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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Forcing Spring-Flowering Bulbs Indoors

This article was published originally on 9/14/2011

Tulips, daffodils, hyacinths, and crocuses are a welcome sight in spring. Gardeners can also enjoy these spring-flowering bulbs during the winter months by forcing them indoors. 
 
To enjoy spring-flowering bulbs in winter, gardeners must begin the forcing process in late summer or early fall. Gardeners need good quality bulbs, a well-drained potting mix, and containers with drainage holes in the bottom. 
 
Begin by partially filling the container (pot) with potting soil. Then place the bulbs on the soil surface. Adjust the soil level until the tops of the bulbs are even with or slightly below the rim of the container. The number of bulbs to plant per pot depends on the size of the bulb and container.
 
Generally, 3 hyacinths, 3 to 5 daffodils, 5 to 7 tulips, and 10 to 12 crocuses can be planted in a 6-inch-diameter pot. After arranging the bulbs in the pot, place additional potting soil around the bulbs. However, don't cover the bulbs completely. Allow the tops (noses) of the bulbs to stick above the potting soil. After potting, water each container thoroughly. 
 
In order to bloom, spring-flowering bulbs must be exposed to temperatures of 40 to 45 degrees Fahrenheit for 12 to 16 weeks.  Possible storage sites include the refrigerator, root cellar, or an outdoor trench. When using the refrigerator for cold storage, place the potted bulbs in a plastic bag if the refrigerator contains apples or other ripening fruit. Ripening fruit give off ethylene gas that may impair flower development. During cold storage, water the bulbs regularly and keep them in complete darkness. 
 
Once the cold requirement has been met, begin to remove the potted bulbs from cold storage. Place the bulbs in a cool (50 to 60 degree Fahrenheit) location that receives low to medium light. When the bulbs begin to grow, move the plants to a slightly warmer area that receives bright light. Keep the potting soil evenly moist during the forcing period. Flowering should occur in 3 to 4 weeks. For a succession of bloom, remove pots from cold storage at 10 to 14 day intervals.