any container can be used for forcing bulbs. Some do particularly well
forced only in water, and specially designed vases for forcing individual
hyacinth bulbs are available. Paperwhite
narcissus can be easily forced in a shallow container of water using pebbles
for support. Hyacinths can be forced in special hyacinth vases. More
extensive forcing projects are best done in clay or plastic pots that have
adequate drainage holes. Plastic retains soil moisture longer, and can
always be set inside a decorative outer planter.
The best soil mix for forcing bulbs contains equal parts of
soil, sphagnum moss, and perlite or vermiculite. Commercial
"soil-less" potting mixes can also be used. Bulbs for forcing
should not be planted in ordinary garden soil or in potting mixes that are
labeled "potting soil." Potting soil mixes are often no more than
a fine form of peat moss and holds too much moisture which can cause
water-related disease problems.
Fill three-quarters of the container with potting mix. Plant
bulbs closely together. Spacing considerations that apply to planting bulbs
in the garden do not apply when the bulbs are to be forced. Place tulip
bulbs with the "flat" side facing the edge of the container. After
you arrange the bulbs, place additional media around them. Do not fill the
container to the surface with the potting mix. The tops of tulip and
narcissus bulbs do not need to be covered. The bulbs should then be watered
in. Bulbs needing pre-chilling should be planted in inexpensive
plastic pots that can be set inside decorative planters.
All of the spring-blooming bulbs, with the exception of
paperwhite narcissus, amaryllis and iris reticulata, must have a cold period
of at least three months to initiate bloom. You do this pre-chilling a
variety of ways. Potted bulbs can be stored in a refrigerator or in an
unheated garage or cellar. Pots in a refrigerator tend to dry out rapidly,
so check periodically to ensure that the soil is moist.
Bulbs can be chilled in a cold frame as well. If you use
this method, make sure you open the cold frame on sunny winter days. Even
when the outside temperature is under 40 degrees F, the inside of the cold
frame can rapidly heat up, which can initiate early flowering.
A simple method involves chilling the pots under natural
cold conditions outdoors. Dig a trench or pit in the vegetable or flower
garden approximately as deep as the containers. Place the planted pots in
the trench or pit and mulch thickly with loose, dried leaves, straw or
sphagnum moss mounded up a few inches higher than the ground surface. Cover
the mound with plastic (anchor it with soil, bricks or rocks to keep in
place). The mulch acts as a buffer zone. Bulbs will receive the cold
temperatures they need but will not freeze. The plastic cover makes it much
easier to remove the pots after the cold period has been completed. The
length of the cold period needed depends on the specific bulb and, in some
cases, the cultivar. The following table gives cold treatment guidelines for
bulbs that are easily forced.
After bulbs have been chilled, bring the pots inside for
blooming. Check the pots to see if the bulbs have produced an adequate root
system (look to see if any roots are visible through the drainage holes).
The number of weeks it takes before the plants actually bloom depends on the
environmental factors in the home, but the average is two to three weeks.
the pots thoroughly when bringing them inside. Place pots in a cool area of
the home (high light intensity is not important at this point) and leave
pots in a cool location until active growth is visible. Take care not to
When the shoots are 4-6 inches tall, you can move the pots
to a warmer location that receives more light. Forcing bulbs slowly is more
desirable than placing them directly in a bright, warm location. The quick
transition from chilling to warm temperatures can sometimes
"blast" the buds, which means everything moves too fast and the
bulbs do not bloom. Because of the warmer indoor temperatures, flowers from
bulbs that are forced indoors do not last as long as outdoor flowers.
Forcing several containers of bulbs on a staggered schedule extends the
If blossoms begin to develop too quickly, you may be able to
retard blooming a bit by moving the pots out of direct sunlight and into a
cooler location. Re-acclimate them to sunlight and warmer temperatures when
you want them to resume growing.
After blooming, hardy bulbs such as hyacinths and tulips
cannot be forced again and should be discarded. Or they can be planted
outdoors where they may rebloom within a year or two.
Forcing is hard on most bulbs. The easiest after-bloom care
is pitching the bulbs on the compost pile. If you wish to recycle these
bulbs for the garden, after-bloom care is critical. The key to success is
keeping the foliage actively growing as long as possible. Bulbs will need to
be fertilized with a water-soluble fertilizer. Follow label directions.
After the foliage has died back naturally, the bulbs can be planted directly
in the garden or stored for later planting. If they do not perform well in
the garden, do not be disappointed. Forced bulbs are most useful for indoor
enjoyment. By all means, do not try to force the same bulbs the next season.
It is difficult to recreate the natural bulb cycle indoors. Most homes
simply do not have the necessary light conditions to be successful.
Unlike most other bulbs, amaryllis bulbs will bloom again
and again. See Holiday Houseplant
Care for information on amaryllis after-bloom care.
(narcissus tazetta), 'Soleil d'Or', 'Chinese sacred lily' and
colchicum are among the most popular forcing flowers that don't require the
12-week rooting period. They are easy to start and can give you indoor
blooms from Thanksgiving until late March. If you plant them
successively, batch after batch in late fall to early winter, they will
provide many containers of blooms.
Paperwhites are most often (and most easily) potted in
shallow containers of gravel. Place bulbs on a layer of gravel and carefully
fill in enough gravel to hold bulbs but not cover them. A crowded grouping
will be the most attractive.
Add water to the container. It should go just to the base of
the bulbs, but not touching the bulbs. Place container in a sunny spot, step
back and watch 'em grow! You'll see roots in a day or so and in three to
five weeks you'll have gorgeous flowers. Keep the water level at the
Easiest Bulbs for Forcing
popular bulb; grows in
soil or gravel
popular Christmas plant
(plant bulb in early November - no cooling necessary)
requires 12-14 week
rooting period; bulbs can be potted in gravel and water for different
favorite; requires about 12 weeks for rooting; can be forced in
special "hyacinth" vases using only water
excellent for forcing -
can even grow on a window sill without soil or water; begins blooming
in about two weeks
requires 16 week rooting
time; pot plenty they're small
reticulata are easy to force, but need careful attention to drainage;
require about 15 weeks for rooting; don't hold iris bulbs too long
before potting; tall-stemmed iris are less suited to forcing
Forced tulips do not do quite as well as garden
planted tulips because they require a fairly long rooting period at even
(non-fluctuating) temperatures to be successful. Allow at least 15 weeks.
Experiment with a few pots of different varieties. One to
try is the distinctive 'Princess Irene'. This single early tulip is orange
with purple flame markings. The bright yellow 'Monte Carlo' and pink
Angelique are double early tulips, a cultivar that has twice as many petals
as most tulips.
Tulip Tip: Plant bulbs with flat side facing the rim, this
will position the larger outer leaves toward the pot rim, where they will
drape gracefully over the edge of the pot.
Daffodils require very bright light, such as that
found in a greenhouse, to flower well. Too little sun results in leggy
growth and no blossoms. Only the miniature varieties (hybrid) daffodils are
recommended for home forcing. Daffodils usually require a 12-14 week rooting
Once removed from the rooting area, daffodils must be placed
in a location that receives lots of sun, say an enclosed porch or sun room
or under a skylight.
Lily-of-the-Valley are often pre-cooled when you buy
them, so they will bloom three to four weeks after planting. Ask your
Freesias don't require a cooling period, however they
usually require a lot of sunshine and about three months of growth time
before they bloom. These fragrant flowers do best in a very bright room with
daytime temperatures of about 70°F and nighttime temperatures of about