Califonia Bountiful

Gardening: Spring forward

Sept./Oct. 2009 California Country magazine

Prepare bulbs now for early flowers and indoor fun.

Forcing bulbs brings blooms to winter

Perhaps you can fool Mother Nature—or at least tease her into believing spring is just around the corner. And while you're at it, let the kids help. They'll have some fun and also learn how Mother Nature coaxes those beautiful flowers from knobby, misshapen, dead-looking bulbs.

It's easy as one, two, three. A few bulbs—paper whites are easiest for starting—a glass vase, some rocks, water and voila! You're in business.

It's called forcing bulbs, and it simply means duplicating conditions inside that encourage bulbs to grow and bloom weeks ahead of schedule. Already, paper white narcissus bulbs sit perched in a vase above a layer of pebbles. The slim green foliage stretches upward while the white roots snake through the rocks. A giant amaryllis bulb sits above a layer of river rocks in a tall vase. Fat buds show on the increasingly long stems. Pots of tulips sit in the refrigerator getting their requisite 12-week chilling. Tiny crocus bulbs, perched above beds of gravel in teacups, will bloom for holiday parties.

The most common bulbs for forcing are narcissus, hyacinths, tulips, crocus and amaryllis. Generally, irregularly shaped bulbs (tulips, freesias) force best in soil, while regularly shaped bulbs (paper whites, crocus) do best over water. Forcing in soil is more foolproof than water, and all bulbs can be forced in soil. You can buy special vases for forcing hyacinths and amaryllis. You can also buy complete kits. Once you know how it's done, you'll want to find unusual containers for forcing bulbs.

Forcing bulbs is easy because everything the bulb needs to grow and bloom is already stored inside. And kids love it.

Don't be afraid to experiment. It's like baking bread. How long do you knead it? How do you know if it's risen enough? It's a bit of a mystery when you're first getting started, and you're going to make mistakes, but once you've got it, you've got it.

Pat Rubin is a long-time gardener and garden writer. Send questions or comments to her at

Forcing bulbs


  • If bulb rots: Water level is too high. The water should just be touching or barely below the base of the bulb and not covering it.
  • If bulb fails to bloom, bud doesn’t develop properly or flowering spike is very short: Not enough chilling. Most bulbs, except narcissus and amaryllis, need to be kept at 40 to 50 degrees F for several weeks.
  • If foliage gets too tall: Bulbs have been kept in the dark too long or did not receive enough sun when growing. An east or south-facing window is ideal.


  • Ethanol alcohol, which is found in most hard liquors, can act as a growth regulator and keep paper white narcissus shorter and more compact during forcing. Use plain water the first seven to 10 days. Once the green shoots are 2 to 3 inches tall, replace the water with one part alcohol to seven parts water. Foliage will be more compact, but with blooms just as large and long lasting as usual.
  • Pre-chill bulbs (except amaryllis) in bags of damp sphagnum moss or damp potting soil in the refrigerator. Label bags.
  • Choose firm bulbs with no soft or rotten spots.
  • Plant tulips with the flat side of the bulb facing outward. Choose single early tulips. They are easiest since they are programmed to bloom early anyway.
  • Pot amaryllis two weeks apart for a succession of blooms. With amaryllis, the bigger the bulb the better.
  • Discard bulbs after bloom or plant them outside.
  • Change out the water weekly if it becomes murky.

Instructions for easiest bulbs to force

  • Force in water in a forcing vase. Fill water to just below the bulb. Never let a bulb sit in water.
  • Chill 12 weeks in the forcing vase until roots fill the vase and shoots are 2 to 3 inches tall. Remove from the refrigerator and place in a sunny location.
  • Weeks to bloom: Two to four.
  • Tips: Chilling period is critical for hyacinths to bloom. You don’t have to choose the largest bulbs. Flower spikes can get top-heavy, so be careful vases don’t fall over.
  • Force in soil. Cover bulbs with 1/2 inch of soil. Water.
  • Chill 10 to 15 weeks in the refrigerator.
  • Weeks to bloom: Three to five.
  • Tips: Pack bulbs tightly together with the flat side facing outward. Single early varieties work best. Tulips are the most time-consuming to force.
  • Force in a special vase in water. Don’t let water touch the bulb.
  • No chilling necessary.
  • Weeks to bloom: Four to six.
  • Tips: Start in a warm, dark place, then move to the light when the stalk is 2 to 4 inches tall. Flowering stalk can be top-heavy, so add pebbles to the vase. Choose the biggest bulbs.
  • Force over water in special vases or on a bed of coarse gravel. Plant pointed side facing up.
  • Chill 12 to 15 weeks in a paper bag or forcing vase.
  • Weeks to bloom: Two.
  • Tips: Pack corms tightly together in a low vase. (Corms are technically swollen, underground stems, but are also known as bulbs.) Hybrid crocus perform better than the smaller species types.
  • Force in water on pebbles or in soil. Fill the container with water to just below the bulb. The bottom of the bulb should just be in contact with the water. In soil, pack bulbs in tightly for a nice display of flowers.
  • Chilling period: None required.
  • Weeks to bloom: Five to seven.
  • Tips: Use a container that is twice as wide as high. Place in a cool spot until buds show color, then bring to a sunnier spot to bloom. They can get top-heavy, so be prepared to tie floppy leaves to a bamboo stake.

Gardening tips for September/October

  • Broadcast wildflower seeds like poppies and lupine for spring bloom.
  • Annual flowers are arriving in nurseries. It’s time to buy and plant snapdragons, pansies, violas, calendula, stock, sweet alyssum and more.
  • In the vegetable garden, plant cauliflower, broccoli, lettuce, beets and onions. Remember to add compost to the soil when planting.
  • Divide overgrown perennials when they finish blooming. This includes daylilies, agapanthus and many ornamental grasses.
  • Plant garlic in October for harvest next June.
  • Clean up the summer vegetable garden: Pull weeds, compost spent vegetable plants and add compost.
  • Fall bulbs begin arriving. Check out the selection and plant something you’ve never tried before. Remember to plant bulbs in clumps outdoors so they look natural. Start planting daffodil bulbs. Plant every two to three weeks for a long spring bloom season.
  • If you want to add fall color to the landscape, visit nurseries to see what looks beautiful. Don’t forget herbaceous perennials that look as beautiful in their fall dormant garb as they do at their peak. This includes ornamental grasses like miscanthus and calamagrostis, as well as sedums, black-eyed Susan, purple coneflower and more.
  • If you’ve put houseplants outside for the summer, now is the time to bring them in. Quit fertilizing them until next spring.

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