Prepare now to brighten the darkest
days of winter
Forcing spring bulbs for indoor color
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URBANA -- Even the dullest gray days of winter can be
brightened up with colorful spring blooming bulbs grown indoors,
said Susan Grupp, a University of Illinois Extension horticulture
educator based in DuPage County. "You can create an indoor garden
with easy-to-force bulbs such as daffodils or hyacinths," she said.
"Coaxing the bulb to grow and bloom out of season is not difficult
but requires special handling."
beginning by selecting large, high-quality bulbs with no sign of
mold or blemishes. Pay attention to varieties -- some are easier to
force than others. Check the labels for those recommended for
To plant, choose
containers with good drainage. Shallow plastic or clay pots work
"You can use a
store-bought potting mix or make your own by combining one-third
garden soil, one-third peat moss or leaf mold, and one-third coarse
sand or perlite," she said. "Add 1 inch of gravel to the bottom of
the pot and then enough potting mixture to hold the bulbs so their
tips are even with the pot rim. Set the bulbs firmly against the
soil and space them so each bulb just touches the next. Crowded pots
make beautiful arrangements. "
Continue by gently
adding soil mix around the bulbs. Small bulbs such as grape hyacinth
and crocus should be covered completely. Larger bulbs such as
daffodils and tulips should not be completely covered -- their tips
should be seen.
and label the pot(s) with the date planted, type of bulb and
expected date to begin forcing.
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"The next step is
to provide a cold treatment to encourage good rooting," Grupp said.
"Most spring flowering bulbs require about 12 weeks of chilling at
temperatures maintained between 35 and 40 degrees (tulips need 14
weeks). Pots can be set in a cold frame, an unheated garage, a root
cellar or even a pit dug in the ground. Insulate the pots with straw
and protect them from rodents, using wire screening. If you use a
refrigerator, wrap each pot with foil and check periodically to make
sure it does not dry out. During this cold treatment, the soil mix
should be kept moist but not too wet."
After the proper
cold treatment period has been met, the bulbs should have developed
a good root system. At this time, you should see small yellowish
"Now you can force
them into growth and bloom," she said. "Move the pots to a cool area
(60 degrees) with bright light. Do not place in direct sunlight.
Water pots as needed. When shoots are about 2-3 inches tall, move
them to a sunny, cool window. It usually takes two to four weeks for
forced bulbs to bloom. Bring in a few pots every week for a
Grupp noted that
forced bulbs should not be forced again (except amaryllis). If you
plant forced bulbs outdoors, it may take one or two years before
they bloom again.
[University of Illinois news