Chilling Bulbs

Novice gardeners may not be aware that flower bulbs need to experience chilling so that they can grow properly. Chilling refers to the requirement that the plant need a dormancy period before it is ready for growth.

The chilling period is necessary to keep the embryo from developing during cold weather. Such an occurrence would possibly kill the new plant.

The length of the chilling period depends on the species. Moreover, some bulbs, including tropical flowers, do not need a chilling period at all.

If a gardener can imitate the chilling period that occurs in the bulb’s natural environment, then you can cheat and fool the bulb into sprouting early. This permits a burst of color for your garden during the late winter.

How To Chill Flowering Bulbs

To fool the bulb through its chilling period you need to know the amount of time the particular bulb needs to chill. For example, tulips and narcissus need a chilling period of 12 to six weeks. The highest the temperature can be for a chilling of these bulbs is about 40°F. This means that you can actually use your refrigerator to fool the bulb that it is experiencing its chilling period. However, be sure not to store bulbs next to fruit. The fruit is releasing ethylene gas, which reduces the bulb’s bloom. Put the bulb into a ventilated mesh bag before placing it into the refrigerator.

A general rule is that the flowers that bloom first, even through snow, need the least time to chill. The bulbs that bloom later need the most chilling time.

Bulbs That Need Chilling And Those That Don’t

A bulb that would normally be in the ground during cold weather needs chilling. Although a list of all that bulbs that fall into that category is just too long for show here, some of the most popular bulbs that need chilling include:

• Tulips

• Hyacinth

• Crocus

• Muscari

• Daffodil

• Snowdrop

Tulips are bulbs that require chilling.

(Courtesy: Teatsche Dijkuis at

As explained, bulbs that bloom late during the season don’t need chilling. The most popular bulbs that are in this category include:

• Amaryllis

• Paperwhite

• Ranunculus

• Anemones

Paperwhite bulbs don’t need chilling.

(Courtesy: Glenn Seplak at

Consult with your local nursery to determine if a bulb that has not been mentioned in these lists need or need not be chilled.

If you live in a warm hardiness zone, then you should not expect pre-chilled bulbs to produce many flowers. It is best to treat them as annuals.

Potting Bulbs To Force Chilling

Expect the container you use to force chill bulbs to be crowded. A 6-inch pot contains about six tulip bulbs. Be certain that the bulbs are not touching one another.

It is essential that you use a bot with excellent drainage and that you also use quality potting soil. Set the bulbs in the pot with the soil just covering the tops of the bulbs. Keep the soil moderately moist in a cool location until you see green sprouts forcing through the soil.

After flower buds begin to appear, move the pot to a window with bright sunlight. It won’t be long before you will see flowers and then they are ready for transplanting into the outdoor garden.


About Robert Janis

Written by Robert Janis for LawnEq - Your specialists for Lawn Mower Parts and Small Engine Parts. We offer genuine premium OEM parts for Land Pride, Toro and many more dependable manufacturers.