The Christmas Cactus is a popular holiday gift and also a subject of discussion amongst gardeners as to how to care for it and what it takes to make it bloom. It always helps to know the origin of a plant to understand what makes it tick.
This plant is a succulent, tropical type of cactus but is not as drought tolerant as you might think when you hear the word cactus. In their native setting they live on tree branches in the rain forest of the Organ Mountains of Brazil. Christmas Cacti like humidity and loss of it is sometimes the reason for flower bud loss/drop.
A common concern is that the plant does not bloom. Getting this to happen requires a little info on what makes them happy. A Christmas Cactus is a short day plant meaning that they bloom when nights are about 14 hours long and daylight periods are between 8 to 10 hours long for 6 weeks. They will also bloom if exposed to prolonged cool temperatures between 50-55 degrees F. No flowers will form at night temperatures above 68 degrees F. You might like to try placing your cactus in a shady spot outdoors for the summer until temperatures get below 50 degrees F. Too much direct sunlight can burn the leaves. The naturally occurring longer nights and cool temperatures of late summer may encourage flower development. Indoors, keep the plant away from sources of hot air.
Begin the dark treatments by mid-October to have your plant blooming by the holidays. Keeping the plant in a cool temperature of about 50 to 55 degrees F starting in early November will also encourage it to bloom.
Another concern is how much water to give the plant. It is recommended to water when the top inch or so of soil is dry to the touch. The length of time between watering will vary with the amount of humidity in the air, amount of light, rate of growth and air temperature. If your plant tends to dry out or wilt frequently it may be time to repot it. Christmas Cacti require well drained soil. You can use a commercial mixture made for succulents or make your own by combining two parts plain potting soil with one part clean sand or vermiculite.
As always, Happy Gardening!
The Purdue University Cooperative Extension Service can be reached at 499-6334 in LaGrange Co.