University of Vermont
Department of Plant and Soil Science
BULBS NOW FOR WINTER BLOOM
Dr. Leonard Perry, Horticulture
University of Vermont
If you ordered bulbs for this fall, and didn't plant them all, consider
potting a few for winter bloom indoors. This process is called
“forcing.” Actually, you are merely providing the right conditions for
the bulbs to bloom indoors.
Even if you planted all your spring bulbs, consider buying some more to
force into bloom indoors. Some bulb varieties are more adapted to this
than others, and are so marked. They may include such tulips as the
red and yellow Monsiella (one of my favorites), the double late pink
Angelique, the peach Apricot Beauty, the purple and white Zurel, or the
Daffodils for forcing include the small yellow and orange Jetfire, or small
yellow Tete-a-Tete, the popular yellow trumpet Dutch Master, or a more
unusual one such as the white and orange Geranium. Most fragrant
hyacinth varieties also can be forced. Some of the smaller, “minor”
bulbs you can force include crocus, scillas (squill), and grape hyacinths.
Pot bulbs in a good potting soil. Healthy garden loam may be used if
peat moss is added. A good mixture might include three parts (by
volume) of a good garden loam, two parts of peat moss, and one part of
sand. While garden soil isn’t good to use in mixtures for starting
seeds or for houseplants, it works fine for forcing bulbs.
The soil to avoid is a heavy, water-logged clay which can cause bulbs to
rot. Also make sure containers have drainage holes so water doesn’t
accumulate in the bottoms, rotting the bulbs.
For tulips, place four or five in a six-inch pot. A trick with them is to
place the flatter side of the bulb against the pot side. This is the
side of the bulb that produces the largest leaf, so it can hang over the pot
For daffodils and hyacinths, place one in a four-inch pot or three in a
six-inch pot if their size permits. You may place more in the larger
and more shallow bulb "pans." Place bulbs so their tips (“necks”) are
just above the soil surface at pot rim level. Make sure there is at
least two inches of soil below the bulb for root growth. Label your
bulbs so you remember what they are.
Water well after planting, and place pots in a dark area between 35 and 45
degrees F for at least three months. These conditions allow bulbs to
form roots and prepare to produce flower stalks. An old refrigerator
is ideal, or you can place the pots outdoors under a thick layer of straw,
in a cold frame, in a cool basement, or in an unheated garage. Just
make sure they don’t freeze, and don’t store with fruits. Many of
these emit a gas (ethylene) which can harm bulbs.
Keep the soil slightly moist. After three to four months, remove and
place in a warm, lighted area, and watch the flower buds grow and
develop. To spread the bloom throughout the winter, don't bring all
your bulbs into warmth at once. Instead, bring out at week or two-week
intervals for a continuous succession of winter bloom. You can plant
daffodils and perennial tulips outside next summer, but they may need a year
or two to recover before reblooming.
Paperwhite narcissus are tropical in origin, so they don’t require cold in
order to bloom. These are often potted in dishes of gravel, with water
kept in the base. Or, you may pot as other related daffodils.
Keep paperwhites in cool (about 50 degrees F) until roots form, then bring
into the warmth. It often takes about six weeks between potting and
bloom for this popular winter holiday flower.
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