Plant indoor flowers now to enjoy in winterMany gardeners purchased tulip and crocus bulbs with good intentions of planting them this fall. Unfortunately, they often run out of time before getting the bulbs in the ground. Because the bulbs can’t be stored for the winter and then planted in spring, it is best to use unplanted bulbs for forcing. Forcing refers to a process by which plants, typically spring bulbs, are “tricked” into blooming indoors at a time other than their natural blooming season.
By: Sandy Eckelberg, The Jamestown Sun
Many gardeners purchased tulip and crocus bulbs with good intentions of planting them this fall. Unfortunately, they often run out of time before getting the bulbs in the ground. Because the bulbs can’t be stored for the winter and then planted in spring, it is best to use unplanted bulbs for forcing. Forcing refers to a process by which plants, typically spring bulbs, are “tricked” into blooming indoors at a time other than their natural blooming season.
Because bulbs contain all the nutrients they need to grow and bloom, gardeners merely need to provide proper growing conditions. Temperature is the most important requirement. Bulbs need cold conditioning to trigger chemical reactions needed to initiate blooming. By providing bulbs with artificial conditions their biological clocks can be altered, allowing them to bloom at a desired time.
The forcing process takes eight to 12 weeks from planting to blooming depending bulb type. By planting the bulbs at weekly intervals you can enjoy blooming plants for several weeks in the winter. To force bulbs you will need bulbs, sand or pea gravel, pots, potting soil and a cool storage area.
When selecting bulbs for forcing, choose those that are labeled as being dwarf or less than 10 inches tall. Pick bulbs that are firm, showing no signs of decay. Some bulbs may be labeled as being “precooled.” These bulbs do not require a cold treatment. Bulbs that work well for forcing include dwarf tulips and daffodils, hyacinths, scillia and grape hyacinth.
Containers can be any shape or size as long as they have drainholes. They do not need to be deep. In fact, traditional bulb pans are only about 4 inches deep. They can be ceramic, terra cotta or plastic.
Put a layer of pea gravel or coarse sand in the bottom of the container then add a thin layer of potting soil. A light, loose potting soil is best for forcing bulbs. It should contain some peat moss along with perlite or vermiculite for drainage. After adding a thin layer of potting soil, place bulbs in the container, allowing a slight gap between each bulb. Finish by completely covering bulbs with more potting soil.
Water pots several times to thoroughly moisten the medium. The bulbs are now ready to be cooled. Bulbs need to be provided with a simulated version of winter in order to initiate flower buds. The ideal temperatures for chilling are between 35 and 50 degrees Fahrenheit. A root cellar provides a perfect place for chilling bulbs. A basement or garage can be used provided they do not become too warm or too cold. Pots can be covered with straw, newspapers or old blankets to help insulate them against cold temperatures. If there’s space, pots can be chilled in the refrigerator.
Pots should be placed in plastic bags to help retain humidity. Cut a few slits in the bag to allow air circulation. When using a refrigerator, bulbs should be cooled gradually by lowering the thermostat in stages until the temperature reaches 35 to 40 degrees. Never store fruit or vegetables in a refrigerator that is being used to force bulbs.
It may seem like nothing is happening during the cooling period but the bulbs are busy growing roots. Check the moisture level in the pots occasionally and water as needed, they should not be soggy nor should they be allowed to dry out. After several weeks new shoots will emerge. When shoots are an inch or two tall the plants are ready to be moved into a window that receives direct sunlight. The bulbs still require cool temperatures, around 50- 60 degrees. Turn pots regularly to prevent uneven growth. Fertilize bulbs, except hyacinth, weekly with a diluted solution of a water soluble fertilizer.
The plants will continue to grow and should develop flower buds in a few weeks. Once they begin to bloom, the plants can be moved into an area where they can be enjoyed. Keep them away from direct heat and continue to provide plenty of sunlight. Moving the pots back to the cool room at night will prolong the life of the blooms.
If you purchased bulbs but didn’t get them planted, consider forcing them for indoor blooms. The bulbs won’t go to waste and you’ll be rewarded with beautiful winter blooms.