Q. I purchased some tulip bulbs last fall that I didn’t have a chance to plant. I potted them up and stored them in the basement. Now I have leaves, but no sign of flowers. What can I do to get them to bloom?
Foilage sprouting from tulip bulbs
Photo credit: Rosie Lerner, Purdue Extension
A. Most spring-flowering bulbs including tulips require a period of 8-16 weeks of chilling to initiate flower buds inside the bulb. If they don’t receive that chilling period, the bulbs may sprout as you’ve experienced, but will only grow foliage. There’s not much you can do to get them to bloom now that they’ve already come up.
Should you find yourself with unplanted bulbs next year, pot them up about 3-4 months ahead of when you would like them to bloom. Moisten the soil and store between 35 and 45 F. Your basement may not be cold enough, but you also do not want them to freeze. After the required chilling period, the bulbs will begin to sprout and can then be moved to room temperature and greater light exposure. The bulbs should bloom within 2-3 weeks of sprouting.
You’ll find more information in Extension publication HO-19, Forcing Bulbs for Indoor Bloom, at
https://mdc.itap.purdue.edu/item.asp?item_number=HO-19-W .