Forcing Indoors
Many fall planted, spring flowering bulbs may be grown indoors to bloom during winter. Some of the most commonly forced indoor bulbs are small early tulip varieties, crocuses, daffodils, narcissus, and hyacinths. Pot these bulbs in a well-drained planting mix and containers with drainage holes. Plant the bulbs so that they are only half covered with potting soil. Allow for 1 in. (2.5 cm) or more of soil below the bulbs. For best results plant bulbs with the same flowering time in the same container.
Most hardy outdoor bulbs require a cool dormancy period at 3-10 C (35-50 F) after they are potted. A cold room or an extra refrigerator can be put into use for this purpose. However, apples or cabbages must not be in the same area since they release ethylene gas which will damage the flower buds. These bulbs require total darkness during dormancy; be sure to cover the bulb pots if they are located in an unheated porch or daylight-exposed area.
The length the cool period varies depending on the type and variety of bulb. The cooling requirements for some of the popular bulbs have been listed below to help you with choosing compatible bulbs.
During the cool period keep the soil barely moist; check every week or so to make sure the soil does not dry out. If the bulbs are kept too wet they can rot; dust bulbs with Bulb Dust before planting to prevent such problems.
Hyacinths can be forced in special hyacinth glasses which are filled with enough water to touch the base of the bulb. They will still need to be cooled in water-filled glasses for 10-12 weeks.
Amaryllis
Hippeastrum species
These bulbs, usually associated with Christmas, can be easily forced to flower indoors. They produce four to six large flowers, 8-9 in. (20-22 cm) on thick, hollow stems in colors of red, salmon, pink, coral, and white with pink stripes.
Amaryllis should be planted in August to October for flowering during the Christmas season. Before planting, soak the base of the bulb in a shallow dish of lukewarm water for 12 hours. Pot the bulb in rich sandy soil to which bone meal (or a complete commercial fertilizer (5 ml or 1 tsp) to a 6 in. (15 cm) pot) has been added. Select a pot that allows for 1 in. (2.5 cm) of space between the bulb and the edge of the pot. Set the bulb so that the neck and one half of the bulb are above the soil surface. Firmly pack the soil around the base of the bulb. Keep the soil only slightly moist until the bulb starts to grow, thereafter keep the soil evenly moist.
Keep potted amaryllis in a cool place until their roots are well developed. If you want an early bloom increase the temperature to 22-25 C (70-75 F) when the leaves appear. After flower buds form feed these bulbs lightly with a complete fertilizer every two weeks throughout the blooming season. After the flowers fade cut them off. Remove the stems after they die, leaving at least 2 inches of stem on the bulbs. These plants will now produce large strap-like leaves. During the summer they need a sunny location; they may be put outdoors. Sink the pots into the ground up to the rim and fertilize and water them like you would any sun-loving annual or perennial. Bring them indoors before the first hard frost. Gradually reduce the watering and place the bulbs in a cool dark room. When the leaves have withered cut them off. Allow the bulbs to rest for several months in a frost-free dark place until the first signs of growth appear then repot the bulbs and repeat the whole process.
Paperwhites
Narcissus tazetta
These bulbs produce fragrant white daffodil-like flowers with very little effort at all. They cannot be grown outdoors but are popular indoor-flowering bulbs. They do not require a cold dormancy period to encourage blooming. Plant these bulbs in pebbles in a shallow pan filled with water to just below the top of the pebbles and they will bloom in a few weeks. Since they cannot be forced twice they must be discarded after blooming. Some varieties are:
CHINESE SACRED LILY: white and dark yellow
GRAND SOLEIL D’OR: yellow
ZIVA: white
