Regional Gardening Reports :: National Gardening Association

In the Garden:
Pacific Northwest
December, 2004
Regional Report

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Classified as an early-blooming single, this 'Orange Monarch' tulip required fourteen weeks of chilling and two weeks of average household temperatures to force it into bloom.

Forcing Bulbs for Indoor Winter Color

Sometimes garden catalogs just aren't enough to get me through the winter. I need living, blooming plants to make me smile, which is why coaxing bulbs to bloom indoors is one of my favorite winter traditions. With a little preparation, most spring-flowering bulbs can be forced to bloom out of season. Paper white narcissus bulbs are the easiest to force, followed by hyacinths, daffodils, and tulips. If you've never forced bulbs before, start with paper whites and work your way through the list of the more challenging ones.

Paper Whites
I've found that the standard paper white narcissus, along with the yellow versions 'Grand Soleil d'Or' and 'Chinese Sacred Lily', grow well in water and pea gravel. The bulbs swell considerably during growth, so place them at least 1 inch apart in your container. A 4-inch pot can hold one bulb. A 6-inch pot can hold three, and a 7-inch pot, five or six. Place bulbs so their necks stick out about 1/2 inch above the gravel surface. Fill with water to just below the gravel.

For best growth, put pots in a dark location with temperatures from 40 to 55 degrees F. for two weeks, or until you have 2 to 4 inches of top growth and a vigorous bed of roots. I think a cool basement or garage is perfect for this root growth phase of forcing. Once top growth is visible, bring the pots into a bright, warm place. In about four weeks you'll have a mass of blooms with a heavenly fragrance.

Bulbs with Chilling Requirements
Many spring bulbs, such as tulips and daffodils, require a chilling period. Start by choosing bulbs marked "suitable for forcing," because varieties differ in their growth habits. Next, pot bulbs in a good potting soil. For tulips, place three bulbs in a 5-inch pot, five or six in a 6-inch pot. For daffodils and hyacinths, place one in a 4-inch pot or three in a 6-inch pot, if their size permits. You may place more bulbs in the larger, shallower bulb pans.

Water well after planting, and place in a dark area at 40 degrees F. for 12 to 15 weeks. These conditions allow bulbs to form roots and prepare to produce flower stalks. A refrigerator is ideal, if you have the room to spare. If not, place the pots outdoors under a thick layer of straw or in a cold frame.

Keep the soil slightly moist. After three to four months, remove and place in a warm, lighted area, and watch the flower buds grow and develop. To spread the bloom throughout the winter, don't pot all your bulbs at once. Instead, pot up at two-week intervals for a continuous succession of winter blooms.

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