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In the heart of every bulb, a shy, still bud waits. It is anticipation itself — the promise of spring.
Winter warms, and the tiny life form stirs. It pushes shoots and roots through the soil, followed by stems, leaves and, finally, flowers. Mother Nature keeps her promise.
That is, unless an impatient gardener intervenes. In a horticultural sleight of hand called “forcing,” a bulb can be made to bloom ahead of schedule. It is a transformation triggered by temperature. “Forcing bulbs,” says expert Brent Heath, is “tricking nature to perform out of season.”
Heath comes by his expertise honestly. In 1900, his grandfather fell in love with a daffodil. Four generations later, his family sells blooming bulbs, seeds and plants to gardeners across the country from their commercial farm, Brent and Becky’s Bulbs, in Gloucester.
During the holidays, forcing bulbs to bloom indoors is a welcome diversion. As gifts or as living decorations, they are a cheery break in winter’s tedium. It’s a simple rescheduling that starts with a bit of seasonal sorcery.
“Spring-blooming bulbs are native to the Northern Hemisphere,” Heath explains. “They need to experience cold,” like winter, as part of their bloom cycle. “Daffodils, tulips, hyacinth, iris and muscari should cool at 35 degrees for 12 to 14 weeks,” he says. “You can put them in the refrigerator, but fruits and vegetables give off ethylene gas as they ripen, which will cause the blooms to abort. Best to store them in a spare fridge.” Or simply purchase pre-chilled bulbs.
Varieties that have their ancestral roots in the Mediterranean, southern Spain, Portugal and France are referred to as “tender” bulbs and can be forced without a cooling period. These include paperwhites, hippeastrum and oxalis, which can be coaxed into bloom in January, February and March with bottom heat or a room temperature of 70 degrees. Paperwhites should be retired to the compost heap when their blooms fade, since the stress of forcing depletes them of the energy they need to bloom again. But other bulbs can be planted outdoors in the spring where they will regenerate after a season or two.
The amaryllis, a popular bulb available around the holidays for decorating and gift-giving, is a different animal. It fares best by letting the soil dry completely between waterings and resting in a warm, sunny spot until the bud shows color. Then move it into bright, indirect light to bloom. When the bloom is spent, the remaining foliage does well in full sun, indoors at first then outdoors when the weather warms up, to store energy for next year’s bloom. Bring it indoors before fall’s first frost and let it rest for eight weeks in a dark spot without water. And start the fun all over again next season.
To try your hand at forcing some floral fun, follow these tips, and let the happy anticipation begin.
- The right stuff: Fill a pot with coarse potting soil. (Pebbles or shells will work, but because soil helps plants absorb nutrients, the results will be less successful.)
- Room at the top: Arrange the bulbs, root end down, with the top two-thirds of each bulb exposed. Allow 1/4 inch of head space for watering.
- Just add water: Immediately after planting, water the bulbs thoroughly. Then keep them moist but not wet. They’ll need more water as their buds and blooms emerge.
- Location, location, location: Keep potted bulbs at 50 to 60 degrees until the first green shoots appear, then move them to bright sun in a warmer space (70 degrees). Prolong the bloom by moving the plant to overnight in a cool spot. If indoor plants get leggy from stretching toward the light, Heath recommends putting them close to a grow light or forcing them on a heat mat in a cool room.
- All in good time: Expect flowers in three to four weeks.
