. I understand that LED's may now be found with the proper color balance for grow lighting. These would be definitely worth the expense. When the plants reach about three inches it is time to transplant to encourage healthy rooting. This is at least true with tomatoes.

ryanjohnlenz (author)sfowler12016-06-28

Yep. Fluorescents just aren't that powerful--and that (along with toxicity issues) is their main drawback.

ryanjohnlenz (author)one.kender2016-05-10

I'm no expert here, but I believe that CFL's and "standard" (i.e. tube) flourescents are essentially the same, in terms of their flicker and mercury content. A CFL is basically just the helical version of the tube, with a built-in ballast and standard screw-in socket. People have been growing plants under flourescent lights for a very, very long time with excellent results. I think something else killed half your plants (and besides--why would only half of your plants die if it was UV that killed them?).

one.kender (author)ryanjohnlenz2016-05-11

Actually, not all CFL's are created equal. I'll try to put this as much in k-12 science as I can. You have mercury vapor and argon, xenon, krypton, or neon being super-excited by an electric arc into a plasma. That means electrons are jumping up and dropping down levels in their outer shells. Every time an electron drops down, a photon is emitted in the x-ray range. The x-ray flies off and hits the phosphors on the outer wall of the tube, causing it to emit EMR in the light spectrum. Depending on which phosphor is hit and the frequency of the x-ray, a different frequency of light is thrown off. Different CFL's have different phosphors, and even different numbers of types of phosphors. Looking at them through a spectrum analyzer (the CD/cardboard box spectrum analyzer here in instructables is good enough to see the difference) shows that some CFL's put off as little as four spectral lines while others put off so many, it loins almost like a continuous spectrum. The same is true, by the way, about florescent tubes. Grow lights and planted aquarium bulbs have phosphors designed to throw off light specifically in the PAR range (photosynthetic activity radiation).

As to why the UV spectrum killed half my plants and not all of them, well different plants are sensitive to different frequencies of light. I was growing a bunch of different things in my aquaponic rig. It's near impossible to kill a philodendron. Lettuce doesn't care about the higher energy UV's as much either, but they burned the crap out of my habenero and some of my flowers. When I stopped turning on my CFL's in my overhead lamp and just ran my grow lights, the burning stopped. As far as other issues causing the problem, it's possible, but the system had been running stably for quite some time and my sensor rig and datalogger showed no other changes. I monitor PH, nutrient levels, temperature, humidity, and several other variables as part of the automation I built for the unit... Arduinos and cubbie boards allow for wonderful things, these days and I'm a year away from an engineering BS, so I DO know a little bit about what I'm doing.

ryanjohnlenz (author)one.kender2016-06-28

I understand how electron transitions cause X-ray emission (and subsequent emission of photons from the excited phosphor), but your explanation is true both for 'compact-type' and 'tube type'. I never claimed that "all CFL's are created equal". I said that a CFL and a tube-type fluorescent are fundamentally the same. You claimed that "CFL's provide horrible light for plants", which is an overly-general statement and there are countless successful grows happening under CFL's (as well as tube-style fluorescents). Sure--there is going to be a lot of variation on the spectrum based on which elements and phosphors are used, and this variation *might* be responsible for your die-off--though most CFL's are not designed to put out large amounts of UV. That would obviously be a major safety issue.

But there are a whole lot of reasons that (wouldn't show up on your data-logger) that plants die (or appear 'burnt'), and I'm guessing engineering doesn't focus a whole lot on the biotic factors (i.e. diseases/pests/etc.) affecting Philodendron growth!

At the end of the day, CFL's and fluorescents--like all lighting options--have certain advantages and disadvantages, and are (or, were...) a great fit for certain situations. It does seem that with the drop in price of LED fixtures, the CFL/fluorescent days are coming to an end! (YAY! nobody likes mercury compounds in their home)

gjmboulard (author)WoundedEgo2014-07-23

Thank you, W.E., for your thoughtful response.

I don't use CFLs anymore because they contain mercury.Last year I discovered halogen light bulbs (the same size and shape as incandescents) at "Kmart" (in the U.S.) which were less expensive, nontoxic, and almost as energy efficient as CFLs. The information about callousing veggies (letting them dry for 24 hours) has dramatically improved my results in re-growing veggie stems and roots. Thank you, everyone.

DennisZ10 (author)gjmboulard2016-01-21

The problem with other types of bulbs is their heat and light output per watt. As well as having improper K values.

one.kender (author)gjmboulard2015-03-24

Spices don't typically need much light, but if you look up a few posts, I told a couple other people what aquarium bulbs to buy to provide enough light to grow anything indoors. I even know a few medicinal marijuana users who are using my bulb mix very successfully, even with picky strains. Personally, I just grow flowers and vegetables, but I'm about to get orange and lemon trees...maybe an avocado...and I live in a small one bedroom apartment.

I will do that. Thanks so much for the info! :)

jan2qr (author)abeautifullife2016-05-10

I am in North East Texas & just bought a greenhouse. I too have a BLACK THUMB! I am hoping to learn a lot & successfully grow onions, garlic, shallots, tomatoes, bell peppers, romaine lettuce, broccoli & herbs.

I just did a garden for the first time this year... I got pallets.. Put weed barrier on the bigger side payed it down on the yard and filled it up with soil...(found on Pinterest) then I planted seeds in March and now I have a full pledge garden... If it goes well this year I will do a garden in the ground next year.. My husband wants to make sure I take care of this one first.. I now bought a small green house and am learning to keep my garden going all year long... Thanks to the Internet, Us With black thumbs can grow anything...good luck and don't get discouraged

gardening can be so rewarding yet very challenging even to the green thumbers :) try starting with something that is easy to grow like lettuces or spinach, I'm in Australia, we are a very dry country, so I use our lawn clippings to mulch my gardens, & I grow most things that we eat, including fruits :)

get sum of these

one.kender (author)WoundedEgo2015-03-24

Home Depot...yes. While you're there, pick up a couple 4 ft. 2-bulb T5HO ceiling fixtures, wire them to an old 3-prong extension cord, and order the following flourescent tubes from Amazon or your local pet/aquarium store- 2 Wavepoint Ultra Growth Waves, 1 Wavepoint Super Blue 460, and 1 Wavepoint Coral Wave. A timer is nice, too if you don't want a 24 hr. light cycle. Now, you can grow anything you can find a container big enough for any time of year in the comfort of your living room.

I have found that in South Florida, with a paucity of sunlight, that these are the easiest to grow:

* pineapple
* sweet potatoes
* ginger
* avocado trees
* turmeric
* chives
* basil
* aloe vera

If you want to go with instant success, go with them. No fuss.

One word about Rosemary... Do not overwater!!

jack.luciano1 (author)WoundedEgo2015-04-14

Hey Wounded Ego: Can u tell me how to grow "Ginger". I also live in South Florida, Boca Raton to be exact and grow just about everything. Now all u do, but some,like Pineapple, Potatoes(year Round),Basil,Aloe, its wild and bother some..If u ever want some let me know! I make great organic soil with all left over food scraps, and coffee grounds,etc.. Would like to get in touch and see ur is jack.

RebeccaR119 (author)WoundedEgo2017-03-01

That's awesome. Im doing the same but would love go have turmeric. I posted my onion plant. I was wondering how many onions i will get? Just one?

one.kender (author)WoundedEgo2015-03-24

I realize this is an old post I'm replying to, but I also live in an apartment and my management complains bitterly about anything that's not small flowers in decorative pots (so no brown clay pots). What I have done is set up an aquaponic system in my apartment. T5HO flourescent aquarium bulbs can be mixed to provide an optimal spectrum. I'm running 8 four-foot tubes in fixtures I bought from Home Depot. Lowes only has t8s as of yet. I'm running Wavepoint tubes-4 Ultra Growth Waves, 2 Super Blue 460's and 2 Coral Waves. I'm at about 400 w and cannot grow anything that doesn't like full sunlight unless I keep half of them turned off...but why? That means four fluorescents at 200 w should do you for most plants. Anyway, if you are interested, it really expands the number of plants you can have. What I'm growing in my living room is twice what I could have grown on my porch. I could share build instructions of you would like.

Kweek (author)WoundedEgo2014-05-12

Ridiculus innit? My plant's just make me happy for no good reason. I have a little mango tree that sprouted in the compost pile that makes me smile every time I see it.

RussellP32 (author)2017-10-09

I started a Celery plant by floating the cut off in water. It grew fine for about 3 to 4 inches, but did not have roots showing. I placed it in Dirt in a pot, and it simply died then.

shezzi177 (author)2017-06-17

Hi I've planted the onion bottoms in a pot and covered them with 2 inches of soil. How often should I water them? Thanks in advance!

LindaB358 (author)2017-04-10

I have done this with leeks. I cut the very bottom off. And let them set to heal over the top for a day or two. Planted them down back and ended up with more. However they came back best after they went through a winter cycle. Was wondering if any one has done it right after they are cut, or do they let the tops dry out a day or two first.

RebeccaR119 (author)2017-03-01

I figured this out a while ago doing compost. This is my first real success so far. I was wondering, how many onions will i get?

Ben Eby (author)2016-05-26

This is fantastic to know - I have been doing this for a while with celery but never thought of trying an onion

MarieI6 (author)Ben Eby2016-06-14

How is it done with cellery? And is it only the rooty part or also the top?

Daggery (author)2016-05-30

Nice! I'm gonna try this today! I'll add some photos if I'm able to make something grow!!

IknowHEis (author)2016-05-05

I have questions.... What is the right potting soil? How long does this process take? Direct sun or indirect sun? What time of year? Cold or heat tolerant? I live in Las Vegas and plan to shade them most of the day because it gets soooooooo hot, will that work? Will they grow in this heat? How much water? Fertilizer? Thank you so much!

Rainastra (author)IknowHEis2016-05-11

You need a good quality potting mix from your nursery/garden supplies. It will contain the required fertilizers and nutrients. Eventually, these will need topping up. The 'el cheapo' mixes don't contain all the good stuff but they also don't absorb water well. Your nursery people can advise you as to which plants require which nutrients. Because of the very hot conditions, it is not advisable to use terracotta pots as they dry out quickly. If you're really insecure about watering, I suggest purchasing a moisture measuring thingy at the nursery or garden supplies outlet. I paid about $12AUD for this thing and it's very useful for pots. (It will be cheaper in the U.S.) It will show how deep the moisture is. I have seen friends grow great veg. in fish bins. They are only about 30cm deep x 70cm long approx. and 45cm in width. I suppose each would hold a 50litre bag of mix. You are a long way from the coast but there are similar sized storage containers on the market and you just need to drill holes. Don't forget to mulch, especially if pots are in sun and wind. Good luck.

About This Instructable




More by AngryRedhead:Bananas Foster CocktailDeli Roast Beef in a Slow CookerBourbon Pecan Pie Candy Balls
Add instructable to: