In this article I outline the light requirements of the christmas cactus. Although all plants require light to grow it is especially important to provide your christmas cactus with the correct lighting. Incorrect lighting for a christmas cactus will, at best, prevent it from blooming, and at worst it will damage the plant and may even lead to its death. So, it is important to follow the advice given below if you want your christmas cactus to remain healthy for decades and to consistently flower.
Christmas cactus light requirements
A christmas cactus, like all cacti, has very specific light requirements. Being a tropical plant that naturally grows in warm habitats on shaded areas of trees and in rocky formations this cactus requires less sun than many other popular succulent houseplants. As you will see when you get to the section on christmas cactus temperature tolerances, the temperatures required to cultivate christmas cactus make it unsuitable as an outdoor yard plant in most areas of the USA.
The christmas cactus, scientific name Schlumbergera bridgessii, grows naturally in the coastal areas of south-eastern Brazil. This particular cacti plant is a member of the broader succulent family Schlumbergera. Other species of this succulent family include the thanksgiving cactus, holiday cactus, crab cactus and the easter cactus.
As this particular cacti species grows in mostly shaded areas in a tropical climate it has very specific lighting needs. Let’s look at those now.
How much light does christmas cactus need?
So how much light do you need to provide for your christmas cactus plant?
Christmas cactus requires at least 8 hours of strong indirect sunlight per day. During the growth stage you can provide christmas cactus with up to 12 hours of light per day. However, christmas cactus also require a minimum of 12 hours of complete darkness each day in order to bloom.
Although the christmas cactus will adapt to low light levels, as it naturally grows in shady areas, you will never get the best out of your christmas cactus houseplant if you leave it in a gloomy or totally shaded environment.
Semi-shade is fine for christmas cactus if the plant also receives limited direct sunlight. However many houseplant owners, myself included, will opt for a location that provides only indirect light as this alleviates the need to ensure the plant is not getting too much sun or too much shade.
You should also note that christmas cactus requires at least 12 hours of full darkness per day. So, although during those daylight hours when the plant is receiving light it should be getting strong indirect light, you must also ensure the plant is allowed to rest at night.
If these cacti plants do not get at least 8 hours of good indirect light per day along with at least 12 hours of complete darkness at night they will fail to bloom. Be sure to read our article how to make christmas cactus bloom.
Does christmas cactus need sun?
So now that you know that a christmas cactus plant needs at least 8 hours of light per day you will likely want to know what type of light is best for the plant. Should you place these cacti is direct or indirect light?
Christmas cactus do not need full sun. In fact the foliage will burn if the plant is left for prolonged periods in strong direct sunlight. Although tolerant of short periods of direct sun if it is combined with semi-shade, christmas cactus houseplants are easiest to grow in indirect sunlight.
Although you can place a christmas cactus in a window to ensure it gets good light you should avoid sun-facing windows. I will usually place christmas cacti plants by a north-facing window as this will provide the best type of indirect light. I avoid south-facing windows as placing a christmas cactus there will provide the plant with too much direct sun that will likely lead to leaf burn.
If in doubt about which window is best for your plant simply place it in a well lighted area of your home that does not get direct sunlight.
I have one christmas cactus situated underneath, but to the side of, a skylight in my kitchen. Although the sun shines strongly through the skylight on clear sky days, the rays never reach the plant due to its slightly offset position. However, the skylight ensures the entire area is well lit thus making the corresponding indirect-lighted area an ideal location for this particular cacti.
Christmas cactus shade or sun?
So, with a christmas cactus growing in shaded areas in its natural habitat which is best for a christmas cactus houseplant, shade or sun?
Christmas cactus houseplants will grow best in neither shade nor sun. Although christmas cactus grow on trees and rocks in shady areas in their natural tropical habitat, it is best to place a christmas cactus houseplant in strong indirect light away from both shaded areas and also away from strong direct sunlight. Direct sun will burn the leaves and too much shade will not provide enough light for the plant to bloom.
The reason I advocate indirect light for christmas cactus houseplants rather than the type of semi-shade the plant naturally grows in, is because this is difficult to replicate. Placing a christmas cactus in an area that gets some direct sunlight during the day, with the rest of the daylight hours being in shade, can be difficult to maintain.
With changing seasons an area that gets 1 or 2 hours of direct light per day, with the remaining hours providing shade, can quickly change to no hours of direct sunlight and complete shade. The opposite can also happen where the plant is getting too much direct light and not enough shade.
Therefore to maintain the correct balance between direct light and shade you will have to move the cactus constantly. It is much easier to simply place the plant in a permanent location that gets only good indirect light.
When taking this approach, as a rule-of-thumb, you should aim to give your christmas cactus at least 8 hours of good indirect light per day. Although this means the sun should not shine directly on the plant, it does not mean you should place the cactus in a fully shaded area.
Although christmas cactus is tolerant of low light levels it will not thrive, and may never bloom, if it is left continually in shade. Shade should only be used if the plant also receives limited amounts of direct light.
I am sure you can see why it is much easier to simply place the plant in an area that gets only indirect light (though be sure it is good strong indirect light).
Locate your christmas cactus plant in an area that receives at least 8 hours of good indirect light (but no more than 12 hours) and that gets at least 12 hours of complete darkness.
Before I leave this subject I really need to touch on the temperature requirements and the humidity requirements of the christmas cactus as they are strongly linked to the plant’s light needs – after all heat and humidity and directly created by the sun.
Christmas cactus temperature tolerance
Many indoor houseplant owners wonder what the temperature tolerances are for christmas cactus.
Christmas cactus cannot tolerate temperatures lower than 50°F or higher than 90°F. The ideal temperature for christmas cactus is between 65°F – 75°F. The average US home falls into the ideal temperature range for growing christmas cactus as a houseplant.
Christmas cactus is a tropical plant. Its native habitat is both warm and humid and therefore this type of cati loves warm, moist air and temperatures between 65°F – 75°F. As the average home in the US is kept at a constant temperature range between 68°F – 76°F, in both summer and winter, this offers the ideal environment for cultivating christmas cactus.
Christmas cactus plants are not considered to be hardy plants and have limited tolerances for low and high temperatures. Temperatures below 50°F will cause problems for the plant and freezing temperatures below 33°F will kill it.
At the other end of the scale temperatures above 90°F will also negatively affect a christmas cactus especially if the plant is in bloom.
If you can keep your christmas cactus within a temperature range of 65°F – 75°F, and provide it with good humidity levels, then your christmas cactus will thrive and bloom.
How much humidity does a Christmas cactus need?
The natural habitat of the christmas cactus is very different to many other popular succulents grown as houseplants, such as the aloe plant for example which grows in dry air and water-scarce deserts. Where other succulents require dry air and long periods without water the christmas cactus prefers a more moist environment.
Christmas cactus requires high humidity. Humidity levels between 60% and 70% are ideal.
By ensuring the plant is located in a well light area with a constant environmental temperature range between 65°F – 75°F and by placing the plant pot on a tray filled with pebbles and water it is possible to maintain this type of humidity directly around your christmas cactus plant.
As well as using a water tray as described above, you can also plant your cacti in terracotta pots. Return visitors to this website will know that I absolutely love the aesthetic look of terracotta with succulents of all kinds, but this material is actually very beneficial for plants like christmas cactus that require high humidity to thrive.
You see, good quality terracotta pots greatly help to maintain high humidity levels in the localized environment around your plant while simultaneously helping with water drainage.
As I pointed out in our christmas cactus watering guide, succulents (especially cacti), react very badly when left in water-logged soil. Water must be allowed to drain from the soil of succulents or they will develop some very nasty symptoms, the worst of which is root rot.
Hence, christmas cactus requires soil with good drainage and must only be planted in well-draining pots or containers when grown indoors. Terracotta pots greatly help with this, but they go a lot further than just providing good drainage!
Terracotta naturally sweats moisture from the soil. As this moisture seeps through the terracotta material to the outside of the pot it evaporates and creates a localized humid environment directly around the pot. This, therefore, makes terracotta the best option of material for a christmas cactus houseplant. I covered this subject matter in more detail in the article how to grow christmas cactus.
Optimal christmas cactus light conditions
Hopefully you now understand the light needs of your christmas cactus plant. Below I will briefly cover the main points of this article in a bullet list format for reference.
However, if you have not read the entire article I strongly urge you to do so. Do not rely only on the bulleted list as you will miss vital information important for the health of your plant.
4 christmas cactus light requirements:
- Give the plant at least 8 hours of strong indirect light per day.
- Ensure the plant is located in a well lighted area with temperatures between 65°F – 75°F.
- Along with good indirect light ensure the localized environment provides the plant with 50% – 70% humidity using the methods outlined above.
- Be sure the plant gets at least 12 hours of complete darkness each day.
Be sure to read our detailed christmas cactus care guide to get the essential 7 care requirements of this tropical succulent.