How to Grow Tulips to Bloom in December

Potted tulips require months of cold treatment to bloom.

Poinsettia and amaryllis dominate the potted florist plants available for the December holidays, but you also can have beautiful tulips at this time of year with some planning and diligence. For tulips to bloom in December, production greenhouses treat them with cold and grow them in conditions that mimic early springtime. It's a labor intensive and not always precisely timed procedure, but you can accomplish it at home.

Things You'll Need

• Tulip bulbs
• 6-inch container with drainage holes
• Potting mix
• Refrigerator

Instructions

1. Acquire fresh, healthy, dormant tulip bulbs from a mail-order bulb supplier. The tulips must arrive in July or very early August. Tell the supplier you are using these tulip bulbs to force December blooming. Early season tulip varieties are best, as they sprout and bloom more quickly compared with late-season types.

2. Plant tulips about Aug. 1 to have flowering plants by early December, but as late as Sept. 1 if flowering is desired in late December. Fill a 6-inch container half-full with moist potting mix. Gently tamp the soil down with your fingers to remove any air pockets.

3. Place five to six tulip bulbs atop the half-filled container, spacing them 1 inch apart and 1 inch away from the container's walls. Orient each bulb with the pointed tip upright and the wide bottom downward onto the soil.

4. Place more moist potting mix atop the bulbs so their tips are barely covered, no more than 1 inch below the soil surface. Gently tamp down the soil with your finger tips. Maintain a 1/2-inch gap between the soil and the rim of the container. The gap helps capture water, allowing it to soak into the soil and preventing water run off or soil erosion.

5. Place the container into a refrigerator for 12 to 16 weeks. The refrigerator must be maintained between 38 and 45 degrees Fahrenheit. Monitor the container every week, touching the soil surface with your fingertip. When it feels slightly dry to the touch, place the container in the sink and add 1 to 2 inches of cool water. Allow the water to soak in and any excess water to fully drain from the container's bottom holes. Return the container to the refrigerator 15 minutes later.

6. Move the tulip container out of the refrigerator on Dec. 1, or after a minimum of 12 weeks of cold treatment. Do not let the tulips chill in the refrigerator for longer than 16 weeks. Place the container on a sunny or bright, indirect windowsill where the temperature is 55 to 60 F during the day and 50 F at night.

7. Water the container as needed to maintain an evenly moist soil. Do not overwater to create soggy soil as that can lead to fungal disease or bulb rot. Move the container to the sink to water and allow excess water to fully drain before moving the pot back to its growing location.

8. Rotate the container 90 degrees every day once tulips sprout up from the soil. This prevents the plants from leaned toward the light as they heighten and eventually reveal their flower buds. The tulips should bloom two to three weeks after being removed from the refrigerator.

Tips & Warnings

• Ask the tulip supplier if they have any pre-chilled tulip bulbs. These already will have received treatment in a cooler at the bulb farm, reducing the time you need to keep them in your refrigerator. Pre-chilled bulbs likely will be shipped to you in October or November. As long as the bulbs received at least 12 weeks of chilling, you can plant them accordingly in containers so they bloom two to three weeks later.

• Resist the urge to place tulips in a very warm room to hasten their growth. Rooms warmer than 70 F and placement in a hot, sunny window may increase plant growth, but it also leads to weak, leggy stems or flowers that open quickly but do not last more than one or two days.

• Some early-season tulip varieties require only 10 weeks of chilling, such as Christmas Dream, Merry Christmas, Joffre and Brilliant Star. This changes the time frame for December-blooming tulips; start planting and chilling starting no later than Oct. 1.

• Do not freeze tulip bulbs. Temperatures in a deep freezer approach 0 F; this will desiccate the tulip bulb and kill the flower bud developing inside the bulb. Place the tulips only in a refrigerator that is no colder than 34 F.

References

• "Bulbs for Indoors"; Robert M. Hays, et al., eds.; 1996
• Tulip World: Forcing Flower Bulbs