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How to Grow Ranunculus From Seed

Ranunculus produce stunning flowers that resemble old-fashioned cabbage roses. They come in colors ranging from white to purple to pink and each plant produces dozens of blooms during the growing season. Ranunculus are most often grown from small bulbets, but they produce seed and it is possible to grow them from seed. Start the seeds indoors about 12 weeks before the average date of your last spring frost. The small plants can be transplanted outdoors when daytime temperatures are reliably in the 50s.

Secure a seed starting stand with the ability to hang the fluorescent lights above the seedlings and raise and lower the height of the lights.

Fill 2-inch starter pots with seed starting mix. Smooth the top of the soil.

Sprinkle ranunculus seed generously on top of the growing mix. The seeds of this flower have a low germination rate so plant a large number of seeds. Sprinkle a thin layer of the seed starting mix on top of the seeds. Gently firm the top of the soil with your hand.

Place the 2-inch starter pots into a large shallow container. Add water to the large container until it is half way up the sides of the 2-inch pots. Let them sit in the water until the surface of the seed starting mix looks damp. Remove 2-inch pots from the water and allow them to drain thoroughly. Water using this method until the seedlings are 2- to 3-inches high.

Place the pots under the fluorescent lights so the top of the pot is about 4 inches from the bulb. Keep the pots at a temperature of 50 degrees Fahrenheit until they germinate in about 20 to 30 days.

Thin when the seedlings are about 2 inches high. Use the tip of a scissors and snip off all but the strongest plant in each 2-inch pot. Cut off the unwanted seedlings at soil level.

Raise the height of the lights as the seedlings grow to maintain a distance of about 3 to 4 inches between the tops of the plants and the light bulbs. Keep the lights on for 14 to 16 hours a day.

Begin to harden off the seedlings when daytime temperatures are in the upper 40s. Put the small ranunculus plants outdoors in the shade for a longer period each day until they are outdoors all day long. After that, move the pots into full sunlight for a longer period each day until they are in full sunlight all the time. Bring plants indoors at night or anytime frost threatens.

Plant in the garden in a location that has full sun and very well-drained soil. Space the transplants about 8- to 12-inches apart in regular, unimproved garden soil.

Water the transplants as you plant them using a hand watering can. Continue to provide ranunculus with the equivalent of 1 inch of rainfall per week.

Fertilize weekly with a water soluble fertilizer applied to individual plants with a hand watering can. Use a mixture that is half the manufacturer’s recommended rate of application.

Mulch the soil in the garden bed with 2 to 4 nches of organic mulch, such as buckwheat hulls or shredded bark. Ranunculus are cool-weather perennials and prefer their roots cool but not soggy.

Mulch the roots in late fall after the foliage has died down for the winter. Put down a 6- to 12-inch layer of hay or straw to protect the roots from freezing winter temperatures.

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