How and Why to Pre-Chill Bulbs Earlier than Planting in Fall

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After summer time’s scorching warmth, autumn’s cooler temps have arrived, signaling the time to plant spring-blooming bulbs. Fall-planted bulbs could not provide on the spot gratification however will present post-winter blooms well worth the wait. 

Relying on the place you backyard, you could have to pre-chill your bulbs earlier than planting them within the fall. As a result of most spring-blooming bulbs, together with tulips, crocus, muscari, hyacinths, and alliums, originate from climates with chilly winters, they require a number of months of chilly temperatures to bloom correctly. Gardeners in zones 8-11 with gentle winters want to present bulbs a “substitute winter” to imitate the bulb’s native setting by pre-chilling them in order that they’ll bloom accurately. With out chilling, the bulb could develop, however it could not flower. 

In Northern areas with cooler fall temperatures, gardeners can plant bulbs straight within the floor with out pre-chilling them. The bottom will develop into chilly over the winter to supply the bulbs loads of the chilliness time they’ll have to prepared themselves for a burst of spring blooms. 

In zones 8-10, bulbs reminiscent of Dutch iris, freesia, and a few daffodils, native to related hotter climates, don’t want pre-chilling. Most different bulbs, nevertheless, want publicity to 6 to eight weeks of constantly chilly temperatures (beneath 45°F) to flower properly.

Chilling fall bulbs within the fridge is a simple choice. Place them in a ventilated bag to maintain them from drying out. Keep away from storing them close to ripening fruit, which off-gasses ethylene that can harm the bulbs.

Plan to start chilling your bulbs mid to late October, ideally at 35 to 45°F for 10 to fifteen weeks. Bulbs chilled within the fall ought to be able to plant in January or February. After the pre-chilling stage, plant them instantly. Most bulbs will start blooming 4 to 6 weeks after planting.