While the poinsettia remains the most popular of the holiday plants, a healthy Christmas cactus in full bloom is a great gift idea for that special gardener. They are easy to care for and can be grown indoors throughout the year. Flower colors include yellow, salmon, pink, fuchsia, white, and combinations of these colors. The Christmas cactus (Schlumbergera bridesii) originated from a group of epiphytic cacti native to the South American jungles.
Temperature and Light
While the Christmas cactus can adapt to low light, more abundant blooms are produced on plants that have been exposed to high light intensity. Keep your plants in a sunny location indoors. Plants can be moved outdoors in summer but keep them in a shady or semi-shady location. Too much direct sunlight can burn the leaves. When it’s time to bring the plants back inside in the fall, slowly adjust the plants to life indoors by gradually increasing the number of hours they spend indoors each day. If you want to grow it indoors in a south or west window, you should shade the plant with a shear curtain. No diffusion of light is needed on the north or east. Move the plants to shady porches or patios or plunge the pot in a shady spot in the garden during the summer months. Christmas cactus needs shading from the sun between May and September.
Christmas cactus prefers warm temperatures, although evening temperatures of 50 to 55°F can be used to initiate flower bud formation, which is responsive to day length. From October on, keep the plant where it is cool at night (60 to 65°F). Keep away from drafts, heat vents, fireplaces or other sources of hot air.
Water, Fertilization, and soil
The plant is not quite as drought tolerant as the name ‘cactus’ implies. It is a succulent plant 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 to the touch; add SUPERthrive (one drop per cup or ¼ tsp. one gallon of water) to each watering. 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. When fall arrives, water the plant only well enough to prevent wilting.
In October, give the plant no water. Cautiously resume watering in November, but don’t let stems get flabby from over watering. If the atmosphere is dry, place the pot on a tray of pebbles. Keep pebbles moist with water in the tray.
Once completely bloomed, let the plant rest by withholding water for six weeks. When new growth appears, repot and top-dress with fresh soil. Resume watering with SUPERthrive to keep soil moist, but not soggy. As tender growth appears in the spring, apply a weak solution of liquid houseplant fertilizer at two to three-week intervals.
Well-drained soil is a must for Christmas cactus. When repotting, we recommend using G&B Organics Palm, Cactus & Citrus Planting Mix according to the directions.
Shady conditions or filtered light are necessary for Christmas cactus to thrive. You can force bloom by setting the plant in a cooler location (60 to 65°F), where the light is low but not absent during the day. Do this soon for Christmas bloom. Do not let the soil dry completely, but water infrequently to keep the soil just moist. Watch for signs of buds at the ends of the leaves; increase humidity and light when they appear. If buds appear too soon, hold them back by reducing the temperature.
Propagation and re-potting
Taking short Y-shaped cuttings of the stem tips easily propagates the Christmas cactus. A well-tended cactus will reach unmanageable size in time. To take root cuttings for new plants, cut back shoots from the tips at the second joint of each tip. Place cuttings in a moist peat and perlite, or peat and sand mixture. Water sparingly at first to prevent rotting of cuttings. After two or three weeks, water as you would any other cutting. When cuttings are rooted, pot them in a very loose mixture of good potting soil.
Plants should be re-potted every two or three years or whenever the pot is filled with roots and the soil appears to be depleted of nutrients. Christmas cactus is typically re-potted in the spring, but plant with an unhealthy root system can be re-potted at any time of the year.
Bud Dropping and Development
Common causes of bud dropping are overwatering, exposure to cold drafts and heat sources, or lack of enough potash in the soil. Water the plant sparingly and feed a little liquid manure weekly.
These plants are easy to grow but are sometimes difficult to bloom. Medium light intensity and soil high in organic matter are recommended. Do not allow the plant to dry out; water when the soil surface begins to feel dry. The plant may be kept drier in the fall. Any fertilizer may be used according to label directions. Cool temperatures or long nights are required to induce blooming. The plants bloom when given night temperatures near 55°F and day temperatures below 65°F.
Flowering is related to day length and nighttime temperatures. The temperature range for flower bud development is between 55° and 60°F for a period of six weeks. If the temperatures remain in this range, they will develop buds regardless of day length. If the temperature in your home gets above the required range, the plant will need 13 hours of uninterrupted darkness each night. This can be done by placing the plant in a completely dark room or by covering it each night with a dark piece of cloth. The plant can also be kept in total darkness until the bud develops. For holiday blooms, this usually means in late September to mid-October.
During flower bud formation, stop fertilizing and only water enough to keep the leaves from becoming shriveled. Once buds do form, you can keep the plant in normal light and temperatures. Keep it evenly moist and fertilize it every other week with a mild fertilizer solution.
General Schedule of Ideal Life of Christmas Cactus
January – Flowering
February to March – Resting (55°F, infrequent watering)
April to May – Water thoroughly when potting mix begins to dry out.
June to August – Place outdoors in a shady spot.
September to October – Plant appears to flower. Reduce daylight hours. Keep on the dry side and cool (55 to 60°F) until flower buds form, then increase water and temperature.
November to December – Flowering. Water normally. Temperature no less than 55°F.