What You Will Need
Top-quality ranunculus corms
- Potting soil or peat moss
- Organic fertilizer
- Frost cloth
- Drip irrigation or soaker hoses
- Depending on where you live and what kind of set-up you're working with, you can plant your ranunculus in either the fall or late winter/early spring. While spring-planted corms won't be quite as prolific as fall-planted ones, a nice harvest can still be had. In areas with mild winter temps (zone 7 and above) ranunculus can be planted in the fall and successfully overwintered outdoors with minimal protection, such as a low tunnel or frost cloth. In colder areas, where temps dip well below freezing for extended periods of time, you can start them indoors—in a hoophouse or low tunnel, or in trays to plant out later—at the very end of winter. Plants can be moved outside once the threat of deep freezing has passed; this is usually about a month before your last spring frost.
- When you unpack your ranunculus corms, you'll see that they resemble little brown octopuses. This probably is not what you were expecting. Don't worry, these strange-looking creatures will actually produce an abundance of beautiful, ruffled blooms!
- Before planting, soak corms for 3 to 4 hours in room-temperature water, leaving the water running just slightly during the process to help provide extra oxygen. As the corms soak, they will plump up, often doubling in size. After soaking, corms can either be planted directly into the ground, or they can be presprouted. Presprouting the corms before planting will give plants a jumpstart, and you'll have flowers a few weeks earlier than you would with non-presprouted ones.
- To presprout, fill a flat-bottom seed tray half full of moist potting soil. Sprinkle the soaked corms into the soil and cover them with more soil so that they are completely covered. Leave this tray in a cool place (40-50°F or 4-10°C), where rodents can't find it, for 10 to 14 days. Check on the corms every few days, make sure the soil is moist but not soggy, and remove any corms that show signs of rot or mold.
- During this time, corms will swell to twice their original size and develop little white rootlets that resemble hair. Once these roots are about 1/8- to 1/2-inch (0.3-1 cm) long—pull them up to check—it's time to plant them in the ground. Before planting, it's important to prepare the growing beds. We add a generous dose of compost (2-3 inches or 5-7.5 cm) and balanced organic fertilizer (we use Nature's Intent 7-2-4) and mix it thoroughly into the soil. Corms are planted 9 inches (15 cm) apart at a depth of 2-3 inches (5-7.5 cm) with 4 rows per bed with the "octopus tentacles" pointing down.
- During cold stretches, when temps dip below freezing, cover the plants with a layer of frost cloth.
- Ranunculus normally starts to flower about 90 days after planting. Fall-planted corms bloom in early spring and continue steadily for six to seven weeks. Late winter-planted corms will flower by mid-spring and continue for four to six weeks.
- The vase life of ranunculus is outstanding, often exceeding 10 days. For the longest vase life, cut when buds are colored and squishy, like a marshmallow, but not open. If cut when flowers are open, they still last a good week but are more fragile to transport.