Home Gardening Center Tip Sheet: Bulbs for Forcing

By Sonia Uyterhoeven

·· Bulbs ··


The Best Bulbs for Forcing Indoors


Tulip (Tulipa) bulbs are asymmetrical--one side is slightly flattened. The largest leaf of the tulips grows from this side. Therefore, plant the flattened side of the bulb facing the outside of your container. Tulips need a 14 to 16-week chilling time for best results. Good varieties for forcing: ‘Apricot Beauty’, ‘Bing Crosby’, ‘Jingle Bells’, ‘Attila’, ‘White Dream’, ‘Princess Irene’, ‘Monsella’, and ‘Estella Rijnveld’.

Dwarf irises (Iris reticulata) and spring crocuses (Crocus vernus) need to be chilled for 10 to 14 weeks, but can be forced in as few as six weeks. Good varieties of crocus for forcing: ‘Pickwick’, ‘Remembrance’, ‘Peter Pan’, ‘Flower Record’, ‘Jeanne d’Arc’, and ‘Purpurea Grandiflora’.

Hyacinth (Hyacinthus orientalis) bulbs can be bought pre-chilled by some mail order catalogs and can be grown hydroponically (in water). If not pre-chilled, these bulbs need a chilling period of 10 to 12 weeks; otherwise the process is shortened by four weeks. For hyacinths grown in water, place the bulb on the top and have it rest above the water in an hourglass shaped hyacinth glass. Store in a cool, dark place for 4 to 8 weeks, and check to make sure that the water level does not drop. Once a good root system has developed slowly bring into the warmth and light. Hyacinth stems are hollow, so if they start to bend over when flowering, you can stake them or insert a small piece of wire in them to keep upright. Good varieties for forcing: ‘Amethyst’, ‘Blue Jacket’, ‘Jan Bos’, ‘L’Innocence’, ‘Pink Pearl’, ‘Delft Blue’ and ‘Carnegie’.

Daffodils (Narcissus) require a minimum cold treatment of 12 weeks, but do best when chilled for 16 weeks. Miniature daffodils are ideal for forcing. Most daffodils require bright light to flower well; inadequate light will result in leggy plants with few flowers. Good varieties for forcing: ‘Barrett Browning’, ‘Bridal Crown’, ‘Dutch Master’, ‘Ice Follies’, ‘Salome’, ‘Pink Charm’, ‘Tete-a-Tete’, ‘Jenny’, and ‘Cheerfulness’.

Paperwhites (Narcissus tazetta cultivars) do not require a chilling period. To grow paperwhites all you need is water, pebbles, and a bowl or pot that is at least two inches deep and can hold between 3 and 12 paperwhites. Fill container half way with pebbles. Place bulbs close to each other, but not touching. Add more gravel until 1/3 of the bulb is covered. Fill with water until it comes just up to the base of the bulbs (pull gravel away from one bulb to see water level). It is often best to keep in a cool, darker room (60–65°F for several weeks until they are well-rooted before moving it to a sunny location. Either way, the bulbs will flower in about 3-5 weeks.

Amaryllis (Hippeastrum) do not require a chilling period. Plant them with at least one third of the bulb above the surface and leave one inch between the bulb and the edge of the container. Water your amaryllis in well when planted, but then keep the soil on the drier side until you see the flower stalk emerging. Once the flower stalk appears, start watering on a more regular basis. Amaryllis need a well-lit, warm place to grow until the buds begin to open. Then it can be moved to a cooler shadier location where the blooms will last longer. After the bulb finishes blooming, cut the flower stalk close to the base. Grow the plant in a sunny location and add houseplant fertilizer regularly. Stop watering and feeding in August, and allow the plant to dry out completely. It generally will need an eight week resting period. In late September, cut back foliage and re-pot the bulb in fresh potting soil. Place in a sunny location and water sparingly until growth begins again.

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Generous support for the Home Gardening Center has been provided by Kenneth and Ellen Roman.