How to Grow Ranunculus in Zone 3 (So it doesn't die!) | Shifting Roots

How to Grow Ranunculus in Zone 3 (So it doesn’t die!)

If you’re growing cut flowers in your garden and hoping for some earlier spring blooms, you’ll quickly realize that there aren’t a lot of options for those of us in short growing seasons with cool climates. Enter the ranunculus. It looks like a garden rose and brings a welcome hit of colour in Spring bouquets, and it’s something less expected than the standard daffodils, tulips, and lilacs.

Plus, ranunculus can withstand temperatures up to minus 5 degrees celcius–a huge win!

The downside? Growing ranunculus requires a few extra steps and fussing that beginner gardeners might not be prepared for. These finicky flowers took me a few years to get the hang of, but now that I’ve made a bunch of mistakes, you don’t have to.

Here’s 3 easy steps to grow ranunculus so they don’t die.

pink and white ranunculus flowers

1. Soak the Corms

The first year I failed at growing ranunculus, it was largely because I didn’t realize you had to soak the corms first. My dried out little corms never stood a chance.

Soak for 6 hours, and up to 24 before planting. 6 hours is ideal, and any more than 24 and your corms might start turning to mush.

soaked ranunculus corm ready for potting.

The second year I tried ranunculus, I soaked them, but kept forgetting about them, drying them out, and rehydrating them. It was a mess and I don’t know what I was thinking, but I know that I was 7 months pregnant, super tired, and the world was going crazy because it was March of 2020. So I cut myself some slack, and thankfully some of those corms were tough and handled my abuse.

2. Start Indoors

Ranunculus need around 90 days for maturity, so technically, I could put them directly outdoors in May when I plant the rest of my garden. However, this is a bad idea because they would then be blooming in the warmest part of the year–not ideal for a cool-loving flower.

ranunculus greens poking through the soil.

I start mine in early March for blooms in June. This is about the earliest I can start them considering the temperatures they need and my lack of a greenhouse.

3. Harden off with a Hoop House for Best Results

However, I do have a small hoop house my husband made me that let’s me put them outdoors with some confidence. I have a few garden bricks to pop up the house on hot days, and so they can slowly get acclimatized to the wind.

In fact, I now harden off almost all of my flowers this way because it works so well.

Ranunculus seedlings in a hoop house grown in zone 3, Saskatoon SK

When is the Best Time to Start Ranunculus?

March 6th. Kidding. . . sort of. If you want blooms in June, you need to start in early March. You can technically start ranunculus anytime as long as you have 90 days for it to grow. However, it doesn’t really like the heat, so starting on the optimal planting day in May for everything else meant that your blooms may not do as well in the late summer heat.

Can you Grow Ranunculus in Containers?

Yes! And in a way, it’s actually better that you do. The first year I tried ranunculus, part of the reason I failed was that I planted them in a flower bed that had a lot of competition from weeds and nonsense perennials. The soil mix in containers means you’ll get better results.

Last year (2020) I devoted a raised bed to them and I got great results. So whether you’re planting in ground, in containers, or as part of a square foot garden, it can work.

How do you Store Ranunculus Corms?

In short, the process is similar to how you save and store dahlia tubers. Once they’ve died back and yellowed, carefully pull the corm back and gently remove excess soil. Let them dry in the sun, then try and remove more excess soil. Store in a box with peat moss over the winter in a cool, dry, and dark place.

I hope you feel inspired to try growing some ranunculus this spring! 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.

Learn more here.

Kristen Raney

Kristen Raney

Kristen is a former farm kid turned urban gardener who owns the popular gardening website, Shifting Roots.  She is obsessed with growing flowers and pushing the limits of what can be grown in her zone 3b garden.  She also loves to grow tomatoes, but oddly enough, dislikes eating them raw.

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Hi, I'm Kristen and I help new gardeners learn to grow their own vegetables and beautify their yards. I also share recipes that use all that delicious garden produce. Grab a coffee (and your gardening gloves) and join me for gardening tips, simple recipes, and the occasional DIY, all from the lovely city of Saskatoon, Saskatchewan.

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