Those bags of tulips, daffodils, and crocuses appearing in garden centers every fall aren’t being sold months early by accident. Many familiar spring-flowering bulbs actually need an extended period of cold before they’ll develop and bloom properly, which is why gardeners traditionally put them into the ground before winter rather than waiting for spring.
The process is called vernalization, and understanding bulb chilling time becomes especially important if you live where winters are mild or you’re trying to force bulbs indoors. Depending on the flower, the necessary cold period can stretch from roughly 10 to 17 weeks. Give bulbs the winter conditions they expect, and those seemingly dormant packages can become some of the earliest color in next year’s garden.
