Forcing bulbs to bloom is all about fooling Mother Nature into believing that spring has sprung. It’s not difficult or time consuming and the results can be extraordinary. All it takes is the right bulbs, a glass vase or pot, some rocks, water or potting soil and a few minutes of your time.
The process of getting bulbs to grow (forcing) occurs when you create a situation inside that replicates what Mother Nature does outside. If you decided you want to bring some garden beauty indoors, make sure you select the appropriate bulb.
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.
Don’t be afraid of making a mistake, because the worst that can happen is that the bulb won’t bloom or it rots, but the joy of seeing a plant grow and blossom is well worth it. So be brave and fool Mother Nature, she won’t mind!
- 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 Forcing
- 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.
- 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.
For more information about forcing bulbs, Google, “forcing bulbs California, or check out California Bountiful – one of the resources for this blog.