AMES, Iowa – Summer is winding down and fall is almost here. That means it’s time to start focusing on plants that rebloom during colder months, like the amaryllis or the Christmas cactus. They often require specialized care to reach their full potential. What needs to be done?
Iowa State University Extension and Outreach horticulturists can help answer questions about reblooming house plants. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
What is the proper care of amaryllis bulbs in the fall?
Plants that are outdoors should be brought indoors in mid-September. In order to bloom, amaryllis bulbs must be exposed to temperatures of 50 to 55 degrees Fahrenheit for a minimum of eight to 10 weeks. This can be accomplished by inducing the plants to go dormant and then storing the dormant bulbs at a temperature of 50- 55 F. To induce dormancy, place plants in a cool, semi-dark location in late September and withhold water. Cut off the foliage when the leaves turn brown. Then place the dormant bulbs in a 50-55 F location for at least eight to 10 weeks.
After the cool requirement has been met, start the growth cycle again by watering the bulbs and placing them in a well-lighted, 70-75 F location. Keep the potting soil moist, but not wet, until growth appears. The other option is to place plants in a well-lighted, 50-55 F location in fall. Maintain the amaryllises as green plants from fall to mid-winter. After the cool requirement has been met, move the plants to a warmer (70-75 F) location.
How do I care for a Christmas cactus in fall?
Day-length and temperature control the flowering of the Christmas cactus. The Christmas cactus is a short-day plant. Plants will not bloom properly if exposed to artificial light at night in fall. Flowers also may fail to develop if the plant is exposed to temperatures above 70 F. Night temperatures of 60-65 F with slightly warmer daytime temperatures are ideal for flower formation. In September, place the Christmas cactus in a cool location that receives bright light during the day, but no artificial light at night. An unused bedroom or basement may have the proper environmental conditions.
Keep the Christmas cactus on the dry side in fall. A thorough watering every seven to 10 days is usually sufficient. Continue to give the Christmas cactus good, consistent care during flower bud development. Moving the plant to another location, excessive watering, or other changes to its care during flower bud development may cause the buds to drop off. The Christmas cactus can be moved and displayed in another room when the first flower buds begin to open.
How do I care for a kalanchoe in fall?
The kalanchoe, like the Christmas cactus, is a short-day plant. Plants require short day lengths (long nights) for flower bud development. In October, place the kalanchoe in a room where the lights are not turned on at night with the plant receiving only natural light during the day. Six weeks of 14-hour nights are required for flower buds to form. Proper temperatures during this period are 65-70 F during the day and 60-65 Fahrenheit at night. Allow the potting soil to dry between waterings.