How to Grow Sweet Peas in a Cold Climate

Sweet peas are a flower that brings fond memories of summers spent in grandma’s garden, and the smell of sweet peas is so nostalgic that everyone needs to plant just a few in their garden. Despite these warm fuzzy memories, and even though I’ve been told time and time again that they are easy flowers, I don’t really like sweet peas because I’ve found them difficult to grow.

As a cold-climate gardener, I could never understand how something that should be direct sown after the last frost could also magically bloom in June. I never saw any blooms until August! And even after pre-soaking my sweet pea seeds, I didn’t see very much success.

Little did I know I was doing everything wrong.

When I finally learned the secret to growing good sweet peas, I was overjoyed. And it really was pretty simple! If you’ve struggled with growing these fragrant flowers in your short growing season in the past, read on for my secret to growing succesful sweet peas!

A person wearing a pink top and beige shorts is holding a single stem with a small pink flower. The person is outside, with green foliage in the blurred background. The focus is on the person's hand and the flower.

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the Do’s and don’ts of growing sweet peas in zone 3

Don’t start your sweet peas on your last frost date if you have a short growing season! This may seem counterintuitive, but I garden on the Saskatchewan prairies in Zone 3 and have found the best time to start them is as soon as the snow melts and the soil can be worked (read: the ground should not be mud).
Sweet peas can withstand temperatures as low as -5°C/23°C. If you’re worried about them, you can cover them with frost fabric, though I can confirm that they do withstand -5°C because I had a bit of a situation last year.
There’s no need to pre-soak sweet pea seeds. You don’t have to scarify them either. While you can, it’s not necessary.
Sweet peas should be pinched. Once I started pinching my sweet peas, I had so much more success. They come back, and then there are more of them to enjoy!
Pick sweet peas for your own enjoyment! Many people are scared to do this because they think they won’t come back, but they are cut and come again, so you don’t need to worry so much about this.
Let some of your sweet peas go to seed to save them for next year. Specialty sweet pea varieties can be quite expensive, so this is a good trick to save some money!

NOTE: Please be cautious planting sweet peas if you have pets. They are highly toxic to cats, dogs, horses, and other animals, so plant with caution and do your research before planting them in an easily accessible area of your garden!

A close-up of a delicate purple flower with a green stem, set against a blurred background of a garden with green foliage and subtle hints of orange flowers. The soft light and bokeh effect create a serene and peaceful atmosphere.

best practice for planting sweet peas

Growing sweet peas in your cut flower garden is as easy as 1, 2, 3…

Start your sweet peas between March 1st and March 31st
Plant them out as soon as the soil can be worked — no need to pre-soak
If you start them indoors, keep pinching them so they don’t get too tall!

P.S. I’m growing this variety as part of my 2024 beginner-friendly $100 cut flower garden. Check out the details here!

FAQ’s About Growing Sweet Peas

What is the best way to germinate sweet peas?

I don’t normally do anything that fancy. I just put the seeds in the soil and pop them under grow lights, and they do just fine! If you’re really worried, try the window seed starting towel trick.

Grab a paper towel and soak it with water. Then spread your seeds on the damp paper towel and fold it to fit inside a plastic bag. Zip the bag up and tape it to a south-facing window. Then, wait for the seeds to germinate!

How much sun do sweet peas need?

You can get away with planting sweet peas in part shade but don’t expect tall stems if you do. Sweet peas love the sun, so if you can find a sunny corner in your flower garden, they will be all the happier!

A colorful cluster of sweet pea flowers in shades of pink, purple, and white grows vibrantly in a garden. A fence and trees are softly blurred in the background, with the warm light of the setting sun filtering through.

Have any other questions you’d like answered? Let me know, and I’ll add them to this post!

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WANT A CUT FLOWER GARDEN WITHOUT THE HASSLE?

If you need more help with your cut flower garden and putting everything together, you’ll love Cut Flowers Made Simple. It’s the cheapest and easiest way to start a cut flower garden in your backyard or use it as a way to dip your toes into flower farming.