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If you love house plants, you may have considered including the Calathea plant in your living spaces. These plants do not need much to grow; no wonder they are popular with many households across the globe.
While Calatheas may not have breathtaking flowers, their dramatic and colorful leaves make them an excellent addition to indoor landscaping and decoration.
You may wonder how much sunlight does a Calathea need? Calathea plants require between 2 to 6 hours of direct sunlight and less than 2 hours deep shade. Even though the plants can grow in low light conditions, they cannot tolerate low humidity, low or inconstant temperatures, wet soil, dry soil, cold drafts, direct sun, or low light. Calathea plants thrive in a well-lit spot with high humidity, moist soil, and steady average room temperature (Source: North Carolina State University)
Too much or too little light can cause problems for your plant, turning the leaves yellow or brown. Calathea plants can brighten your lobbies, offices, interior areas, and meeting rooms. The plant has numerous benefits for houses, workspaces, and offices since they thrive in low-light areas and are easy to care for.
This article highlights details about Calatheas’ light requirement to help you grow healthy plants.
If you are interested in growing Calathea White Star, I encourage you to read this helpful guide: How To Grow And Care For Calathea White Star.
How Much Light Do Calathea Plants Need?
If you have Calathea plants in your house or office, ensure they have the right amount of light to help with food processing and nutrient absorption. Calathea plants need indirect and low to medium filtered light for at least 8 to 10 hours for optimal growth. The plants can still thrive in low-light areas but cannot withstand direct sunlight.
If you are using artificial plant lights, you want to install 15 to 20 watts bulbs or their equivalent. Unlike other house plants that prefer east-facing windows, Calathea thrives in the northern or western window with less exposure to direct sunlight.
Calatheas leaves are delicate and can easily curl or appear droopy when exposed to harsh lighting conditions.
Calatheas Light Requirements
When discussing Calatheas light requirement, we want to focus on three lighting aspects: light intensity, quality, and duration.
1- Light Intensity
Light intensity measures how much light Calathea leaves can absorb without any adverse effects. Calatheas plant requires enough light to produce enough energy through photosynthesis for good growth.
In the natural habitat, you will find Calathea growing under tall trees. This is not a coincidence; the leaves of the tall trees protect the Calatheas foliage from the harsh direct sunlight. Calathea plants do well with indirect, filtered light, so ensure direct sun rays do not reach your plant pots.
Your Calathea plant can perform well with the indirect light intensity of 1000 foot-candles or 10,000 lux. You can determine the correct measurement using a light meter.
Alternatively, you can use the natural method to test if the spot you want to place the Calathea plant is ideal or not. Consider this procedure that has worked for many households.
- Place a white paper on your preferred spot near the window.
- Hold an object 10 inches away from the paper towards the window.
- If you see a blurred outline on your hand, you know the light intensity is between 10,000 and 15,000 lux, which is perfect for the Calathea.
If you don’t have time to experiment, you can place your plants near the south windows since they often have medium indirect sunlight.
East and west-facing windows receive highly intense sunlight mid-morning and early afternoon. If you want to place your Calathea plant near these windows, you can use curtains or blinds to filter and reduce the light intensity.
The north-facing windows may not be ideal because they result in inadequate sunlight.
2- Light Duration
Light duration is as important as light intensity because it measures how long your Calathea plant should be exposed to indirect sunlight.
Generally, Calathea requires between 8 and 10 hours of indirect sunlight daily. The light should be moderately bright but not direct.
However, since it may not be possible to have 8 hours of sunlight during winter, you can supplement your lighting with grow lights to meet the duration requirement.
Since artificial lighting does not have the same intensity as sunlight, you can extend the duration to 16 hours if you are purely using them without natural lighting.
Remember that the plant also needs 8 hours of darkness for respiration, so ensure you switch off the grow light after 16 hours. The darkness period helps to distribute the energy the plant produces during photosynthesis.
3- Light Quality
You also want to consider light quality for your beautiful plants. This section considers how red, blue, green, and far-red lights affect your Calathea plant.
The red-light spectrum from the light source is suitable for the plant’s photosynthesis, helping with energy production, while the blue-light range enhances Calathea foliage’s rich color.
However, the Ultraviolet rays from direct sunlight can scorch the Calatheas’ luxuriant leaves. You can protect the plant using window films which can block the UV rays but permit the excellent blue and red light to pass to the plant.
4- Your Calathea And Low Light
We know that Calathea cannot tolerate direct light, but what about low light? Calatheas are tropical plants that often grow in South America, meaning they can survive in conditions with low light for a while.
However, persistent low light can be problematic for the Calathea plant. Consider some of the effects of low light on the plant’s well-being.
- Stunted growth due to limited photosynthesis and energy production
- The plant can stop growing altogether
- The leaves fail to fold during the night; they stop praying.
- Long, leggy stems as they strive to reach sunlight.
- Less nutrient and water absorption from the soil because of limited evaporation. This could result in overwatering problems.
Signs Your Calathea Plant Is Exposed To Too Much Light
The Calathea plant is affected by too low and too much light. You need a balanced medium light for it to grow and thrive without issues. Direct scorching rays from the sun are not friendly to Calatheas leaves.
Excess light could be the culprit if you see these signs on your plant.
- The plant leaves lose their charm and color, and the beautiful patterns fade.
- You see the tips of the leaves dry and turn crispy, although low humidity can also cause the problem.
- The leaves curl, turn brown, and die prematurely.
- Signs of sunburns on the leaf surface.
You might also enjoy reading: Why is Your Calathea Leaves Curling And Turning Brown (And how to fix it!)
But How Can You Revive a Calathea Plant Suffering From Excess Light?
The first obvious thing is to relocate the plant to a place without direct light access. If you place it near a window with natural sunlight, use curtains or blinds to filter the rays.
You may also prune the affected leaves so that your Calathea can start producing new healthy leaves. However, it would help if you take care when pruning, so you do not harm the plant. Photosynthesis must continue, giving the plant energy to grow, so avoid damaging the healthy leaves.
Relocating the plant to a good area in the house and providing it with the other conditions will revive it faster.
Tips To Improve Lighting Condition For Your Calathea Plant
If your house lacks good lighting, you are not doomed but can still plant Calathea plant. What can you do to enhance lighting conditions? Consider these practical steps.
1- Use Mirrors To Provide Indirect Sunlight.
If your ideal window gets excess sunlight, it may damage your delicate Calathea plant. Some use protection barriers to filter the light; however, if you do not have the barriers, you could try an alternative solution- the mirrors.
You could place the Calatheas in a dark or dim location and use a mirror to reflect sun rays from the window to the plant. The reflected light is indirect light, ideal for the Calathea plant. Mirrors will reflect the right amount and intensity of light that will not scorch the leaves.
2- Rotate Your Calathea Plant To Face The Light Source
If you notice that one side of your Calathea plant is not growing as the other side facing the window, you can regularly rotate it so that all parts receive adequate light. This problem often occurs when the plant is not correctly stationed, where one side is getting enough light while the other is deprived.
Rotating the plant allows the malnourished side to access light, enhance photosynthesis, and correctly grow. Additionally, you may need to change your watering schedule to promote balanced growth.
- During the growing season, around April to August, ensure you water your Calathea plant regularly to keep the soil moist (but not wet) and use a balanced fertilizer every month.
- Decrease your watering frequency and fertilization in winter when Calathea plant growth generally slows down, according to North Carolina State University.
Calathea plant requires attention and proper care to keep them strong and healthy. Getting indirect light for the plant is one way you ensure it thrives and produce happy and colorful leaves to enhance your interior and exterior décor.
Besides providing proper lighting, you also want to ensure the plants are well watered, the house humidity is ideal, and the temperature is balanced.
In the winter, when the sun rarely comes out, you can put your Calathea under grow light to keep them healthy. However, reduce the artificial lighting duration by an hour or two to prevent them from fading.
Sometimes you may need to rotate your plant so that all of its parts may have adequate access to light. However, ensure you do it gradually not to shock your plant.