The Christmas cactus brings color to winter with its flowers. But how can you get it to bloom?
In the first year you buy the Christmas cactus (Schlumbergera x buckleyi) with numerous flower buds. However, the cactus plant (Cactaceae) does not flower permanently and loses its flowering power with the longer days. But this does not mean that the Christmas cactus has to give way. It can be brought through the summer well and without much effort and bloom again in the winter. First of all, of course, proper care until winter is the be-all and end-all. Ultimately, however, the interplay between the right temperature and the right lighting conditions is the decisive factor to make the Christmas cactus bloom successfully.
Christmas cactus: The right care in summer
After flowering is before flowering – so also in the case of the perennarian Christmas cactus. After flowering, the Christmas cactus first treats itself to a small resting phase. The watering must be reduced and the fertilization is still suspended throughout the flowering. If the Christmas cactus is to be given a larger pot, now is the right time for repotting. Finally, the Christmas cactus will herald the new growth season with the new shoot. The watering must be increased and the fertilization (approximately every four weeks with a full nutrient fertilizer) must be resumed.
If there is no more threat of frost, the winter cactus can also spend the summer outdoors. It feels most comfortable in a partially shaded location, as it does not tolerate direct sunlight so well. The Christmas cactus spends the summer happily outdoors. However, it is not worth planting out, because at temperatures below 10°C (50°F) it has to move back into the house anyway.
In general, the following applies to the optimal care of the Christmas cactus in summer:
- After flowering, dormancy is a good time to repot
- With new shoots, increase irrigation as required and start fertilizing again (every 4 weeks with full nutrient fertilizer)
- As soon as the temperatures allow it, the Christmas cactus can move outside for the summer (preferably no colder than 10°C or 50°F)
- Partially shaded location – the Christmas cactus cannot tolerate full sun
- Do not plant out the Christmas cactus
- As soon as the temperatures drop, it has to move back into the house
How to get a Christmas cactus to bloom
As soon as the Christmas cactus moves into the house due to the falling temperatures, the crucial phase in preparation for flowering begins slowly. The factors and day length play a decisive role here. Irrigation should be significantly reduced from October. Slightly cooler temperatures around 15°C (59°F) favor the formation of the desired flowers.
In addition, the Christmas cactus is a so-called short-day plant. It is best if the plant experiences a maximum day length of 9 hours for at least four weeks. So you have the choice whether to place the cactus in a room where there is no interfering light for too long or to always darken it. This works, for example, by placing a cardboard box over the plant on the windowsill and guaranteeing that no light shines through.
If the temperature is too cool (around 10°C or 50°F), the length of the day no longer plays a role in the formation of flowers, but then the formation of the buds is generally more difficult. Temperatures above 22°C (72°F) completely prevent flower formation. When the flower buds begin to develop, the Christmas cactus can also move to a brighter and warmer location. This accelerates the further development of the flowers.
In general, the flowering of the Christmas cactus can be specifically influenced by the following factors:
- Interaction between temperature and length of day determines the formation of flowers
- From October resting phase with lower temperatures, significantly reduce watering and shorten day length to encourage flower formation
- Temperatures around 10°C (50°F) : difficult flower formation regardless of the length of the day
- Temperatures over 22°C (72°F) : flower formation usually prevented
- OPTIMAL: Temperatures around 15°C (59°F) and short days (maximum day length of 9 hours)
- For example, darken the window sill with cardboard or make sure that no light sources provide more than 9 hours of light
- As soon as the flower buds develop: a brighter location and optimal temperatures of around 20°C (68°F) promote further development
- Adjust watering as required
When do Christmas cactus bloom?
The Christmas cactus is not wrongly named. Its bloom period falls exactly around Christmas. The flowers, which appear in many colors, bloom for several days.
The flowering time of the Christmas cactus begins at the end of November and lasts until January, depending on the location and care. Six weeks of flowering are not uncommon. The individual flowers bloom for several days.
How often does a Christmas cactus bloom?
Christmas cactus blooms once a year around Christmas. However, there are a few hybrid forms of the Christmas cactus that will produce a second flowering period in February.
Why isn't my Christmas cactus blooming?
Errors can occur with some factors that can prevent the Christmas cactus from blooming. So let's look again from the other angle and list what could have gone wrong if the Christmas cactus simply doesn't want to produce flower buds:
- Ambient temperature too high (over 22°C or 72°F)
- Ambient temperature too low (around 10°C or 50°F)
- No short-day conditions of a maximum of 9 hours of daylight – not darkened or interfering light
- Stress due to incorrect watering: watering too much and maybe even causing waterlogging
When the Christmas cactus has formed its flowers, it does not mean that it will develop its full flowering power. It is in a very sensitive phase and if certain factors are not optimal, it can easily shed its developed flower buds. The following causes can be responsible for the falling of the Christmas cactus buds:
- Too little light after the flower buds have developed
- Temperatures that are too cool after planting the flower buds – at least 15°C (59°F) is recommended
- Too generous watering that leads to waterlogging
- Insufficient watering and drought