Ranunculus is a cannot-miss spring flower. They have incredible vase life, resemble a peony or a rose with their countless petals, and can bloom throughout spring.
Ranunculus require more fussing than tulips or daffodils, but when they bloom it’s spectacular. Plus, they will likely bloom multiple times in the spring, meaning you’ll get waves of flowers rather than a one-and-done, like a tulip.
I’ve been growing them for a few years now and I have had successes and failures.
Despite the failures, I’m hooked.
Here’s how I grow ranunculus in Seattle (zone 8b/9a):
When to plant:
In Seattle, you can plant ranunculus anytime from October to early March.
Ranunculus benefit from cold stratification—which means they grow better when they experience several weeks of cool weather before blooming. The earlier you plant them, the earlier they bloom and the more they’ll bloom during the spring.
They can survive temps down to 25 degrees for short periods. Fortunately, Seattle winters rarely get that cold, and when they do, it’s brief. Since the ground almost-never freezes, you can plant them and let them do their thing.
I use row cover and leaves/mulch for extra warmth when temps drop below freezing for extended periods. If ranunculus corms are exposed to prolonged freezing temps, they’ll freeze and rot.
This year (2025,) I started presprouting ranunculus in October and have been starting a new batch every other week since then. I’m planning to presprout a new tray weekly through January in hopes of multiple waves of blooms this spring.
When you buy corms, you’re purchasing dehydrated roots (they look like calamari) that need to be soaked before planting.
If possible, buy the largest corms you can. Bigger corms = more blooms and better rot resistance.
There are many varieties of ranunculus in different shapes and colors. More expensive corms are larger, produce more blooms, and are more disease-resistant. But cheaper varieties grow great too—don’t let price intimidate you.
Soaking (recommended):
Soak your corms in room temperature water for 3 to 4 hours. Don’t over-soak or they’ll rot.
This hydrates the corms and helps them germinate faster and more reliably.
I set a timer for three hours, knowing full well I’ll lollygag before actually pulling them out and getting them into dirt.
I do NOT change the water every hour or keep it flowing with a sous vide or aquarium pump like some people on the Internet claim you need to. Life is too short. My husband would also kill me if I used our sous vide in the kitchen for gardening. (He instituted a strict no-kitchen-items-shall-be-co-mingled-with-anything-gardening-related policy after past incidents.)
Presprouting (I do this, but it’s not required):
I prefer to presprout my ranunculus indoors because they’re less likely to rot or get stolen by a rat. (Excuse me while I vomit at the thought.)
Not everyone does this and it’s not necessary, but I’ve had much higher success rates with presprouting indoors.
Here’s how:
Fill a flat-bottom seed tray (plastic fruit packaging or reusable takeout containers work too) with moist potting soil—about half an inch to an inch deep.
If the potting soil comes out of the bag moist, I put the corms right in. If it’s dry, I use a spray bottle to moisten it.
Place the ranunculus corms on the soil, tentacles down, then completely cover them with more soil—an inch or two is sufficient.
Put them in a room that’s between 50 and 65 degrees for about two to three weeks. (If it's a little colder or a little warmer, they'll be fine.)
Check on them at least once a week to ensure the soil stays slightly moist (but not wet!) and none of the corms are rotting. I’ve murdered enough ranunculus with too-wet potting soil to know that corms prefer slightly moist, not damp, soil.
When the corms sprout white roots after two weeks, they’re ready for planting.
Do you need to presprout?
No. Plenty of growers skip this step.
But I do it because: (1) I’m paranoid about rot in our wet winters, and (2) rats are less likely to steal presprouted corms. My success rate is way higher when I presprout indoors.
If you don’t presprout, plant your corms immediately after soaking them for a few hours.
Tips for planting:
- Plant them with the tentacles down.
- Plant them 6-to-9 inches apart (I always plant 6 inches apart) and 1-to-2 inches under the surface.
- Add compost and a well balanced fertilizer when planting. (I top off my growing area area with an inch or two of Cedar Grow compost from Burien Bark, and mix in a well balanced fertilizer when I plant.)
- I also utilize low-row cover to give them some extra protection during cold weather. Read more about it here.
End of season ranunculus care:
Ranunculus corms go dormant when the weather gets too hot, which happens in Seattle around June.
If you want to dig them up and store them to replant next season, wait for the foliage to naturally die back. Then dig them up, dry them, and store them in a dark, cool area until you’re ready to replant.
In the Seattle area, you may be able to leave them in the ground and never dig them up. Corms are very susceptible to rot, so turn off any irrigation during summer. (Full disclosure: I’ve never attempted this.)
Saving corms for the following year:
You can treat ranunculus corms as annuals; however, there is a way to save the corms for the following year. (I haven’t tried this before, but I’ve heard other people have success with it.)
Helpful links if you want to learn more:
👉 Ranunculus corms for sale (use discount code TURD to take 25 percent off all ranunculus corms this January.)
👉 Curious as to why the discount code is TURD? Read about it here.
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