ASK THE MASTER GARDENERS
Q: I would like to try to force some bulbs this fall and winter. Which varieties work well, and how cold does the space for forcing need to be?
A: November is a great time to start the forcing process. Choose large healthy bulbs without sprouted roots. These may be purchased pre-chilled (a bit more expensive) or you may chill them at home. Each group of bulbs has a different chilling requirement and blooming time. Pre-chilled bulbs left in warm indoor temperatures will break dormancy and begin to go into flower.
A refrigerator can supply the 35- to 45-degree temperature range required to force most bulbs. It is mandatory that bulbs be isolated from fruits or ripening vegetables as they are chilled; these produce ethylene gas that negatively affects flowering.
You can also use areas like an unheated part of your basement or garage for forcing. Just make sure it’s a spot where temperatures never dip below freezing.
Bulbs may be potted before or after chilling. Here’s a look at how long a few popular bulbs need to go into cold storage. For all of these, the blossoms will begin to appear two to three weeks after planting, or removing them from cold storage.
Narcissus/daffodil: 12 to 15 weeks of chilling.
Hyacinth: 12 to 15 weeks.
Tulip: 10 to 16 weeks.
Crocus: 8 to 15 weeks.
It is OK to chill the bulbs longer, as you are simulating winter. Once out of the cold the bulbs start the journey to bloom.
Collect potting soil and wide pots, preferably three times the depth of the largest bulbs to be potted), and labels to identify the bulbs. Fill the pot two-thirds with soil and place bulbs next to each other, pressing them lightly into the soil. Place as many bulbs in the center of the pot as it can hold, leaving 1 inch of space around the rim. Fill in this space with potting soil and press lightly to firm the mix, and water well. Place a label in the pot and move it into a cool room until the shoots begin to turn green.
Or you can pot up unchilled bulbs now, as directed above, and move the pot into cold storage for the recommended number of weeks.
Once you are familiar with the cooling and potting process, you may combine different bulbs in the same pot to create your own attractive design. For more information on growing bulbs, contact your local Cooperative Extension.
Krys Mernyk, master gardener with Cornell Cooperative Extension of Westchester