Grow Guide: Forcing Bulbs
Image courtesy of Felder Rushing
Q: Last year I bought some bulbs to grow indoors in water, and did everything they said I should do, even putting them in the refrigerator for a few weeks. But they never bloomed. What did I do wrong?
Lots of gardeners have found that, for winter color and fragrance, some types of flower bulbs can be forced to grow and flower indoors with a little special treatment. According to Art Wolk, author of Bulb Forcing for Beginners and the Seriously Smitten, there are two common reasons for bulbs "forced" to bloom indoors in pots of soil or bowls of water not blooming:
- Not being pre-chilled long enough (it can take several weeks for some bulbs).
- Storing them in the same refrigerator in which you keep fruit, which gives off a ripening gas called ethylene that can kill bulb flower buds.
Some bulbs, including many of the “paper white” group (Narcissus tazetta), amaryllis and some grape hyacinths, don’t need much pre-chilling, if any at all. Others, including hyacinths and tulips, may need to be refrigerated for six weeks or more before planting in pots.
Unless you have a separate fridge just for the bulbs—so they don't have to share shelf space with apples or oranges—there may not be much of a way around the ethylene thing. You may need to just stick with the easier kinds of bulbs for forcing.
By the way, many people are frustrated by paperwhites that get too tall and flop over indoors. Researchers at Cornell University found that if you put just a little alcohol in the water used on forced bulbs—about 1 part alcohol to 5 or 6 parts water—the bulbs will bloom on time with the same size and same fragrance, but on much shorter stems. Clear drinking alcohol or denatured alcohol both can work; an online search will turn up more specific instructions. Also, when one year I couldn’t easily find any gravel for holding bulbs upright in my bowl of water, I tried some old Mardi Gras beads, and they worked like a charm—and looked charming as well!
Gardening expert and certified wit Felder Rushing answers your questions and lays down some green-wisdom. You can get more of your Felder fix at www.slowgardening.net.