Coaxing Flower Bulbs

Child preparing Amaryllis bulb in a garden container"A bulb is a promise," Wendy Sherman tells her preschoolers in Sudbury, MA. "You can do your part to provide certain conditions for them, and then you have to hope that nature comes through with the rest." These marvelous packages, each containing a complete miniature plant and its lunch, can brighten winter classrooms with the prospect of spring and provide a captivating theme for studies across the curriculum.

Light Up Young Minds
Take the history of bulbs. Students can discover why it's paved with intrigue and greed, hysteria and financial ruin. Tulips were once considered more valuable than gold! All kinds of flower bulbs have had fascinating journeys from their places of origin to other parts of the world. These tiny packages are clever adaptations that enable plants to survive harsh growing conditions. Those that thrive in classroom conditions grow so quickly that they inspire math minds and science investigations. Additionally, decorated containers of bursting buds make great gifts.

Underground Personalities
Flower bulbs generally fall into two groups. Spring-flowering bulbs are generally planted outdoors in the fall except in the warmest regions. Not only can they survive cold winter months, but these hardy bulbs actually need a period of chilling in order to bloom in the spring. This category includes daffodil, tulip, crocus, and hyacinth bulbs. Summer-flowering bulbs, many of which originated in tropical climates, are much more tender. In colder climates, you need to plant them outdoors in the spring after the last frost and dig and store them indoors in the fall and winter. Amaryllis, dahlia, and gladiolus bulbs are in this category.

But in the cocoon of your classroom, your students can coax both groups of bulbs to reveal their resplendent flowers by providing the right conditions for growth. So what if a little trickery is involved! In this Classroom Project, we share advice on bringing on the blooms. The Curriculum Connections feature ideas for using burgeoning buds as springboards for learning.

Materials

(Note: You can purchase bulbs at local garden centers and nurseries or through print or online catalogs. Paperwhites for growing indoors are available each autumn from the Gardening with Kids Shop along with collections of spring-flowering bulbs.)

• For paperwhites: container without drainage holes; clean pebbles (1/4 to 1/2 inch in diameter); large, firm paperwhite narcissus bulbs; water

 

• For amaryllis: container with drainage holes that's about 3/4 inch larger in diameter than the bulb, well-drained potting mix

 

• For spring-flowering bulbs: firm bulbs (see list, below), pot or other container with drainage holes (or a special vase for hyacinths), well-drained potting mix

Coaxing Flower Bulbs

Forcing Paperwhite Narcissus

Paperwhites are easy to bring to flower indoors, since they don't need a special chilling or rest period. Their delicate flowers have a strong fragrance that some people relish and others abhor!

1. Prepare the container. Fill a container without drainage holes with pebbles to within an inch of the rim. You can use a plastic or clay pot, or encourage students to think creatively about alternative materials. For instance, students might find and decorate a variety of recycled containers, or substitute colored stones, marbles, or other medium.

2. Plant the bulbs. Set the bulbs on the surface of the pebbles, crowding them together so they almost touch. Add more pebbles, covering the bottom third of the bulbs. Make sure the bulbs are not actually touching the water, or they may grow mold.

3. Water and wait. Maintain the water level described above and leave the bulbs in a cool location (60 to 65 degrees F) with little or no light. (This cool darkness encourages growth.)

4. Check for growth. After a week or two, have students tug gently on the bulbs from time to time to test for root develpoment. Once the plants feel rooted, move them to a bright spot without direct sunight. They should flower in three to five weeks.

Tips: Paperwhites last longer when temperatures are no warmer than 65 degrees F. If it's too warm, they'll grow quickly and become floppy. To keep them standing tall, you can support them with a circle of sticks and twine.

Nurturing Amaryllis: Tropical Treasures

These tropical natives are dramatic, fast-growing bulbs with brilliant blooms bound to captivate your class of indoor gardeners year after year. And they make wonderful holiday gifts if you plant them in early November. Unlike bulbs from cool climates that require chilling, the amaryllis hails from warm regions and will bloom 4 to 6 weeks after planting. Here's how to do it:

1. Plant the bulb. Plant amaryllis in moist potting mix with about 1/3 to 1/2 the bulb protruding above the soil. Since amaryllis thrive in cramped quarters, leave no more than 1/2- to 1-inch of space between the bulb and the container.

2. Water and wait. Leave the pot in a warm, well-lit spot, and don't water it again until the first leaf or flower bud starts to grow. Then keep the soil moist. Since timing varies, this should provide some suspense for your sharp-eyed classroom observers.

3. Enjoy the blooms. Flowers will usually appear in five or six weeks. When they appear, move the plant to a cooler spot out of direct sun to lengthen the life of the flowers.

4. Prepare it for another year. To make amaryllis bloom another year, cut off the flowers once they've withered, but leave the stalk and leaves. Leave the plant in a sunny window or GrowLab® and treat it as you would any houseplant, watering and fertilizing it regularly. Leaves require light, nutrients, and water to photosynthesize and produce food for another year of growth and flowering. The leaves will turn yellow and die in late summer or fall, signaling the plant's dormancy. Remove the leaves, stop watering and fertilizing, and store the pot in a cool basement until signs of new growth appear in the winter, and the cycle begins again.

Putting on the Chill (Coaxing Spring Bulbs Indoors)

Spring bulbs are typically planted in the ground in the fall where they spend a cold winter, not resting but growing roots, which give them a head start on the spring. Because true bulbs contain a miniature plant and stored food (starch), they're ready to spring forth when conditions are right for flowering. By simulating the natural conditions bulbs experience outside, you and your students can coax bulbs to bloom during midwinter. (See the Easiest Bulbs for Indoor Forcing list, below.) You can purchase those that have been pre-chilled for forcing or, better yet, have your students create the artificial winter bulbs need. In either case, the largest, firmest bulbs will produce the best show.

1. Pot 'em up. Use clean pots or containers with drainage holes and fill them with soilless potting mix or potting soil. Place 2 inches of soil in the pot and place bulbs on it so they're almost touching. Add enough soil to fill the pot and water well so the soil settles.

2. Simulate winter. Challenge your students, as a class or in small groups, to brainstorm how to provide a "winter" for your potted bulbs. If you have enough bulbs to spare, have students test several of their ideas, even those you think may not succeed. Ideally, the potted bulbs should be kept at temperatures between 35 and 50 degrees F (40 to 45 is ideal), and placed in paper bags or under boxes or burlap to exclude light. Consider leaving them in a cool cellar, unheated garage, or refrigerator, or buried in a cold frame under soil or leaves. Make sure they don't freeze.

Check the soil every four weeks, and water if it's dry to the touch. Leave the bulbs under these cold conditions for 10 to 15 weeks, by which point a root system and small pale shoots will have emerged.

3. Bring on spring. To encourage strong shoots and to acclimate them to their new conditions once you bring them out, keep bulbs out of direct sun or bright light for several weeks. Water when the soil is dry to the touch. The white shoots will soon turn green as they begin to develop chlorophyll and photosynthesize. As soon as flower buds appear, put pots in brighter light on a windowsill or GrowLab®. Once the flowers bloom, in about 2 to 4 weeks, less direct light and cooler temperatures will encourage them to bloom longer.

Tip: Although most bulbs cannot be forced to bloom indoors more that once, many stand a chance of blooming the following year if planted at the recommended depth outdoors once the weather has warmed in the spring. (Note: tulips that have been forced will typically not bloom again.)

Easiest Bulbs for Indoor Forcing

Tender Bulbs (No chilling required)

Paperwhite narcissus — Grow in gravel or sand.
Amaryllis — Plant in early November for holiday flowers.

Spring-Flowering Bulbs (Need chilling)

Crocus — Chill for 12-14 weeks. Grow in gravel or water.
Hyacinth — Chill for 12 weeks. Grow in special 'hyacinth' vases of water.
Dwarf iris (Iris reticulata) — Chill for 15 weeks. Grow in well-drained soil mix.
Grape hyacinth (Muscari) — Chill for 16 weeks. Grow in soil mix.
Tulips — Chill for at least 15 weeks. Grow in soil mix.
Daffodils — Chill for 12-14 weeks. Provide lots of strong, bright light for forcing.