Wednesday, September 21, 2011

Force bulbs in fall to bloom indoors in winter

By David Burton
University Extension

To add a bit of color to the dull days of winter plant lovers might consider starting a process known as “forcing bulbs” this fall.

According to Patrick Byers, a horticulture specialist with University of Missouri Extension, it is possible to get bulbs (like daffodils, hyacinths, tulips, crocus) to bloom indoors during January, February or March.

“Spring bulbs have a chilling requirement which must be met before they will flower indoors so that is why you need to plan ahead,” said Byers.

“Forced bulbs” are those which are induced to flower at something other than their normal time.

The process is relatively simple and involves five basic stages or steps.

Byers says to start with healthy bulbs, a soilless medium that is well drained, and some pots.

Use azalea or bulb pots four to eight inches in diameter. Put several bulbs, of the same variety, in to the pot and then cover them with the soilless medium. Different bulbs have different depth requirements, but generally a portion of the bulb will either be above the soil or no more than one inch below the soil.

“Loose pack the pot, water the bulbs, and then find a way to expose them to cool temperatures (between 35 and 40 degrees Fahrenheit) for about 13 weeks,” said Byers.

These temperatures might be achieved in a cool north room, basement, bulb cellar, outdoor trench, cold frame or refrigerator. If a refrigerator is used, food products should not be stored in the refrigerator while the bulbs are being chilled.

“The purpose of the chilling stage is to allow bulbs to produce a healthy root system and to elongate their flower primordium in advance of being forced to bloom,” said Byers.

The actual forcing of the blooms can take an additional three to four weeks. Put the pots in a bright window where temperatures are around 60 degrees.

“When flower buds are almost fully developed, pots may be moved out of the bright window into the living room or other area of the home so they can be displayed and enjoyed,” said Byers.