By Barb Delisio
OSU Ext. Master Gardener Volunteer
Christmas cactus is a relatively easy houseplant to grow once you realize that they are not the sun-loving, drought-loving cacti of the desert.
Christmas cacti are called “short day plants,” which means they need six weeks of 14 hours of darkness to set blooms.
To get your cactus to bloom when you want is where the difficulty lies. Count back six weeks from the time you want your cactus to bloom. For your cactus to bloom around the Christmas season, make sure the plant is in a room that gets no more than 10 hours of light — natural or otherwise — after the first week of November.
I have a window in my laundry room that gets sun during the day, but by the first of November it is dark by 5:30 or so. Something as slight as a streetlight outside your window, or car headlights can deter the plant from setting blossoms.
If you don’t have a place that is dark, setting the plant in a place where it is exposed to cool temperatures of 50-55 degrees for a time period will also set blossoms. This cool temperature eliminates the need for the six weeks of darkness.
Check every few days to make sure the soil hasn’t dried out. It is just as bad to under-water as to over- water, but never allow the plant to sit in water.
Fertilize your Christmas cactus only between April and October. It doesn’t need to be fertilized when it is setting blossoms or when the cactus is in full bloom. Also, the cactus needs to be repotted to a larger (no more than 2-inch increase) pot every three or four years. The root-bound plant produces more blooms.
A common problem with Christmas cactus is dropping unopened flower buds. This can occur from low humidity, a sudden change in temperature or light, or soil that is too dry. Stem leaves will fall off from excessive watering.
By following these simple instructions you could have a beautiful, flowering Christmas cactus to enjoy by the third week in December. Happy growing.
For more information, visit go.osu.edu/christmascactus.