Like any beauty queen, your Calathea will be happiest when it’s in the right lighting. As with every aspect of this irritable plant’s care, balance is critical – these plants are sensitive to sunburn, but won’t reach their full potential in a room that’s too dark to let them grow. This article will break down the lighting conditions that will enable your Calathea to thrive.
What light is best for Calatheas? Calatheas do best in sunlight that’s bright but indirect, meaning it’s filtered through other materials or reflected off other surfaces on its way to their leaves. An eastern exposure is ideal, while a spot a few feet back from a southern or western window should also work quite well.
Lighting can vary from region to region and throughout the year, so don’t just place your Calathea in one spot and forget about it. Instead, keep an eye on its growth and health, adjusting the lighting conditions if it seems to be receiving too much or too little sun. This article will explain some of the warning signs that can alert you to a lighting issue in your Calathea and offer some guidelines to help you find the right place for your plant.
How Much Light Does a Calathea Need?
In nature, Calatheas grow in the shade of tall rainforest trees, protected from the rays of the scorching sun. This leads many care guides to refer to them as “low-light plants.” However, while it’s true that your Calathea shouldn’t sit in full sun, it’s a bit misleading to conclude that it will be happy in low light.
In the tropics, even fairly shady outdoor spaces receive a lot of sun over the course of the day, especially compared to the inside of a typical North American home. That means Calatheas are actually accustomed to receiving a substantial amount of daylight. They simply prefer the kind of diffuse, dappled sun that’s typical of a forest floor.
Plant care experts refer to this type of illumination as bright, indirect light. For those not familiar with the distinction, indirect sunlight means that most of the photons reaching a plant have already bounced off some other surface, or been scattered by a partially translucent barrier such as a thin sheet of fabric. Direct sunlight means there’s little or nothing getting between the sun and the leaf.
One quick way to tell the difference: if you can read a book without turning on a lamp, you’re standing in a spot with bright light. If you can’t, the light is dim.
Now, look at the shadow you’re casting. Is it dark and clear, with sharply defined edges? If so, you’re getting direct light. The right lighting for Calatheas will produce a slightly fainter shadow, with more blurring around the margins.
Those who prefer precision (or just want an excuse to buy a new gadget) can pick up an illuminance meter to get a more definitive reading on the light intensity. The standard unit of measurement is the foot-candle, which is precisely what it sounds like: the amount of light cast by a candle standing one foot away. Bright indirect light falls within the 1,000-2,000 foot-candle range.
Finding the Right Location For Your Calathea
Whether you use an illuminance meter or the shadow test, you can’t rely on a single reading because the direction of the sun’s rays changes throughout the day. A spot that’s not receiving direct light now might be right in the glare of the sun in a few hours.
Thankfully, “keep your Calathea out of direct light” is a guideline rather than a life-or-death rule. You shouldn’t leave your Peacock Plant sitting on your patio at high noon, but it also doesn’t need to be locked away from the sun like a madwoman in a gothic romance. One to three hours of direct light a day will energize your Calathea rather than hurt it.
Timing affects the intensity of sunlight – both the season and the time of day. Your Calathea will be more vulnerable to sunburn in the spring and summer and more secure in the gentler light of evenings and early mornings.
Another factor worth considering is the type of Calathea you’re growing. Varieties with darker foliage, like the Velvet Leaf Calathea or the Pinstripe Plant, thrive in dimmer conditions; those with a lot of light green coloration, like the Rattlesnake Plant, can withstand a bit more light.
Finding the right lighting for your Calathea will require some experimentation, but we’ll provide some handy pointers to get you started.
Where is Your Calathea Getting its Light?
The first factor to consider in placing your Calathea is the direction of exposure – in other words, which way the windows face. If you live in the Northern Hemisphere, the sun spends most of the day in the southern skies. A room that’s open to the south will get more direct light than any other part of the house.
That means your Calathea will suffer if you place it right in a south-facing window, because it will have sun streaming down on it throughout the daylight hours. In a room with southern exposure, the plant should sit 4-6 feet back from the closest window. That will keep it out of the harsh southern rays but still allow it to soak up lots of reflected light.
Western windows only admit direct light for a few hours a day – but those hours fall in the mid-to-late afternoon, when ambient temperatures are highest. This combination of high heat and bright light can easily fry the sensitive leaves of a Calathea. Treat western windows much like southern ones, keeping your plant a few feet away from the sill.
Eastern windows are usually the sweet spot for Calatheas, letting them take in a few hours of direct sun in the coolest part of the day before shifting to indirect light as the air heats up.
A room with only northern exposure will eliminate the risk of sunburn but might not admit enough light to let your Calathea reach its full potential. You’ll have to evaluate on a case-by-case basis. Keep an eye on the plant’s growth rate to see if it appears to be starving for light.
Filtered Light For Calatheas
Looking for another way to keep your Calatheas energized but safe from sunburn? Make like an Instagram influencer and apply a filter. You can reduce the harshness of direct sunlight by setting up a barrier, such as a paper folding screen or a sheer curtain, which will scatter and soften the light passing through it. And as a bonus, you can use this as an opportunity to spruce up the room’s decor.
This method lets you take advantage of the bright light from a south-facing window without scorching your Calathea. Curtains made from a thin fabric like linen, lace, or chiffon should work; just pick a loose weave that won’t completely block the light. Venetian or vertical blinds left partially open can also work well for this purpose.
Watch the Heat
Direct sun damages Calatheas by dehydrating their foliage. When a plant receives more sun than it can handle, it releases extra water from its pores to compensate. Calatheas can’t sustain that increased rate of transpiration for long, and as the leaves run short of water, the cells crumple and die. This results in faded, withered spots of dead tissue. If it keeps up, it can kill the plant entirely.
Evaporation speeds up when it’s hotter, so higher temperatures render your Calathea more sensitive to sunlight. The risk of sunburn increases as temperatures climb above the 70s. And when it gets hotter than 90 degrees, your plant will be stressed even if it’s fully shielded from direct light.
Humidity and Sunburn in Calatheas
Sunburn and humidity issues go hand in hand – the more vapor in the air, the longer it will take the plant’s leaves to dry out and scorch. So make sure that your Calathea’s environment contains enough ambient moisture to keep the plant healthy.
Since it hails from the tropics, your Calathea will be happiest when humidity levels are above 60% (with the ideal range falling around 70-80%). You can monitor the humidity with a simple hygrometer. If you’re finding it hard to keep your home as humid as your Calatheas would like, there are a few tricks that can enhance the moisture levels around your plant.
If you have multiple humidity-loving plants, one simple strategy is to cluster them together. Plants in close proximity form a kind of mini-rainforest, each one benefiting from the water vapor that its neighbors release.
Another low-effort method is a humidity tray. Take a shallow dish with a flat base and pile it full of smooth pebbles, gravel, or beads. Then add some water – as much as you can without letting the water line reach the top of the stones.
Your Calathea’s pot will sit on top of the pebbles, keeping it above the standing water. That way, the soil won’t become soggy and cause root rot. As the water evaporates, it will give a slight boost to the humidity around your plant’s leaves. It’s only a minor enhancement, but sometimes that’s all you need.
Some indoor gardeners like to mist their Calatheas from a spray bottle. This is a more involved method, since you’ll have to spray the plant several times a day to achieve any noticeable improvement. There is a fringe benefit, though: like anything that gets you to check in with your plant frequently, misting will help you monitor your Calathea’s needs.
Last but certainly not least, you can set up a humidifier next to your Calathea. This is generally the most effective option, and it also doesn’t require much effort on your part. Many humidifier models can switch between warm and cool mist settings, helping you manage your plant’s temperature as well as keeping it moist.
Is My Calathea Getting Too Much Sunlight?
A Calathea that’s been damaged by the sun will start to turn yellow or pale brown, with dead patches of shriveled, crispy tissue appearing on its leaves. This can cause the ordinarily gorgeous patterns on your plant’s leaves to fade and become indistinct. Many growers informally refer to this problem as a sunburn, though it’s also called sun scorch or leaf scorch.
The edges of dehydrated leaves may also curl in toward the central vein. This is a mechanism the plant uses to protect itself by reducing the number of pores exposed to the air, thus limiting the amount of water lost through transpiration.
Low humidity or high temperatures can give rise to symptoms much like sun scorch, even in dim lighting. Other potential causes include overwatering, underwatering, and fertilizer burn – anything that prevents your plant from getting enough water to its leaves.
In those alternate scenarios, the discoloration may be concentrated at the tips and edges of the leaves, while sun scorch is more likely to be distributed in patches all across the leaf surface. If the crispy spots are concentrated on the side of your Calathea that’s closest to the window, that’s a dead giveaway that you’re dealing with leaf scorch.
Reviving a Sun-Scorched Calathea
When you suspect your plant has been damaged by sun exposure, move it to a spot with no direct sunlight at all for a few weeks. It should begin to recover as soon as it’s away from the danger zone, though any damage it’s already suffered will be permanent. You can prune away the brown and shriveled parts of the leaves (more on that here), but leave healthy tissue in place; it will continue to photosynthesize, providing the energy your Calathea needs to generate fresh foliage.
If the sun scorch is extensive enough that your Calathea loses multiple leaves, you should reduce any fertilizer that you’re providing. A reduction in foliage limits your plant’s growth rate and, therefore, its nutrient uptake. If you provide more fertilizer than your Calathea can use, you may damage the roots.
You’re likely to see improvement within a few weeks, though the recovery time will be longer if your Calathea has suffered extensive damage.
Is My Calathea Getting Too Little Sunlight?
The most common sign of an under-lit Calathea is that its growth slows down or stops. These plants are unlikely to die of dim lighting unless it’s extremely prolonged, but they won’t be in a hurry to expand, either.
You might also notice that the foliage takes on a deeper green color as the plant adds more chlorophyll, aiming to soak up as much light as it can. This shift may cause its leaf patterns to fade as the contrast between the darker and paler portions becomes less pronounced.
One other possible sign of insufficient light is a plant that has stopped “praying.” Calatheas are closely related to Maranta leuconeura, the Prayer Plant, and they follow the same daily routine, spreading their leaves out in the daytime and folding them up at night. But this motion is guided by the cycles of light and dark, so your plant may fall still when the daylight in its room isn’t bright enough.
Enhancing Light For Calatheas
Switching your Calathea to a brighter spot is the simplest fix for insufficient lighting. Try moving the plant from a north-facing to an east-facing room or placing it a bit closer to a window. If possible, make the transition in stages – Calatheas are known to react poorly to sudden changes. Start by giving the plant an extra hour or two of sun each morning, then gradually step up its exposure.
You can also try adding some store-bought illumination in the form of a full-spectrum grow light. We recommend LED lights because they’re energy-efficient and therefore unlikely to scorch your Calathea with excess heat. Our typical recommendation, the Sansi 15W LED bulb, can sit a foot or so away from the plant without harming it, though it’s best to experiment a bit to find the ideal range.
You’ll also need to feel out how much time your Calathea needs under the grow light. 6-7 hours a day should be fine if the plant only needs a small boost, while 12+ hours may be warranted if it’s in a really dim space. A lamp timer makes it easy to set your Calathea’s lighting schedule. Take a look at our article on grow lights for more detailed advice on choosing the right lamp for your plant.
Final Thoughts
Keeping your Calathea well-lit means finding the right balance of exposure, moisture, temperature, and timing. It may take some trial and error to find the perfect location for your Peacock Plant, but it should remain healthy as long as you give it time to adapt to every change and avoid giving it more than 3 or 4 hours of direct light. Be patient and cautious, and before long, you’ll find the lighting that brings out your Calathea’s star power.