Greenhouse Bulb Forcing Tips

Greenhouse Growing Tips

Great greenhouse tips and useful information to
keep your greenhouse running efficiently.


  ::Garden Tips

Bulb Forcing
for Special Occasions

bulbs that are forced to flower in mid-winter are special attractions.
A pot of flowering bulbs for Christmas or any other special occasion is
a nice gift to give or receive.

Forcing may not be the best term to describe the process. Manipulation,
influencing, or coaxing may be better descriptions. In forcing bulbs,
you’re stimulating the natural conditions that cause bulbs to bloom. The
end results are flowers that bloom months before their usual cycle. Perhaps
you have tried to force spring bulbs in the past, only to have their weak
stems flop over, or to have the flowers drop just before opening. This
is common, and is most often caused by lack of a cool period. The majority
of spring-blooming bulbs need 10-12 weeks of cold outdoor temperatures
after they are potted to develop roots that are strong enough to support
stems and flowers.

Growth of spring bulbs and corresponding temperature can be divided into
4 stages. Duplicate these 4 natural stages and they will flower earlier
than normal.

Stage 1 is dormancy, or near
dormancy. This is when the bulbs are planted.

is root growth. Light is not necessary for this
stage, and temperatures should be in the 41° F – 45° F range.
One of the best ways to maintain this temperature range is to bury the
pots in the ground 6-8 inches deep. Other common areas used for rooting
bulbs are cool cellars, old refrigerators, garages or outdoor sheds. Always
keep the soil moist. If the temperature approaches freezing, roots cease
to grow. When the temperature goes above 54° F – 55° F, top growth
may begin prematurely.

is when top growth begins. Light should be strong,
but temperatures should be cool, in the 55° F – 65° F range.

– After 2 to 3 weeks at Stage 3, move into a warmer
temperature of 68° F – 72° F and watch the beautiful flowers pop
into bloom.

For forcing, use a good, well-drained potting soil. Don’t
worry about fertilizer; the bulb contains all its own food.

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