The name is misleading. A Christmas cactus is not a desert plant. It grows in the mountain forests of Brazil, perched in the branches of trees or in pockets of leaf litter on rocks. That tells you a lot about the soil it wants.
Epiphyte, not desert cactus
Christmas cactus (Schlumbergera) is an epiphyte. Its roots cling to bark and take in moisture from rain and humid air, but they also dry out between showers. So its roots expect two things: air, and a little moisture that does not hang around.
A desert cactus mix with a lot of sand and grit is too dry and too heavy for it. Regular potting soil is too wet and too dense. What works sits in the middle: a chunky, airy mix that holds a bit of water.
What to look for in the mix
- Bark. Medium bark gives epiphytic roots air and something to grip.
- Pumice and perlite. These keep the mix open so water drains.
- Some coco coir. It holds a little moisture, so the mix does not go bone dry in a day.
- No heavy fine soil. It compacts and suffocates the roots.
If you squeeze a damp handful and it falls apart, it is the right texture.
A simple blend
A good approach is to start with our Succulent & Cactus Mix and add bark. Mix roughly 2 parts Succulent & Cactus Mix to 1 part Orchid Mix. That gives you pumice, coco and perlite from the first, and the fir bark, charcoal and coco chips from the second.
It is a rough ratio, not a lab recipe. If your plant sits in a dry, heated room and the mix dries too fast, add a little more succulent mix. If it stays damp too long, add a little more orchid mix.
You can also build a similar blend from bulk bags of bark, perlite and coir. The trade-off is quantity: those bags are big, and one Christmas cactus needs very little. Two small bags of ready-mixed material is simpler.
Signs of the wrong soil
- Soil is still wet a week after watering.
- Segments (the flat leaf-like pieces) turn limp or translucent.
- The base of the plant turns dark or soft.
- Flower buds drop before opening. This has several causes, including drafts and moving the plant, but constant wetness is one of them.
- The mix has turned to hard dust that water runs straight through.
How to repot a Christmas cactus
Wait until after blooming. Repotting while it has buds can make it drop them.
- Choose a pot only 2 to 3 cm wider than the current one. Christmas cactus flowers best when slightly root-bound, and a big pot holds too much wet mix.
- Make sure the pot has a drainage hole.
- Slide the plant out. Gently loosen the old mix from the roots, and trim off any that are brown and mushy.
- Add a layer of fresh mix, set the plant at the same depth as before and fill in around the roots.
- Press lightly and wait about a week before watering, so any damaged roots can heal.
- After that, water when the top 2 to 3 cm feels dry.
Each mix page has a “How much do I need?” calculator. For a small Christmas cactus pot, it will usually come out to well under one bag.
Care notes that go with the soil
Water more often than you would a desert cactus, but let excess drain, and empty the saucer. Bright, indirect light suits it. Because the mix has no fertilizer, you will want to use a houseplant fertilizer during spring and summer.
Christmas cactus needs long nights and cool temperatures in autumn to set buds. That is about light and temperature, not about soil, but a healthy root system makes it easier for the plant to cope with it.
Thanksgiving, Christmas and Easter cactus
The plants sold as Christmas cactus are often a related plant, the Thanksgiving cactus, which blooms a little earlier. The leaf segments are the quick way to tell them apart: Christmas cactus segments have rounded, scalloped edges, while Thanksgiving cactus segments have pointed, claw-like tips. Their soil needs are the same, so the same blend works for both. Easter cactus is a close relative and also grows well in this mix.
Common mistakes with Christmas cactus soil
Treating it like a desert cactus is the big one. People hear the word cactus, give it sand and rare watering, and the segments shrivel. Equally common is the opposite: dense potting soil and constant watering, which leads to rot.
Another is repotting too often or into a large pot. These plants flower best with roots that are a little crowded. A pot that is too big means more wet mix and fewer blooms.
Keep the mix evenly lightly moist during the growing season and a bit drier in the weeks before budding. If the plant has sat in the same mix for several years and the bark has turned to fine dust, refresh it, even if the pot size stays the same.
Where to get the mixes
Both mixes come in light 3-litre bags and ship across Canada by Canada Post, except Quebec for now. Check the shipping page for rates. If you also grow other plants, our guide to the best soil for indoor plants shows which mix goes with which plant.
