Forcing Bulbs for Winter Color

Forcing bulbs: There is no quicker way to bring spring indoors during the winter than with a pot of bulbs. Many different bulbs can be forced, including tulips, hardy narcissus, hyacinths, squill, and crocuses. These are all hardy bulbs that need a 15-week prerooting period before they can be brought into active growth. That period of enforced cold convinces them that winter is at hand; when they’re brought to a warm spot, they assume that spring has arrived and they bloom.

To begin the process usually several bulbs are potted together in a 6-inch bulb pan. Hyacinths, which are large-flowered, look handsome planted as singles in regular 4-inch flowerpots. Add a dusting of a good natural fertilizer like Bulb Tone by Espoma to the soil so the bulbs will have additional nutrients. When they’re planted in the pots, the tips of the bulbs should peek just above the soil line, which should itself be about ½ inch below the rim of the pot. Then moisten the soil and the bulbs are ready for winter.

There are several different ways to store winter bulbs; the purpose is simply to keep the bulbs at 40 degrees or so. Also they can’t be allowed to dry out or freeze. A bulkhead, cool cellar, or refrigerator is fine. Also a cold frame or a bulb trench dug outdoors can be used. After 15 weeks, the first of the bulbs can be brought indoors. Plan on bringing in just a pot or two at a time to give you a sequence of flowering plants through most of the late winter and early spring. Put the pots on a bright but cool windowsill until the shoots are about 4” tall. Then move them into bright sunlight until the flower buds start to show color, at which point move them back into bright indirect light. While bulb plants are growing and in flower, they do best with night temperatures in the low 40s at night and the 60s in the day. Keep the soil moist but don’t feed them. Then enjoy an early taste of spring.

When the bulb plant’s leaves begin to turn yellow, reduce the amount of water and give them only enough to keep the leaves from wilting. By the time the leaves have withered entirely, the soil should be dry. The bulbs can be stored in their pots until the fall, or they can be taken from their pots and stored in a cool dry place. Most bulb plants can’t be forced a second time. But if you have an outdoor garden, you can save the bulbs and plant them outside in the fall. They may not blossom extensively the next spring, but they will regain their strength and eventually produce fine outdoor spring flowers.

One final note about hyacinth: We sell “pre-cooled” hyacinth and that enables you to skip that 15 week cooling process. Put your hyacinth in pots or even easier pick up a few hyacinth vases and just place your hyacinth in water and let nature go!