Growing Onions From Sets

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Onions are a great crop for the homesteader to learn how to grow because it’s so useful and stores very well for months. Growing onions from sets is the easiest way to go about it. In this post, you’ll learn how to grow onions from sets…

I love growing onions!

First, I’m an Israeli… If you are even just a tiny bit familiar with the Middle Eastern diet, you know that practically every dish starts with onions.

They give so much flavor to anything from egg salad to canned stewed tomatoes to a zucchini casserole or anything in between.

Second, they are very easy to grow… You just have to make sure that you choose the right variety and start from sets or plants (we’ll talk about all that in a minute).

Third, they are easy to store! Even if you don’t have a root cellar or any other type of cold storage you can store onions for months with relative ease. Or you can make onion jam and preserve them this way.

Growing Onions From Sets…

Growing onions from sets is very easy! Onions are a great storage crop and are relatively simple to grow especially if you start from sets. Here is everything that you need to know...
#growingonions #onionsets #plantingonionsets #organicgardening

Aside from curing them and storing them whole for the winter, you can also preserve onions a million different ways.

They can be made into a delicious jam that goes so well with any kind of meat or cheese, they can be dried, canned, fermented or even frozen…

There are just so many things one can do with onions!

But not all onions are the same… So that we have a better understanding of our options and what’s best for a homesteader to grow, let’s list the main types of onions to choose from…

Kinds of Onions To Grow…

Multiplier onions.

Green onions – Also called bunching onions or spring onions. They have a mild onion flavor, they are hardy and versatile. You can add them to salads and soups and casseroles…

They are relatively easy to plant and grow directly from seed. They don’t have many pests and are easy to pick and use.

I always have them in my spring garden but I don’t call them a main crop. I mostly use them in salads. Also, we don’t start them from sets so they are not the ones that we are going to focus on in this post.

Mini onions – Kind of like spring onions and can be used in the same way but if you like, you can leave them in the ground a bit longer and let them form a golf-ball size bulb.

They can be planted very close together and are easy to start from seed just like the green onion. They are fun to grow but I am not considering them a main crop as well because they aren’t easy to store for a long time.

Multiplier onions – I guess that you can think of them as a combination of green onions and mini onions. Every plant produces a cluster of 7-8 bulbs that are small… About 2” across.

They might be fun to grow but I personally don’t think that they are as easy to use as the other kinds of onions. You can learn more about them here. They are the ones that you see in the picture above.

Egyptian walking onions – A perennial onion. You plant them once and they “walk” and multiply. You can use both the greens and the onions.

They are a top-set onion. Meaning the bulbs form on the top of the plant and not on the ground… Kinda crazy, I know.

You can harvest the small bulbs or let them fall to the ground and form another plant (hence the walking…).

They are definitely not a main crop but the cool thing about them is that they are hardy and you can leave them in the ground year-round. So really, you can have onion greens and tiny bulbs in the middle of the winter.

You can learn more about them here.


Shallots – Can be considered a combination between garlic and onion. They are small and flavorful. They are easy to grow and are healthy and tasty especially when they are used raw since they often lose some of their taste when cooked.

I think they are fun to grow from seed and have on hand. They can be cured and kept for months but I don’t consider them as main crop either.

Cipollini onions – A type of Italian onions. The bulbs are smaller and somewhat flattened. They are sweeter than most onions and are delicious raw or added to dishes.

Another great thing about them is that you can use them as bunching onions or you can let them form a bulb.

I think they’re a great option if you’re not a heavy onion user. If you want a variety that you can use as both a bunching and cured onion and if you are looking for a smaller variety.

Just like the full-size onions, they come in red, white and yellow. You might be able to find sets for them but it’s most common to find plants or seeds.

Full-size onions – These are the ones we are going to focus on in this post.

We all know them very well, the full-size onions we use when we cook (although they can be eaten raw too).

They are definitely our main crop and are easy to grow, cure and store for months.

You can view some of the onions I’ve talked about above on the Johnny’s Selected Seeds website here. I’ve purchased onion sets, plants, and seeds from them before and they have a great product.

However, I often just get my onion sets at one of the farm supply stores in town or even at Walmart. They are usually easy to find in early spring.

Varieties of Full-Size Onions…

Large, full size onions.

There are so many varieties of onions… There are yellow, red, and white varieties and they can come in slightly different shapes.

Onions get their cue to start bulbing from day length. As soon as days reach a certain number of hours in length, onions switch their attention and focus from growing healthy and strong tops to forming a bulb.

Depending on where you live, you’ll have to choose the right variety of onions according to your location.

What’s important to remember when choosing a variety of full-size onions is that they are divided into 3 groups…

Long-day onions – These onions are suited for the northern states, growing zones 6 and below.

Long-day onions start to form a bulb at 14-16 hours of daylight. They are usually planted in late winter or early spring.

Intermediate-day – These onions are suited for the states in the center of the U.S. in growing zones 5, 6, and 7. However, they are more adapted than the long and short day varieties and will bulb in most locations.

They will start forming a bulb at 12-14 hours of daylight. They can be planted in fall or early spring.

Short-day – These varieties are suited for the states in the deep South, growing zones 7 or warmer.

They will form a bulb at 10-12 hours of daylight and are usually planted in the fall and mature in late spring.

So really, you can see that your success in growing large and beautiful onions starts from choosing the right variety of onions. Make sure that you take a moment and choose carefully before you order your onions.

You can find more information about long, intermediate, and short day onions and a list of varieties suited for each location here.

Ways to Plant Onions…

Now that we’ve figured out what variety of onions we should grow, let’s talk about our planting options…

There are three ways to plant full-size onions…

Start onions from seeds – If you choose to start your onions from seeds you will have to do this inside the house.

Onion seeds are planted in open flats, you fill a flat with a good seed starting soil and spread a lot of seeds all over before placing the flat under growing lights (read more about: indoor seed starting and DIY grow light shelves).

When the plants are 8” tall, you give them a “haircut” (they are thin and look like hair) and cut them back to 4”. You do this a few times to encourage the plants to thicken instead of to grow tall.

When the plants are the thickness of a pencil they can be hardened and planted outside (here is more about transplanting seedlings to the garden).

This is totally possible but it is a lot of work, therefore, most small farmers or home gardeners prefer one of the next two options…

Plant little onion plants – Basically you purchase the result of the work that I described above. You are purchasing pencil-size onion transplants.

They come in bundles and are very simple to plant. You simply dig a hole 3” deep and drop an onion plant in the hole, cover it and call it a day.

Grow onions from sets – Sets are also very easy to plant. Essentially, they are little onion bulbs… In other words, immature onions that were grown the season before and dried.

I like them better than the plants because they are not storage sensitive. I can leave them in the house for a couple of weeks if I didn’t manage to prepare the garden bed or if something unexpected happens.

They are dry and as long as they are stored in a dry and cool place they’ll be okay for a couple of weeks.

If you choose to grow onions from sets or from plants, the information below will walk you through the steps…

When to Plant Onion Sets…

We mentioned this a little before when we talked about the different types of onions but let’s mention it again here…

If you live in the northern climate and grow long day onion varieties from plants or sets, it’s best to plant them in late winter or early spring, as soon as you can work the soil.

Onions are very hardy so even if you know that there are still going to be frosty nights don’t worry, the onions will do just fine.

If you plant really early, a good idea is to mulch the onions with some leaf mulch or straw mulch to protect them just a bit.

If you grow intermediate varieties, you have the choice of planting them in fall or early in the spring as soon as you can work the soil.

If you plant in the fall, the onions might grow a little bit and then when winter comes they will most likely “go to sleep” and will wake up and start growing again in the spring when the weather warms up a bit.

If you plant in the fall, it’s a good idea to cover the plants with mulch to protect them through the winter.

If you live in the south and grow a short day variety, it’s best that you plant your onions in the fall. Since winters are not too cold and onions love the cool weather, they’ll keep growing through the winter and should be ready for harvest in late spring.

How to Plant Onion Sets…

Preparing the bed for planting.

Plant your onions in full sun (read more about choosing the best location for a vegetable garden).

Onions love rich, well-drained soil, with a regular pH for a vegetable garden (6.2-6.8). It’s always a great idea to add compost to your garden beds before planting.

You can definitely plant onion sets in rows but I love growing onions in raised beds because of the fact that they love well-drained soil and soil always seem to drain better in raised beds.

If onions sit for too long in wet soil the bulbs will rot and you’ll lose your onions.

This happened to me one year when I mulched my onions too heavily. Onions don’t have a lot of leaves that cover the soil so it’s easy for weeds to germinate in the onion bed.

I tried to make my life easier by mulching with straw mulch so I wouldn’t need to weed as much. The result was that the mulch kept the soil too moist around the bulbs and they ended up rotting.

Since that year, I plant my onions in raised beds and go really easy on the mulch, especially during bulb formation and a couple of weeks before harvesting.

Marking a pencil.

Before we start sorting the onion bulbs I want to mention a nice little trick that I like…

I take an old pencil and make a mark 2” from the bottom with a Sharpe (it’s faded in the picture above. It’s right when my thumb is). This little pencil helps me plant the sets in the right depth. You’ll see in a minute how I stick it in the ground to make the planting hole.

Preparing Onion Sets for Planting…

Growing onions from sets.

I usually grow yellow onions, but this year, I saw this bag of mixed onion sets at Walmart and decided to give them a try.

A bag with onion sets.

They come in this bag that has holes in it. I purchased it at the end of February and kept it a couple of weeks until my garden beds were ready for planting.

That’s the nice thing about onion sets… Since they are dry, you can keep them for a while. However, make sure they are stored in a cool and dark place until you are ready to plant.

A bowl with onion sets. Growing onions from sets.

Once I was ready to plant, I emptied a couple of bags of sets into a kitchen bowl…

Removing bad onion sets.

And sorted them. Sometimes you can find rotten sets, or empty sets like the one that you see in the picture above… Take them out.

A healthy onion set.

Also, it’s a good idea to sort the sets by size. Place the larger, most beautiful sets in a different bowl and make sure to plant those first. When growing onions from sets, it’s best to start with the best, firmest, and largest sets.

Just in case it crossed your mind, let me mention that you don’t need to peel the sets. We are going to plant them just as they are.

Also, you might find sets that have already sprouted and have green tops. You can definitely plant those as well.

How to Plant Onion Sets…

Making the planting hole using the pencil.

So the garden is ready and the sets are ready… Let’s get planting.

It’s very simple, you make a hole that is about 2” deep (you can see that I am using my pencil. I stick it in the ground and move it around a bit to create the hole. Of course you can dig the hole however you want)…

Planting onion set in the bed.

And you place the set in it with the root part down (same way that I am holding the set a couple of pictures ago…).

Covering the sets after planting.

Then, all that is left to do is cover the hole and water.

Inside the row, you want to plant onions 4”-6” apart. The distance between rows should “traditionally” be about 12” apart.

However, when I plant onions in beds as you see above I ignore the row spacing and just make sure that each set has 6” space in all directions. As long as the bed is filled with rich soil and as long as I feed my onions enough, they will be fine close together.

I usually dig all the holes, place the sets in the holes, and then cover all of them at the same time.

Growing Onions From Sets…

When growing onions from sets, a couple of weeks after you plant them, they will germinate and your onions will start growing green tops…

Watering – Like most vegetables, onions need about 1” of water a week. About two weeks before harvesting, you should water less. This will help the bulbs to firm, harden, and start the drying (curing) process.

Mulching – As I mentioned before, you gotta be careful when mulching onions… If you plant your onions in the fall, go ahead and mulch them for winter (here is how to use leaves as mulch).

As long as there are only greens, it’s ok to have mulch around your onions. But I highly recommend that you pull the mulch away from the plants when they start to form bulbs.

Mulch stores moisture and keeps the soil very moist. If the area around the bulbs stays too moist for too long they will rot and you’ll lose your onions.

Fertilizing – Onions have shallow roots and are only able to source water and nutrients from the surface of the soil. This is why they will benefit greatly if you feed them a bit.

It’s always a good idea to add compost before planting. My favorite is cow manure.

As the onions grow you can feed them every two weeks with blood meal, fish emulsion, Espoma organic fertilizer, and/or worm castings. They will add nitrogen which will support healthy top growth.

To add potassium and phosphorus, you can add wood ashes to the bed if you have it (6lb per 100 square foot. I admit that those calculations always confuse me… I just add a little bit of wood ash around the plants).

Remember to stop feeding the plants when you see that they start to form bulbs.

Weeding – Onions don’t have full, bushy top growth… This means that they don’t shade the ground and it’s easy for weed seeds to germinate and grow.

On the other hand, we don’t want to mulch heavily so all that is left to do is get on your knees and weed the good ol’ fashion way by hand.

It’s not too hard if you do it often. Pull the weeds while they are small so they don’t go to seed and spread. Do it often and it will only take a few minutes at a time.

Pests – I have never had any pests bother my onions…

If something bothers your onions it’s probably…

Thrips – They are fat, tiny insects (about the size of the head of a sewing needle) and they live on the green tops of the onions. You can spray insecticidal soap to kill them.

Onion maggots – This is another good reason to keep mulch away… The insects love decaying organic matter and will lay their eggs at the base of the plant especially if it’s moist and nice and warm down there.

You can cover your plants with a fine mesh netting when the onions start to form but most of the time I feel that it’s enough to keep the area around the bulbs dry.

If you live in a wet climate, you might need to use the net though.

When and How to Harvest Onions…

Harvesting onions from the garden. - growing onions from sets.

Generally, you can pick onions whenever you want. When they reach your desired size, you can pick them and use them.

However, most of the onions we grow are for long term storage so we want to wait until they reach their full size.

Once that happens (most onion varieties mature around 90 days after spring sowing) you’ll notice that the neck of the onion plant starts to soften and the tops fall over and start to dry at the end.

When the majority of your plants reach this stage, feel free to help the others along by bending over their tops as well.

Now, wait a few more days and then harvest your onions by gently pulling them…

Curing and Storing Onions…

Shake the extra dirt away and lay your onions in one layer in the sun for a week to cure (do not peel or wash your onions).

It’s best to time your harvesting in a way that you can leave the onions outdoors in the sun (so harvest when you know that the next week is going to be sunny and there isn’t going to be any rain).

However, if you harvest before the rain you can always cure your onions indoors in a dry and well-ventilated area.

After about a week of curing, your onions are ready for storing. You can braid them and hang them or you can cut the tops off and add them to mesh bags.

Then store your onions in a dry cool place for the winter.

Aside from the fact that there might be a little bit more weeding involved with growing onions, growing onions from sets is pretty simple.

Growing onions from sets is easy… They are large enough that it’s easy to plant them in the right spacing and the onion plants are very hardy.

I grow as many onions as I can store every year but I hope that one day I will have a nice root cellar so I can grow many more.

I hope this was helpful!

If you liked this post, you might also like…

How to Plant and Grow Asparagus

Benefits of Cover Crops

How to Plant Sweet Potatoes

How to Plant Bare Root Strawberries

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14 thoughts on “Growing Onions From Sets”

  1. Heißer Verkauf Adidas Ausbildung

    Heya! I’m at work browsing your blog from my new iphone 4! Just wanted to say I love reading through your blog and look forward to all your posts! Keep up the excellent work!

    1. Thanks! And congratulation on your new iPhone 4! I now have the iPhone 6 and I have to tell you, I liked my 4 much much better :-).

  2. I Planted my onions this year and I am surprised how high the roots go ! They now have lovely tiny white flowers. What should I expect next ?

  3. Your way ahead of me! It has been such a cold Spring, I haven’t even thought about starting. But I need to! Thanks for the tutorial 🙂
    Stopping by from the HomeAcre Hop.
    Thanks for linking up!

  4. Hi Lee, I grow onions from seed and purchased sets. I never thought of planting onion sets in the fall like garlic. I wonder if they would survive our cold winters. I may have to give this a try this fall using some of the smaller onions from the harvest.

    1. I am going to give it a try too. Our winters are not bad as the ones up North but still freezing at night. Will be interesting to see if the’ll survive.

  5. Hi Lee. I am trying onion sets for the first time this year so thank you for this post. We live in Northern Vermont so there’s just not enough growing season to start onions from seed (outside anyways). I plan on planting them this spring and we’ll see how it goes!

    1. Good luck! I think you are doing the right thing by starting with sets. Hopefully you will have a nice harvest at the end of the season.

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