Updated: Feb 5, 2021
Ranuncs (as they’re know to flower farmers) are little flower machines. They’re not as easy to grow as tulips and daffodils, but they’re more productive. They grow from corms, which function like bulbs but are smaller and shaped differently. Ranunc corms look like tiny octopuses, so they might be fun to show a child. You can buy them in nurseries in the fall or order them online starting in summer.
Although you can simply plant them in the ground straight from the bag they come in, you’ll have better luck of you take the time to pre-sprout them. Pre-sprouting gives them a significant advantage in development and bloom time. To presprout corms, you first prepare some potting soil or seed starting mix by getting it thoroughly damp. You can buy good seed starting mix at the nursery and it works well for this process, but you need to wet it for half a day at least because it doesn’t take up water easily. When it’s ready, spread a layer of it in a tray, about an inch deep.
When the soil is ready, soak the corms, in mesh bags, for about three hours in cool water. Often the corms come in mesh bags, but if not, use panty hose or anything similar that will keep them together while allowing water to flow through and around. Keep a slow drip from the faucet so there’s good aeration. After three or four hours the corms have plumped a bit and they’re ready to go into the trays of soil. Take the corms out and gently place them in the tray of soil, arms down. Be careful not to break off the little arms. Spacing the corms about a half-inch or an inch apart, them cover them with an inch of potting soil. Put them somewhere dark and cool. I use our unheated garage. Check the soil every day or two to make sure it stays damp. After seven to ten days, check what’s going on—you’ll likely find that there are tiny roots and sprouts forming.
Now you can plant the baby ranuncs outside. Plant them about 6-9” apart and about 2” deep. Make sure they’ll get sun. Now go watch some movies, read a book or generally get on with your life. Water the ranunc bed if there’s no rain, but don’t go overboard. Soon the green plants will emerge, and after another few weeks you’ll see buds, and soon after that – flowers! Congratulations, you’ve grown beautiful ranunculus!