How to Get a Christmas Cactus to Bloom: Temperature and Light

The Christmas cactus is loved for bringing color to the winter with its flowers. So you bought a Christmas cactus that had numerous flower buds in its first year. However, the plant does not bloom forever and loses its blooming splendor as the days grow longer.

This does not mean that the Christmas cactus has to go without blooming. Without much effort, it can survive the summer without trouble and bloom again in the winter. So how to get a Christmas cactus to bloom?

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 (Schlumbergera x buckleyi) bloom successfully.

How to Get a Christmas Cactus to Bloom

Christmas cacti flower between November and January. They require a short rest period before and after flowering. When they are dormant, they do not need much water or fertilizer. In the summer i.e. after flowering, these care measures are increasingly important for Christmas cactus plants.

This refers to a period of rest without water and fertilizer after flowering for the Christmas cactus. It is important to water the Christmas cactus more frequently between April and September, and during the flowering period. However, you should never let it become waterlogged. Use lime-free water when watering.

The Christmas cactus should also be fertilized with a liquid fertilizer every four weeks during its growth phase. As an example, Miracle-Gro Succulent Plant Food will produce resistant and healthy shoots for the holiday cactus because it has a favorable ratio of nitrogen and potassium. In addition, it can be easily administered via irrigation water and the nutrients are directly available to the plant. Summer is also the most suitable time for repotting the Christmas cactus.

The tropical cactus can also be grown outdoors in the summer if there is no threat of frost. It prefers semi-shady locations, as it does not tolerate direct sunlight well. You can let the plant spend the summer outdoors, protected from the sun. However, planting it outside isn’t a good idea because it has to return inside at temperatures below 50°F (10°C).

To get a Christmas cactus to bloom in winter, follow these care instructions in summer:

• No fertilizer or water during the dormant period before and after flowering.
• Whenever new growth appears, increase watering accordingly and restart liquid fertilization every 4 weeks.
• The Christmas cactus can be moved outside for the summer if the temperature is not below 50°F (10°C).
• Christmas cactus prefers partial shade – full sun is not ideal.
• The plant must be moved indoors once the temperature falls below 50°F (10°C).

How Do You Stimulate a Christmas Cactus to Bloom?

Getting the Christmas cactus to bloom takes a crucial period of preparation when it gets cooler outside again. In this case, care and location, as well as the length of the day, are crucial. As of October, watering should be significantly reduced.

It is advisable to have slightly cooler temperatures, around 59°F (15°C), to promote the formation of flower buds. However, it shouldn’t be colder than 50°F (10°C), because then no buds are formed. It shouldn’t be too warm either, since temperatures around 68°F (20°C) can cause no buds to form.

The Christmas cactus is a so-called short-day plant, which means it must not get too much light before flowering. From October, the plant should experience a maximum day length of nine hours. In other words, you can place the cactus in a room with long periods of darkness. If the plant is on the windowsill, you can cover it with a box so that no light shines through.

During the night phase, you should ensure that no light reaches the plant in order to induce flowering. A brief light exposure will disrupt the formation of buds of the Christmas cactus. Therefore, to ensure a rich flowering, you should keep light out of the plant completely at night. Once the first buds have formed, you can move the Christmas cactus to an area around 68°F (20°C) that is brighter and warmer to accelerate the flowering process.

At a glance: What triggers blooming in Christmas cactus?

• Flower development is influenced by the interaction between temperature and day length.
• In October, dormancy begins, which means lower temperatures, reduced watering, and shorter days to encourage flowering.
• Regardless of day length, temperatures around 50°F (10°C) hinder flower development.
• Temperatures above 72°F (22°C) only inhibit flower formation.
• Short days (maximum 9 hours) with temperatures around 59°F (15°C) work best.
• Make sure that no light source provides light for more than nine hours, for example, by placing cardboard on the windowsill.
• When flower buds form, a bright location and temperatures around 68°F (20°C) are ideal for further development.
• Water sparingly before and after flowering, and keep only slightly moist during flowering.

Why Can’t I Get My Christmas Cactus to Bloom?

If you have followed all the tips, but your Christmas cactus does not bloom, it means that one or more mistakes have been made that prevent the Christmas cactus from blooming. So let’s take a second look at what might have gone wrong if the Christmas cactus simply refuses to produce flower buds:

Why is my Christmas cactus not budding?

• Ambient temperature too high (above 72°F or 22°C)
• Ambient temperature too low (around 50°F or 10°C)
• No short-day conditions of a maximum of 9 hours of daylight – not darkened or interfering light
• Stress due to wrong watering: watered too much and maybe even caused waterlogging

Why do Christmas cactus buds fall off before blooming?

Having developed buds does not necessarily mean that the Christmas cactus will bloom to its fullest capacity. It is in a very sensitive phase and if certain factors are not optimal, it can also simply shed its formed flower buds. Various factors can lead to the Christmas cactus losing buds.

• Too little light after the development of the flower buds
• Temperatures that are too cool after planting the flower buds – at least 59°F (15°C) is recommended
• Too generous watering, which leads to waterlogging
• Too little water and drought

Frequently Asked Questions

When should my 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.

Do Christmas cactus need cold to bloom?

In order to set flower buds, Christmas Cactus needs cool days between 60 and 65°F (15 and 18°C), and cool nights between 45 and 55°F (7 and 13°C). Make sure that your plants aren’t near fireplaces or drafts.

When flower buds are forming, 68°F (20°C) is ideal for further development. After the plants have bloomed, avoid sudden temperature changes, as these can cause the flowers to fall off.

Should I water Christmas cactus while budding and about to bloom?

As the Christmas cactus is budding and about to bloom, you should water it sparingly and mist it frequently. Do not overwater or underwater as this will cause buds to fall off before blooming.

How much water should I give my Christmas cactus to bloom?

For your Christmas cactus to bloom, only water when the topmost layer of soil is dry to the touch, about 1 inch (2.5 cm). It is possible to increase watering during blooming, but the amount will depend on the plant’s current light conditions, temperature, and humidity levels.

How long does it take for Christmas cactus buds to bloom?

Christmas cactus blooms usually appear within 12 weeks (or less) after buds form.

When should you put a Christmas cactus in the dark?

You should put a Christmas cactus in the dark from October until the formation of the first buds. Its day should not exceed nine hours.

How often can you force a Christmas cactus to bloom?

You can force a Christmas cactus to bloom twice a year, in winter and in spring. To do so, provide short daylight hours (maximum 9 hours), keep the temperature around 59°F (15°C) and water sparingly for at least six to eight weeks or until the formation of the first buds.

What temperature is too cold for Christmas cactus?

Christmas cactus can tolerate temperatures as low as 50°F (10°C), but cannot endure freezing temperatures. The ideal temperature range for the Christmas cactus is between 70°F and 80°F (21°C to 27°C).

Can Christmas cactus tolerate 40 degrees?

In the winter, Christmas cactus may be able to withstand night temperatures down into the 40s. Don’t keep it outdoors if the temperature dips below 40 degrees F at night.

Where is the best place to put a Christmas cactus?

A bright bathroom or kitchen is an excellent place to put a Christmas cactus since they prefer a more humid environment. During the summer, you can place Christmas cacti in a shady spot in your garden or on an unheated porch until the temperature drops below 50°F (10°C). Avoid direct sunlight on them.

For more tips on how to propagate, prune and care for your Christmas cactus, check out our related articles.