Which type of holiday cactus do you have?
There are many different types of cacti that bloom between Thanksgiving and Easter. Each is appropriately named by the holiday it blooms near. The differences between these plants are found in the leaf edges. Christmas cacti have scalloped edges while Thanksgiving and Easter cacti have pointed edges. The Thanksgiving cactus is most common, probably because it is easier to get to bloom. They each are available in a variety of flower colors including white, pink, red, and orange.
When purchasing a new plant, look for uniform green growth, and good flower bud set. While "cacti" usually suggest high temperatures and dry air, this is not what these holiday bloomers prefer. Unlike most cacti, these like moist soil and cooler temperatures.
Take care of your flowering cacti much like you would any other houseplant. Give it a cool, sunny window or other location with bright, indirect light. Too much light can cause flower color to fade. Day temperatures of 70o F and evening temperatures of 60-65oF are considered ideal. Avoid overwatering during flowering. Do not fertilize when plants are flowering.
The secret of getting your holiday cactus to bloom is one of air temperature. All of these cacti require a cool night temperature of about 60oF to bloom. Long nights are important too for blooming. My parents used to always put theirs in the cool, dark basement to induce flowering. Remember, you must provide the plant a cool location with long nights. Bring it back to a cool, sunny window as soon as buds start to show. Often the Thanksgiving cactus will bloom without manipulating its growing environment, but the Christmas cactus is more fussy.
If buds start to drop, it may be an indication of one of three things: the plant may need repotting, the temperature may be too high, or the light intensity too low. These plants seldom flower well at temperatures above 70oF.
If you don't have a holiday cactus, consider getting one this holiday season. They also make great gifts that, with proper care, will provide beauty for years to come.