Ranunculus Cut Flower Production in Utah Shannon Rauter and Melanie Stock Ranunculus (Ranunculus asiaticus) is grown as a coolseason annual for cut flower production in Utah. Tuberous roots can be planted as early as November in a high tunnel for blooms beginning in April. For field production, plant in November with insulation or as early as possible in spring for blooms beginning in May. Flower production ceases when temperatures reach approximately 80°F, usually by early July in northern Utah. In North Logan, UT, high tunnels produced an average of 3 to 7 marketable stems per plant, compared to 1 to 2 stems per plant in the field. Ranunculus is popular in weddings and spring arrangements. Profit potential is high when grown in a high tunnel and sold wholesale compared to other Utah-grown cut flowers.
Tuberous Root Preparation
Order tuberous roots (also often called corms) in spring to summer for fall delivery. Purchase the largest tuberous root size available (usually 5-7 cm), as size is directly linked to yield. Yields typically range from 3 to 6 stems per plant but up to 12 stems per plant may be possible with proper management. Tuberous roots that are not immediately planted should be stored in cool (35-50°F), dry conditions to reduce the risk of rot.
Site Preparation
For ranunculus grown in high tunnels (Figure 1), planning and preparation begin the previous fall by installing the plastic high tunnel covering before heavy rain or snowfall. This ensures the soil will have the right moisture content for workability early the following spring and decreases the risk of disease. Careful use of soil amendments (i.e., fertilizer, compost, manure) is necessary because ranunculus is sensitive to soil salinity, with stress occurring by 2.5 dS per m. Soil test to determine nutrient needs in new planting areas and repeat every two years. USU’s analytical laboratory performs soil tests and instructions for sampling can be found here. Incorporate fertilizer or compost based on routine soil test recommendations. Tilling one inch of low-salt compost into the soil before planting increases organic matter and fertility, with minimal pH or salinity risk. See USU’s Compost and Manure Guidelines for options. Rake the tilled soil smooth and form beds that are 3 to 4 feet wide. Wider beds make it difficult to reach the center rows. Install drip irrigation and landscape fabric, if desired, before planting.
Figure 1. Aim to harvest at or soon after the bloom stage of the stem in the center, as the bloom on the bottom left is too tightly closed and the bloom on the top right is too open.
Soaking and Pre-sprouting
Before planting, tuberous roots benefit from soaking in room temperature water (60 to 77°F) for 3 hours.
Utah State University Extension | April 2023 | Peer-Reviewed Fact Sheet | CutFlower/01
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