Most spring-flowering bulbs require a rooting period (of about 10 to 20 weeks) at temperatures between 35 - 48°F (2 - 9°C) if they are to be "forced" into flower. This chilling period is essential to developing a good root system. If the roots are under-developed, the flowers will be small and floppy.

Indoor Forcing

After potting the bulbs, place pots in the an unused, but operational, refrigerator where they can remain chilled for the desired length of time (If you haven't already done so, see the table of forcing times: Bulbs recommended for Forcing). Note: this should NOT be the same refrigerator in which you keep food!

Bulbs can be chilled longer than the time suggested, but not for less time. Other indoor storage possibilities include: unheated cellars or attics, porches, or cool, ventilated crawl spaces.

Outdoor Garden Forcing

The potted bulbs can also be placed outdoors in the garden for the chilling period, provided you live in an area where the outside temperature is currently between 35 - 48°F (2 - 9°C). They can be stored in either a cold frame or a trench, but it's essential to keep the pots from freezing.

A frame should be shaded and well drained. After pots are placed in the frame, cover them with insulating materials, such as straw, if temperatures are likely to drop below 32°F (0°C).

If you choose a trench, select a sloping location (for better drainage). Mark off and dig a trench about six inches wider than the pots. Spread an inch of gravel or cinders on the bottom for drainage and set the pots in it. (Place the pots in the reverse order in which you will remove them.) Cover pots with a soft, non-compacting material such as vermiculite. Add a layer of mulch (such as hay, shredded bark or peat moss) after the first frost.

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Indoor Forcing: Introduction

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Page created and maintained by A. Steinbergs

Last modified: May 4, 2006