How To Grow Onions In Canada

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If you’re trying to grow onions in Canada there are some things you need to consider. This Gardening Canada article is going to look at how to grow onions in Canada. This will be an absolute complete guide to starting seeds indoors and even looking at whether or not sets are a great option for you. 

If you are new to this blog my name is Ashley and I am a soil scientist. I am located in a Canadian Zone 3 and a USDA Zone 4. I write articles, make YouTube videos, Instagram & Facebook posts all designed for Canadians and Cold Climate gardeners using science-based methods. If you are looking for anything specific be sure to let me know in the comments down below.

The Best Onions Variaties To Grow In Canada?

If you’re simply looking for different varieties you can purchase. Or are simply wondering which varieties are best suited for a Canadian garden then check out these links down below? These are the best options when it comes to growing in Canada coast to coast. These onions will grow big & healthy in zone two upwards. 

XXL Kelsae Sweet Onions – These are the biggest onions you can grow and they taste amazing. Seeds need to be started indoors.

Apache Scallions – Perfect for on-demand cooking & a short turn about to harvest. These are seeds with only 65 days to harvest. These can be seeded directly or started indoors early.

Yellow Onions Sets – These are the bulb forms of onions that can be placed directly into the garden.

Red Onions Sets- These are the bulb form of red onions that can be placed directly into the garden.

Welsh Onion – Look identical to a Leek but easier to grow in some cases

Do You Grow Long Day Or Short Day Onions In Canada?

One of the first things you wanna look at when determining which onion variety you want to grow is long-day versus short-day onions. Onions can be divided up into two different groups.

One group of onions grows best in environments that have short growing days. All the other group grows best in environments that have long days.

Here in Canada, it is not uncommon to have the sun up and illuminate the sky till 9 o’clock at night. This is a great indicator that you need a long day onion. If you get a short day onion and try to grow it in a long day environment you will end up with poor results. For all the onion varieties I am giving you links to are considered long day onions. This means they grow best in Canada and the northern US.

In Canada Should You Grow Onions From Seeds Or Sets?

Seeds Vs. sets is a controversial topic. Some people believe sets do not get as large. And this is because of the stress caused when the plant is removed from the soil and shipped. Set are incredibly convenient because you do not need to start them early indoors. They are the perfect candidate for anyone who has limited growing room inside.

Set are made by planting onion seeds the year before. These sets are harvested in the fall and then sold to you. Essentially a set is a baby onion that has not yet fully rounded it out. When you plant in your garden you are simply just completing the lifecycle and helping the bulb engorge further. 

Onion sets do not need to be started indoors. And preferably they will be started outdoors when the soil is thawed. Whenever planting any sort of onion crop you do you want to try to get them set in the ground early in the year. Onions do great in cool soil & it is a great way to avoid bugs eating the bulb. 

When Should You Start Onion Seeds Indoors In Canada

When it comes to planting onion seeds in Canada you will need an early start. Onion seeds need around 100 to 120 days to mature in most cases. The good news is that onion seeds are relatively easy to keep indoors. We do not often see lagginess in onion seeds due to improper lighting. 

If you were choosing to grow your onion seeds from seed then you’ll want to start them indoors between February and March. This will allow enough growing time before they need to be transplanted outdoors. You may be thinking that is a drastically early start. And for most plants, it would be considered too early. However, with onions it is perfect timing.

However, when growing onions we need to keep in mind that they do enjoy cooler soil. If you want a larger bulb that is not affected by bugs then cold soil is ideal. This means our onions will be planted outdoors sooner than our tomato plants. 

It’s important when transplanting our onion seedlings outside to keep in mind spacing. Onion seedlings are going to appear very tiny. Therefore we may assume that they do not need a lot of space. However, if you are aiming for larger size bulbs then space is ideal.

What Type Of Soil Do Onions Like To Grow In

Onions are best grown in the ground and not containers. There’s a number of reasons for this but the main reason is temperature. Container gardens tend to get a little bit warm. And with onions needing full sun for proper development it may be difficult to achieve this in a container.

The ground that you use should be amended with manure if possible. Onions have a high affinity for sulphur and that is we give them their taste. Manure is an organic amendment that is typically higher and sulphur concentration. This additional help ensures larger bulbs that have a more pungent taste and smell. Which is exactly what we want for onion growing.

With onions, it’s important to keep in mind that we want the bulb to mostly grow above ground. This means we do not want to plant the set or seedling too deep. This also means you want light fluffy soil that is going to allow the bulb to develop.

Always follow the planting depth directions on the seed packet or set packet for your onions.

How Often Do You Water Onions

It is particularly important that you cut off water towards the beginning of August. August is the time in the onions are beginning to mature. Excess water will hamper the onion’s ability to store indoors. This is why they should be offered a little to no water during August month. This will help ensure proper curing and ultimately better storage.

Scallions Vs. Onions

Scallions and onions are very similar. This goes for both the way they are planted and the way they are harvested. You can also get scallions in seed form or set form. The big difference is the size of the bulbs. Scallions typically are much smaller in size and have a less intense taste. Scallions are more commonly used in dishes that don’t require a heavy onion flavour.

If you choose to grow scallions or onions you will be able to grow more plants. This is due to the smaller bulb size and therefore less space is needed. The growing instructions are identical to that of an onion. This means scallions still need to be started early indoors if you’re grown from seed. Scallions also enjoy being planted into cooler soil temperatures for the same reasons as onions.

Onions Vs. Leeks 

Onions and leeks are two very different plants. Onions and Leys are actually grown drastically different from one another. Do you want to learn more about how to grow leaks in Canada then be sure to check out this post. And if we go through how to grow leaks from start to finish.

Why Are My Onion Stalks Falling Over?

You’re going to notice that towards the end of the season your onion leaves will begin to fall over. It may not be all the leaves themselves and it may only be a few at a time. This is a sign that the leaves are getting too heavy to support. This means that the onion bulb is almost ready to be harvested. When over half of your onion leaves look as though they have fallen over it is time to fold the others over as well. 

From there you can lessen watering and wait for the time to harvest. 

Fertilizer For Onions

When it comes to fertilizer for onions your main concern should always be sulphur. This means using manure or manure-based fertilizer is ideal. Sulphur is one of the nutrients that onions have a high affinity for. The other basic nutrients such as NP & K are all used within regular quantities. You can use an all-purpose fertilizer with onions and follow the directions on the package.

In an ideal world, you will find a fertilizer that also includes sulphur. This fertilizer will have four numbers on the number area. It will be nitrogen, potassium, phosphorus, sulphur (N-P-K-S). 

There you have a complete guide to growing onions in Canada. If you’re debating growing some onions or scallions in Canada then this is the perfect guide for you. If you’re ever looking for more content be sure to check out Kearney Canada on Instagram, Facebook, YouTube, and almost any other social media platform.

Growing Onions in canda
growing onions in canada