Last week, I wrote about using poinsettias for holiday decorations. Today I will talk about another one of our showiest houseplants for this time of year – Christmas cacti.
They make great gifts because they are so easy to grow, even for that friend or relative that doesn’t have a green thumb.
The flowers of Christmas cacti include yellow, salmon, pink, fuchsia and white or combinations of those colors.
Christmas cacti do best in a humus soil. A good pot mix is equal parts soil, sand and either peat moss or leaf mold. If you prefer to buy your own potting soil, choose a good quality that drains well. Many garden centers will carry a potting mix designed for succulent plants.
Christmas cactus is not a true cactus. It is a succulent and can store a reasonable quantity of water in the leaves. Water thoroughly when the top half of the soil in the pot feels dry. The length of time between watering will vary with the air temperature, amount of light, rate of growth and the relative humidity.
During the summer, water so that the soil is continually moist. During the fall, water only well enough to prevent wilting. This is mimicking its natural habitat in the jungle. It has two rest periods, before and after rainy times. One comes just before flowering in the fall. The other time follows flowering.
Although Christmas cacti are easy to grow, many indoor gardeners give up because they cannot get them to bloom. The problem is they are not providing them with the correct conditions.
Like chrysanthemums and poinsettias, these plants what we call short-day plants. This means that shortening of the day length triggers flower-bud development. To get your plants to set flower buds, one of the following conditions must be met:
• At 50-55 degrees at night, flower buds will form regardless of day length. Christmas cactus will do best outdoors all spring, summer and fall. Even if you keep them indoors during spring and summer, take them outside in late summer, then bring them back indoors during late October or early November. Leaving them outdoors during the fall, you will be providing the night temperatures they need for flower bud development.
• At 60-65 degrees night temperature, supply 13 uninterrupted hours of darkness such as in an unused room or closet, or put a box over it.
• Flower buds seldom form at night temperatures above 70 degrees. This is the main problem with people having them in the house where it doesn’t get cool enough at night.
• After flower buds are well developed, they will flower at normal house temperatures.
Christmas cacti grow best when pot-bound so plants rarely need repotting. If you ever do decide to re-pot, the best time is in the spring. But a plant that is unhealthy because of the root system can be re-potted any time of the year.