How and Why to Pre-Chill Bulbs Before Planting in Fall

October 20, 2022 by


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After summer’s scorching heat, autumn’s cooler temps have arrived, signaling the time to plant spring-blooming bulbs. Fall-planted bulbs may not offer instant gratification but will provide post-winter blooms worth the wait. 

Depending on where you garden, you may need to pre-chill your bulbs before planting them in the fall. Because most spring-blooming bulbs, including tulips, crocus, muscari, hyacinths, and alliums, originate from climates with cold winters, they require several months of cold temperatures to bloom properly. Gardeners in zones 8-11 with mild winters need to give bulbs a “substitute winter” to mimic the bulb’s native environment by pre-chilling them so they’ll bloom correctly. Without chilling, the bulb may grow, but it may not flower. 


In Northern regions with cooler fall temperatures, gardeners can plant bulbs directly in the ground without pre-chilling them. The ground will become cold over the winter to offer the bulbs plenty of the chill time they’ll need to ready themselves for a burst of spring blooms. 

In zones 8-10, bulbs such as Dutch iris, freesia, and some daffodils, native to similar warmer climates, don’t need pre-chilling. Most other bulbs, however, need exposure to six to eight weeks of consistently cold temperatures (below 45°F) to flower nicely.


Chilling fall bulbs in the refrigerator is an easy option. Place them in a ventilated bag to keep them from drying out. Avoid storing them near ripening fruit, which off-gasses ethylene that will damage the bulbs.

Plan to begin chilling your bulbs mid to late October, ideally at 35 to 45°F for 10 to 15 weeks. Bulbs chilled in the fall should be ready to plant in January or February. After the pre-chilling stage, plant them immediately. Most bulbs will begin blooming four to six weeks after planting.

1 Comment

  1. How and Why to Pre-Chill Bulbs Earlier than Planting in Fall - Garden Sweet Spot Pingback said:

    […] Class: Creating Tags: fall-planted bulbs, pre-chilling bulbs, pre-cooling bulbs, spring-blooming bulbs Loved this put up? Subscribe to City Gardens! share | e-mail a buddy | feedback (0) […]

    — November 25, 2022 @ 15:32

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