Forcing Bulbs during Winter
Forcing Bulbs during Winter
by Wendy Wilson
Photo By: Paperwhites. Photo from Wikimedia Commons.
In Europe having blooming amaryllis, paperwhites, daffodils, tulips, and other bulbs indoors is a winter tradition. Enjoy the charm and fragrance of this tradition in your own home by forcing spring-blooming bulbs.
Selecting healthy, large bulbs is as important to forcing bulbs inside as when you plant bulbs in the ground. Large, firm bulbs will generate bigger, stronger blooms. I prefer to order bulbs from companies that import directly from Holland, but I’ve also had success with bulbs from local distributers. Bulbs are planted with the pointed end up. With some bulbs you will not see the roots plate.
Amaryllis and paperwhites are the easiest bulbs to force. They come pre-chilled and ready to pot and grow and will bloom in three to five weeks. Daffodils, tulips, hyacinths, grape hyacinths, crocus, and other small bulbs, on the other hand, need to be potted and chilled at 35 to 50 degrees Fahrenheit for 10 to 12 weeks. A cold garage or basement or a refrigerator is ideal. If you are storing the bulbs outside a refrigerator, cover them with cardboard or a tarp to provide darkness. A shed, cold frame, or anywhere that could freeze is not good: frozen bulbs turn to mush.
When potting bulbs, use damp potting soil. Do not use garden soil. There is no need to add fertilizer; bulbs come ready to grow, with all the nutrition they need. You can grow one layer of bulbs or two for a fuller display.
If you choose to plant one layer, a shallow pot (four to five inches) is ideal. Plant large bulbs (tulips, daffodils) at about two and a half inches. Small bulbs (crocus, grape hyacinths) get planted at about one inch. When the bulbs are covered with soil, their tips should be just at the dirt surface. When planting tulips, face the flat side of the bulb toward the outside of the pot. The first (lowest) leaf produced by the flowering shoot is always produced toward the flat side of the bulb. Large or small, bulbs should be tightly packed, even touching.
To layer bulbs, select a pot with greater depth (seven to eight inches). Place large bulbs below a layer of smaller bulbs: for example, tulips below, crocus above. Place the lowest layer on four inches of potting soil, add an additional inch of soil and then the next layer of bulbs. Cover with soil.
During the cooling period, keep the pots cool, dark, and damp. Check the pots every week so they don’t dry out. After the cooling period you should see half-inch to one-inch sprouts. At this point, place the pots in a cool spot (60 to 65 degrees) until you see blooms. This should take about three weeks. The flowers will last longer if they are not in direct sun. Some flowers (paperwhites and amaryllis in particular) may grow so enthusiastically that they flop. They can be supported with stakes.
Forced bulbs are a great way to enjoy spring flowers in the depths of winter.