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Christmas Cactus light Requirements: A Complete Guide

Christmas Cactus makes a perfect celebratory plant for its vibrant blossoms that brighten up your home every holiday season.

However, if the plant leaves are suddenly bleaching or losing their signature green color, you should know that it is under light stress.

You heard it right! They produce signature pink or lilac-colored blossoms, provided with appropriate lighting.

Christmas Cactus requires 8 hours of indirect sunlight (Over 10 hours in the case of artificial lighting) and 16 hours of darkness to produce magnificent blossoms and maintain healthy-looking foliage. Place the plant near East or North-facing windows to meet their light requirement.

Christmas Cactus Flower
Christmas Cactus Flower (Source: Pixabay)

Anything more or less will affect food production, leading to discolored leaves, dropping blossoms, and other problems.

Read on to find out how to identify lighting problems with your Christmas Cactus and find ways to treat or prevent them early.

Overview of Christmas Cactus

Christmas Cactus, also known as Christmas Cacti, is known for its rich, bright flowers and lush green leaves, which makes them one of the most holiday-gifted plants.

Why the name Christmas cactus? These epiphytic succulents begin flowering in November and last until February, coinciding with the holiday season.

Fun Fact: Did you know these plants only flower from April to May in their natural habitat and bear no resemblance to Christmas?

However, do not be confused by similar-looking plants sold as Christmas cacti.

How to identify Holiday cactus
How to identify Holiday cactus (Source: Garden Gate magazine)

The true Christmas Cactus will have stems arching downwards with a closed habit, and the stem margins will be rounded with tiny visible points (nubs).

Nonetheless, they make beautiful houseplants that are widely grown and gifted in many United States households.

Here is the overview of Christmas Cactus.

FactorsSpecification
Scientific nameHybrid Schlumbergera ×buckleyi
Common nameChristmas Cactus, Christmas Cacti, holiday cactus, zygocactus
Genus/FamiliaSchlumbergera (Zygocactus)/Cactaceae
NativeSoutheast Coastal Brazil
USDA Zone9-11
For both indoor and outdoor plant
Temperature60-70°F (15-21°C)
Life-spanIndefinite when provided with ideal care
Growth6-12 inches tall and 12-24 inches wide
Grown forGrown for cerise (red) flowers but are also found in different colors such as pink, yellow, or orange
Foliage colorGreen
Blossom TimeNovember to February
Blossom PatternTubular flowers not bigger than a few inches
FruitPollinated flowers produce blueberry-like fruit full of tiny black seeds
Soil acidityAcidic (5.5-6.2 pH)
ToxicityNon-Toxic to humans and pets

The real struggle with the plant begins during its blooming period when the sunlight is at its minimum due to a change in the earth’s tilt.

Therefore, artificial grow light may be handy to ensure the plant blossoms advertently.

Note: The plant is not a true Cactus. In fact, it is not even quite as drought tolerant as the Cacti, so do not treat it as one.

How Much Light Does Christmas Cactus Need?

Christmas Cactus is a pan-tropical plant that thrives in shades of large rocks and trees.

When grown as a houseplant, Christmas Cactus would naturally thrive in indirect sunlight for 8 hours a day with 16 hours of complete darkness to set buds for flowering.

However, ample lighting plays a vital role in developing blossoms; hence avoid keeping the plant in low-light conditions.

A few hours of early morning or late noon sun will do wonders to the plant.

In the summer, Christmas cacti can be moved outside, but they need to be kept in a partially to completely shaded area. The leaves may burn in direct sunlight.

Alternatively, keep these plants under the appropriate grow light with a color range of 400–700 nm to mimic natural light.

An emphasis on red (for flowering), blue (for green foliage), yellow, and green wavebands will help boost plant development.

As the plant blossoms in fall and winter, you must keep them under LED grow light to ensure they develop signature holiday flowers.

A light-deprived plant may do well only for a few weeks before exhibiting low-light problems and ultimately dying.

Similarly, it requires a warm temperature and 50-60% humidity to attain healthy-looking leaves.

However, be wary about keeping them outdoors because direct sunlight will scorch the leaves and lead to bleaching.

Christmas cactus under duress
Christmas cactus under duress (Source: Ask Extension)

You can consider growing them outdoors only if you live in a warm climate, USDA zone 9 or above.

Because Christmas Cactus is not cold hardy, it may begin to wilt at the onset of low temperatures.

Signs of Light Deprived Christmas Cactus

The signs of light-deprived Christmas Cactus are less vivid than the light-saturated plant because the plant usually thrives in low light.

In fact, the blossoms need the common light condition to develop.

However, it does not mean you should deprive the plant of much-needed indirect sunlight.

One of the earliest indications of a faltering Christmas Cactus due to lack of sunlight is the loss of green pigmentation on the leaves.

Here are some tell-tale signs of the severely light-deprived Christmas cactus plant.

  • Discolored leaves due to lack of chlorophyll
  • Yellowing with light green or pale foliage texture
  • Leggy growth with gaps between each leaf (etiolation)
  • Dropping buds and leaves
  • Thinning top growth
  • Slowed growth

Signs of Light Saturated Christmas Cactus

The light-saturated Christmas Cactus is too quick to show signs of problems.

Although it enjoys ample indirect sunlight, too much exposure can affect the healthy leaf and flower growth.

Do not be surprised when your Christmas cactus appears bleached, which has to do with excess UV exposure and heat.

Here are some tell-tale signs of the light-saturated plant.

  • Bleached leaf (green pigments are replaced by white texture)
  • Leaves turning red or pink
  • Sunburnt leaves
  • Yellowing edges on leaves
  • Browning spots on leaves
  • Immature flowering

Note: A sun-exposed Christmas Cactus is likelier to wilt and die than its light-deprived counterpart.

How to Ensure Optimum Light for Christmas Cactus?

Christmas Cactus hails from the Brazilian rainforest that provides ample sunlight and shade.

You should mimic similar conditions at home to ensure a healthy plant.

1. Plant Location

Introduce them to an ideal location around the house that receives dappled sunlight for at least 8-hours a day.

The east-facing window is best for the plant where they can enjoy 4-hours of morning sunlight.

Alternatively, you can keep them in the south-facing window at least three feet away to avoid direct sunlight.

Bright, indirect sunlight
An illustration of the bright, indirect sunlight (Source: Mr Houseplant YouTube)

Some Christmas Cactus is conditioned to grow on patio and garden, where the noon temperature tends to go above 80°F.

However, remember to gradually expose the plant to direct sunlight for a few hours every day before permanently moving them outdoors.

As per the rule, place the plant in low-intensity sunlight two hours a day for over four days before moving them.

Look for a garden location with gentle morning sunlight or dappled afternoon light.

2. Light Intensity         

Christmas Cactus grows best in the dappled light of 65 to 80%, approximately 1500 to 3000 FC.

As a flowering plant, it naturally prefers the higher light intensity, usually 2500-3000, during the blossoming period.

Anything over 4000 Foot Candles will burn the plant leaves. Direct sunlight has an intensity of 10,000 FC, making it quite harmful.

Here is a small table describing the light intensity and exposure provided.

Light IntensityFootcandlesLight Exposure
Low-medium 25-400North-facing window
Medium-Bright500East-west facing window
Bright-High Light500-1000South-facing window
Direct Sunlight+10004-6 hours of direct sunlight

Although the plant does well in low light, the flowering will falter due to a lack of proper light intensity and color spectrum.

Ensure the location has ample relative humidity, over 50% when exposed to high light intensity.

3. Light Duration

The lighting duration will depend on the plant’s stage; germination, flowering period, and stasis.

Generally, Christmas Cactus would require 10-14 hours of lighting to germinate, about 8 hours to produce blossoms, and even less when it reaches stasis (maturity).

Remember to provide anywhere from 6-8 hours of dappled sunlight every day, especially near fall and winter, to boost the growth of blossoms.

Light duration throughout the day (Source: MakeaGif)
Light duration throughout the day (Source: MakeaGif)

When grown under artificial light, provide 10 hours of lighting and 14 hours of darkness.

You can increase the amount of dark, especially when they are amid the blossoming season.

4. Light Quality

The light quality is crucial for Christmas Cactus growth, especially when you live in a colder USDA zone.

The lack of sunlight can be compensated with appropriate grow light.

When keeping them under grow light, use full-spectrum lighting that combines red and blue colors to induce healthy growth.

The best type of light you can give your Christmas Cactus is light with a color temperature of 6000K for optimum growth, healthy leaves, and flowering.

Light intensity and spectrum
Light intensity and spectrum required for green plants (Source: Tu-Bu)

Smaller amounts of green, yellow, and infrared wavelengths will help boost photosynthesis.

Use our light color and spectrum chart to determine the appropriate light quality for your Christmas cactus.

Does Christmas Cactus Grow in Artificial Light?

The Christmas Cactus quickly adapts to low light conditions but will readily produce blooms when exposed to sunlight.

Ensure to keep them in a location with indirect sunlight during the day and complete darkness at night when blossoming, usually fall and winter.

If not possible, compensate indirect sunlight with artificial grow light for 10-14 hours a day followed by complete darkness.

The commercial UV LED grow lights will be an appropriate choice because they are designed based on each plant’s lighting requirement.

However, the light intensity may become an issue with artificial lighting when you keep your plant too close to the light source.

Grow LightsDistance
HID Grow Lights (400W)12”-19” away from the plant
HID Grow Lights (600W)14”-25” away from the plant
LED Grow Lights (240-400W)16”-30” away from the plant
LED Grow Lights (450-550W)20”-30” away from the plant
CFL (200W)6”-10” away from the plant

Exposing them to high-intensity light, over 700nm, to compensate for low lighting may also be harmful as it can quickly dehydrate the plant.

Find the light setting between 400-700nm kept at least 12-19 inches away from the plant for 10-14 hours daily.

Remember, the Christmas Cactus requires long, uninterrupted dark periods to produce healthy blossoms.

LED LightsFeaturesImage
SPIDER FARMER SF-2000 (200 Watts)Hydroponic grow lamp with dimmable quality provides full-spectrum lighting between 660nm to 760nm.
MARS HYDRO TS-1000 Led Grow LightA hydroponic grow light provides 3x3-ft coverage and offers 660-665nm Red IR/3200-4200Knm/5200-6800Knm, close to natural light.
BESTVA Led Grow Light (2000 Watts)Hydroponic grow lamp with 5x4-ft coverage with options for VEG mode for vegging and BLOOM mode for flowering.
MAXSISUN PB4000 (400 Watts)Hydroponic grow lamp with 4x4-ft coverage that provides between 660nm to 730nm color spectrum.

Tips to Maintain Optimal Lighting Condition 

Here are a few proven tips to ensure optimal lighting for your Christmas Cactus.

  • The plant’s growth potential depends on the location it grows. Find out the lighting duration and intensity for your region.
  • Know that your plant is suffering from over or underlighting when it begins exhibiting the earliest signs like yellowing, red or pink of leaves.
  • Add a sheer curtain or blind on the window to filter high-intensity sunlight; otherwise, move your plant a few feet back.
  • The light and temperature should go hand in hand to ensure healthy green foliage and blossoms.
  • You should naturally increase sunlight in spring and autumn but cut down in fall and winter to induce blossoms.
Christmas Cactus
Christmas Cactus (Source: Pinterest)

Conclusion

Christmas Cactus is a go-to species when it comes to easy-to-maintain houseplant plants. On top of that, they make a wonderful holiday gift.

It all comes down to optimal lighting to ensure your Christmas Cactus keeps blossoming every successive year.

The plant stressed from inappropriate lighting will look unhealthy, fail to blossom, and may soon die.

Drop in your comment to let us know what worked for your Christmas cactus.

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