Ranunculus are some of the most stunning spring flowers, often compared to roses and peonies for their layers of silky petals. Their ruffles are something you just can't take your eyes off. If you’ve ever admired their delicate, vibrant blooms at a flower shop or store and wondered if you could grow them yourself, the answer is yes! And the secret lies in starting with ranunculus corms.
Whether you’re a backyard gardener or an aspiring flower farmer, this guide will walk you through exactly how to grow ranunculus from corms, step by step. I've been using these steps for years, and they have yet to let me down!
What Are Ranunculus Corms?
Before planting, it helps to understand what you’re working with. A corm is essentially a bulb-like storage organ that holds all the energy your ranunculus needs to sprout and bloom. They look like strange little brown octopuses and need a bit of prep before planting.
Step 1: Soak the Corms
To wake up your ranunculus corms, start by soaking them in cool water for 3–4 hours. This helps them plump up and speeds up germination.
- Use a bowl or bucket of clean water
- Stir the water every hour to keep it oxygenated (or not but it does help!)
- Do not soak longer than 4 hours, or they may rot
Step 2: Pre-Sprout (Optional but Recommended)
For stronger plants and earlier blooms, pre-sprouting is highly recommended. Especially if you live in a hot climate!
- Fill a shallow tray with damp potting soil or vermiculite
- Place the soaked corms into the medium tentacles down
- Store in a cool, dark place (40–50°F) for 1–2 weeks
- Check regularly—once you see tiny rootlets, they’re ready to plant
Step 3: Choose the Right Location
Ranunculus love cool weather and thrive in full sun with well-draining soil.
- Best soil pH: 6.0–6.5
- Add compost to give your soil a boost and feed the ranunculus
- Raised beds or fabric pots are great options if your soil is heavy or you expect a lot of rain in your area
Step 4: Planting the Corms
Your corms are ready once you see growth. You can plant once you see roots or let them grow out a little in small pots before transplanting.
- Dig holes 2 inches deep and 6-8 inches apart to give them adequate airflow
- Place the corm tentacle-side down (the little “legs” facing the soil)
- Cover with soil and water lightly
Pro tip: Stagger planting times every few weeks for a longer blooming season
Step 5: Watering and Care
- Watering: Keep soil moist but never soggy
- Fertilizer: Feed with a balanced liquid fertilizer as needed once growth appears
- Temperature: Ranunculus prefer cool nights (40–50°F) and mild days (55–65°F)
Step 6: Harvesting Your Ranunculus
For cut flowers, harvest when buds are marshmallow stage—not fully open, but soft and slightly squishy. This ensures the longest vase life.
- Cut in the morning when blooms are hydrated
- Place stems directly in cool water
- Ranunculus can last 7–10 days in a vase with proper care
- Keep away from fruit, extreme temperatures, and direct sunlight
Common Mistakes to Avoid
- Overwatering: Causes corm rot
- Planting too deep: May delay or prevent sprouting
- Hot weather planting: Ranunculus won’t thrive in summer heat; plant in fall (zones 8–10) or early spring (zones 4–7)
- Too close together: Ranunculus is susceptible to fungus so make sure to give them enough space and airflow
Final Thoughts
Growing ranunculus from corms may sound intimidating, but once you understand the process, it’s surprisingly easy and incredibly rewarding. With just a little prep, you’ll be rewarded with armloads of lush, colorful blooms perfect for bouquets or simply enjoying in your garden.
