The Christmas cactus is a tropical plant that blooms in the northern hemisphere during winter. Fertilizing a Christmas cactus is essential for its growth and blooming. But you must feed it at the right time with the right type of fertilizer.
Christmas cacti should be fertilized every 2-4 weeks during the growing season (spring and summer) with a balanced, water-soluble fertilizer such as 20-20-20 or 10-10-10 diluted to half-strength.
It’s important to note that Christmas cactus has higher requirements for magnesium than most houseplants. Apply Epsom salt (magnesium sulfate) monthly during the growing season but not the same week as the regular fertilizer.
When to fertilize Christmas cactus
Christmas cactus is native to Brazil’s rainforests, where they grow as epiphytes – on rocks or branches of other trees. In their native home, these plants obtain nutrients from decomposing plant materials like leaves and tree bark.
This plant uses much energy for buds and flower production when blooming. If you decide to keep the plant for the next blooming cycle, you must fertilize it to replenish its nutrient supply. This will also help you grow a bigger Christmas cactus without any difficulty.
Timing is very important in fertilizing a Christmas cactus. Fertilization should be done during active growth in spring and summer. Cut back on fertilizing schedule during fall and winter to encourage the cactus to bloom.
Fertilizing a Christmas cactus in fall or winter may prevent flower buds from forming. Feeding a blooming cactus also makes the flower buds fall off or not open.
How to Fertilize Christmas cactus
Fertilizers have different salt compositions, which can burn plants if used improperly. Christmas cactus prefers a balanced houseplant fertilizer such as 10-10-10 or 20-20-20 diluted to half-strength or as the manufacturer directs.
The all-purpose formulation has Nitrogen (N), Potassium (K), and Phosphorous (P) in equal proportions, ideal for all-around plant growth. It is important to use it in liquid form for easy and even absorption of nutrients by the plant.
Granular formulations aren’t effective on houseplants as they take time to dissolve and absorb. They may also create salt buildup in the soil.
Fertilize your Christmas cactus monthly with liquid houseplant fertilizer (10-10-10 or 20-20-20) from when new growth starts in spring to late summer. Dilute your fertilizer with twice as much water as recommended on the package to form a half-strength solution.
Epsom Salt (Magnesium Sulphate)
Christmas cacti also require plenty of magnesium, which is very useful in producing Chlorophyll – the green pigment plants use to manufacture food during photosynthesis.
To meet the plant’s magnesium need, apply Epsom salt (magnesium sulfate) monthly, diluted at 1 teaspoon per gallon of water, but not the same week you applied a fertilizer.
Christmas cacti can also benefit from homemade fertilizers, such as coffee grounds and well-decomposed compost. Simply provide one tablespoon at a time and spread it into a thin layer 2 to 3 inches from the stem of the cactus. Always water after applying any fertilizer.
Other care requirements for Christmas cactus
Besides fertilizing, the following are important care requirements for a Christmas cactus:
1. Yearly pruning
You need to prune your Christmas cactus as soon as the blooming ends. This helps the plant to grow bushier for more blooms in the future. When pruning, you might also decide to root the cuttings for more new plants you can gift your friends and family.
2. Correct watering
Water the Christmas cactus only when the top 1 inch of the soil feels dry. Overwatering may result in root rot – a condition caused when roots suffocate and die. Christmas cactus root rot is difficult to treat; you can only remove the damaged roots and repot the plant.
This plant also enjoys high humidity levels ranging from 50 – 60%. You’ll need to boost humidity levels when the air is dry in your home. Use a humidifier or place the plant on a pebble tray half-filled with water. Ensure the pot is not in direct contact with the water.
3. Indirect sunlight
If you wish, you may move your plant outdoors during summer, but too much direct sunlight will scorch the stems. Place the plant under a tree or on your porch outdoors
Generally, a Christmas cactus prefers bright indirect light. Always place it near a north or east-facing window for the light. You may also place it under grow lights. Ideally, a daytime temperature of 70°F and an evening temperature of 60-65°F is preferred.
4. Control pests
Watch for pests such as mealybugs and scale insects that punch and suck sap from the stems. Pests are also vectors for fungal infections. It’s important to regularly monitor the plant for signs of pests and provide treatment.
You may clean the cactus using a solution of isopropyl alcohol or kill the bugs with insecticidal soap or agricultural oil like neem. Make sure to use it as directed by the manufacturer.
5. Repot if needed
To enjoy the winter blooms even for more years, repot the Christmas cactus after every two to three years. Use well-draining soil formulated for succulents and a slightly bigger pot with a drainage hole at the bottom.
You may divide the Christmas cactus if it grows too big to prevent the stems from splitting. The additional plants can also be gifted to friends and family members.
The Christmas cactus makes a perfect holiday houseplant that rewards with blooms in the dead of winter. Fertilization during growth helps in boosting growth and flower production. Make sure to grow the plant in a bright spot away from direct sunlight and water only when the top inch of the soil feels dry.
- Clemson University Cooperative Extension: THANKSGIVING & CHRISTMAS CACTI
- North Carolina Cooperative Extension: Christmas Cactus Care
- N.C Department of Agriculture: A Homeowner’s Guide to Fertilizer
My name is Diane M Lewik, and I am the founder of this website. I am a degree holder in plant biology from the University of California – Berkeley. Over years, I have cultivated a vast collection of succulents and I have learned a great deal about how to grow and care for these unique plants.