Ranunculus corms


I’ve been gifted ranunculus corms and it’s March 30. Can I just pre-soak them for 3 to 4 hours and shove them in the ground. Do I wait a week or two? Is it all too late for this year? I’ve never planted them before. I appreciate your help!


Lucky you!  Don’t worry, it’s not too late to plant the corms.

You are not the first one to ask us this question.  Here’s response published previously on our website (where the corms are referred to as tubers):

Ask a Master Gardener. Ranunculus.

To summarize, you can either

  • pot the corms now – put them in a spot where they get full sun during the day then cool temperatures at night. When frost is no longer a concern (around May 9 in the GTA, could be earlier or later, though) and the plants have their first leaves, transplant them outdoors (acclimatize them to the outdoors first); or
  • wait and plant the corms outside in late spring, when all danger of frost has passed.

Outdoors, make select a spot that receives full sun and has rich soil that drains well, or plant them in a container.

To prepare the corms for planting, soak them for up to 3-4 hours (no longer or they could rot).  Corms look like small claws – plant them with the “claws” facing downward around 5 cm (2 inches) deep, and 23 cm (9 inches) apart (in containers you can plant them 15 cm (6 inches) apart).  They should bloom 90 days or so after you plant them.

Longfield Gardens’10 Tips for Growing Ranunculus  provides detailed information about soaking and pre-sprouting the corms, which is another option you may consider.

The plants are hardy to growing zones 8-10, so treat them as an annual – they won’t survive GTA winters unless you bring the corms in to store over-winter or grow them under a floating row cover or in a greenhouse.