Forcing bulbs will provide indoor winter blooms

By Kathy Hatfield
Gardening Columnist

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Each year, Holland raises billions of flower bulbs to export, and gardeners in the United States are the biggest buyers. If you've purchased some spring-flowering bulbs to plant outside this fall, you might want to consider saving a few to coax into bloom inside during the winter months.

When we plant bulbs outside, they overwinter, and when the weather is cooperative, they grow roots to get a head start on spring. To force bulbs into flowering inside, you'll have to provide most of them with the winter conditions that they would endure in their natural environment.

A flower bulb is actually a miniature plant, with its own stored food, ready to emerge in the spring when conditions are right for it. If you were to cut a bulb in half from top to bottom, you would see a tiny flower bud in the center, surrounded by scales that protect it. The scales also contain food that the developing bud will use for growth.

When selecting a container for your bulbs, choose one that has a drainage hole if you are planting the bulbs in potting soil. Clay pots work well and are attractive, but they tend to dry out faster than pots made of other materials, so the bulbs may need to be watered more frequently.

Put about 2 inches of potting soil in the pot. Plant the bulbs close together; a grouping of an odd number of bulbs is generally most pleasing. Add enough soil to cover the bulbs and water them well. At this point they will need to be stored in a cool, dark place for the number of weeks indicated for each type of bulb. Keep the bulbs moist, but not soggy. Ideal temperatures are above freezing, from 35 to 45 degrees, so that the bulbs will root. If the temperatures are too high during this period, the flower will bloom inside the bulb and die.

Label the container with the type of bulb and the date, so that you will know when to remove them from their cold storage.

When the bulbs begin to sprout, they are ready to come out of cold storage. As they receive more light, the plants will turn from a pale to a darker green. Start by putting them in bright, indirect light. When the stems are 4 to 6 inches tall, move them to a bright sunny window so that they will bloom. Once the bulbs are blooming, the flowers will last longer if they are kept in a somewhat cooler location at night.

Paperwhites are one of the easiest bulbs to force because they don't need a cooling period. They are extremely fragrant, and most people either really like the scent or can't stand them. To force paperwhites, place the bulbs on a bed of pebbles or marbles in a container without a drainage hole. Put a few more pebbles around the bulbs to hold them upright. Add water to the container, but keep it below the tops of the bulbs, or they will rot. The paperwhites will develop roots within a week or two and should be moved into bright, indirect light. They should bloom in another three to four weeks.

Here are a few of the best bulbs for forcing along with the cooling period required.

Amaryllis - No cooling period is necessary for amaryllis. Plant it in early November if you want it to flower for the holidays.

Crocus - 12 to 14 weeks.

Daffodils - 12 to 14 weeks. Provide lots of strong, bright light for forcing.

Grape hyacinth (Muscari) - 16 weeks.

Hyacinth - 12 weeks. These can be forced in special hyacinth vases using only water.

Iris, dwarf (Iris reticulata) - 15 weeks.

Paperwhite narcissus - Does not require a cooling period. Grows in soil or stones.

Tulips - At least 15 weeks.