Prayer Plants (Maranta leuconeura) get their name from how their boldly-patterned leaves move and “pray” by lifting and folding up after dark. Although they are beautiful, Prayer Plants can also be tricky for beginners to keep happy. They require consistent water and humidity and a location that provides them with “just right” light and temperature. They can be considered the Goldilocks of houseplants.
What light works best for Prayer Plants? Prayer Plants should be provided with low to bright indirect light, while (mostly) being kept out of direct sun that can damage their leaves. Although they tolerate lower light levels than many other tropical plants, Prayer Plants cannot survive in truly dark conditions.
Like all plants, Prayer Plants require a certain amount of light to photosynthesize water and carbon dioxide into glucose, which fuels their growth. Without sufficient light, they start to look scraggly and will not survive for long. If you have a Maranta that is failing to thrive, double-check light levels to be sure the plant has access to sufficient energy via sunlight.
Basics of Light for Indoor Plants
Lighting conditions inside a typical home are quite different from what a Prayer Plant would get in its natural habitat and from the lighting it would have received when growing in a nursery. To understand how we can evaluate light for a Maranta or any indoor plant, it’s important to have a good grasp of the basics.
All plants need sunlight (or a substitute). Since plants use light to create their own nourishment, a plant kept in the dark will basically starve to death. That said, a few species can survive only with artificial light, such as the fluorescent lighting in a windowless office. A Prayer Plant would not do well in those circumstances, but you could probably grow a Snake Plant or Pothos with only artificial lighting. Grow lights are a better source of supplemental lighting in darker spots because they give off the light spectrum that plants can use to photosynthesize.
We can’t trust our eyes. Our eyes continuously adapt to regulate the amount of light we perceive, meaning that it can be difficult for us to accurately determine the amount of light in a given situation. Just think of how dark your house seems right after coming inside on a sunny day, or how the objects in a dark room slowly become visible as your eyes adjust. This adaptation is very useful for allowing us to see efficiently in various circumstances, but it doesn’t help when it comes to evaluating how much light is actually available to our plants.
Care guides are not helpful. Lighting recommendations provided in plant care guides usually specify low, medium, bright, etc. Since these terms are both vague and subjective, trying to interpret them further complicates the process of figuring out how much light your plant needs. Luckily, it is possible to get down to specifics and use technology to find what suits different types of plants.
Light intensity can be measured in different ways. In general, indoor light levels are measured in lux or foot-candles. Lux and foot-candles measure the amount of light that falls on a surface, not the amount of light emitted from a source (lumens) or the amount of energy needed to generate that light (watts). Most people (with the exception of photographers and plant owners) never need to consider measuring light levels, so the process can seem confusing at first. But don’t worry – you’ll get the hang of it soon.
Foot-candles are the favored unit of measurement when discussing indoor plant lighting, so that’s what I’ll use going forward in this article. If you need to convert to lux, there’s a simple formula:
1 foot-candle = 10.76 lux
A foot-candle measures the brightness of the light hitting a surface, and as you might imagine, it was initially named for the amount of light cast a foot away from a certain kind of “standard” candle. Of course, we no longer use candles for lighting, but this anachronistic unit of measurement is still in regular use today.
PAR (photosynthetically active radiation) measurements are the most precise way to capture the range of light that can actually be used by plants. Unlike lux and foot-candles, PAR measures not just the quantity but also the quality of the available light. That is, how much of the light is able to be used by the plant for photosynthesis.
The technology behind measuring PAR also comes with a significant price tag, and for most houseplant owners, a measurement in lux or foot-candles is sufficient for their needs. If you get into growing rare, demanding plants or commercial growing, you may want to invest in a PAR meter. In the next section, I’ll recommend a budget-friendly light meter that works well for most plant owners.
How to Measure Light Levels in Your Home
Purchasing a light meter is a great idea, even if you’re an experienced plant owner. As mentioned above, our eyes (and brains) can’t adequately judge how much sunlight is coming in through our windows. You can be far more precise when choosing where to put a newly acquired plant if you know its specific light needs and what spaces you have that match those needs.
As with so many products, you can invest in a high-end, professional light meter or go for the cheapest, bare-bones model. This Dr. Meter Digital Illuminance/Light Meter is a great middle-ground – an inexpensive model that is easy to use and gives back accurate, consistent results. It can display results in lux or foot-candles, and I especially like that the sensor is attached by a flexible cord that allows you to get readings in hard-to-reach areas.
Use a light meter by placing the sensor in the position your plant is in – don’t point it at your plant or directly at the light source. If your plant sits on a windowsill or shelf, move the plant and put the sensor in that exact spot. You’ll see the display on the screen of how many foot-candles are available. Be sure to check it at different times throughout the day to get a complete picture of the amount of light your plant gets.
What about light meter apps? There are some light meter apps available, and they are cheaper than buying a separate device. Plus, you can reduce the clutter in your home by having one less object sitting around.
Unfortunately, light meter apps don’t work as well as freestanding light meters like the one mentioned above. The apps use the sensors in your phone’s camera to give an approximate light reading, but of course, a smartphone is not intended to be used for this purpose. Some light meter apps deviate 30% or more from the readings provided by a professional-quality light meter, so you should not trust an app completely.
That said, since most of them are free, you have nothing to lose by downloading and trying out light meter apps. Just be sure you don’t rely on these as the sole source of information when making decisions about your plants.
How Much Light Do Prayer Plants Need?
Prayer Plants like light that is bright, but they don’t want to be in direct sun for long. If you think about the kind of sunlight they would get on the tropical forest floor, you can get a sense of what their native environment would have provided – a lot of light throughout the day, but dappled and shaded by the canopy of trees above.
The minimum light level for a Maranta leuconeura to survive is around 100 foot-candles, but an area that measures around 200-250 foot-candles for most of the day will allow the plant to grow and thrive. They can even take a few hours of direct sun without being damaged, but be sure to introduce this gradually, so the plant has a chance to adapt to the increased light levels.
Direct vs. Indirect Light – What’s the Difference?
Direct sunlight is when the sun is shining directly on your plant with no obstacles in between. Note that you will sometimes see plants that grow outdoors labeled with “full sun,” which means they get direct light outdoors all day. Compare this with the direct sun available in a windowsill – even if light falls directly on the plant’s leaves, there is still protection from the roof and walls.
In most homes, a south-facing window would be the most likely location to receive direct sunlight for the majority of daylight hours. East- and west-facing windows get direct sunlight in the morning and evening respectively.
Indirect sunlight is reflected off other objects. If it is a bright day outside, but sunlight is not directly streaming in through your window, the light that enters your room is reflected off everything outside the window, such as the ground, other buildings, clouds, and the sky itself. Indirect light can be perceived as very bright by our eyes, so measuring it with a light meter can be surprising.
Another method to determine whether light is direct or indirect is by looking at shadows – if you see a defined shadow with clear edges, that’s direct light. Fuzzy shadows (or none at all) are cast by indirect light.
Can Prayer Plants Live in Low Light?
Maranta leuconeura and its relatives (Calathea, Stromanthe, Ctenanthe) are often sold as low light plants, but what does that really mean? They don’t need the same amount of light as many other tropical plants, but can they live in a dark room?
Prayer Plants need 100-250 foot-candles to survive. This puts them into the category of low-light plants, which also includes favorites like the ZZ plant and Sansevieria (Snake Plants). There are very few plants that can survive at less than 50 foot-candles, so a truly shady spot that’s far from windows is not a good choice for plants.
Marantas and their relatives need low to bright filtered/indirect light, but make sure they’re getting the required foot-candles. While Prayer Plants might survive for a while with lower-than-ideal light levels, they soon start to show the symptoms of insufficient light.
Effects of Too Little Sun on a Prayer Plant
A Prayer Plant that is receiving insufficient light usually demonstrates at least a couple of these symptoms:
- Legginess – stems are stretched and sparse, growing toward the light source
- Loss of lower leaves
- Pale leaves
- Stops moving and “praying” at night
- Susceptibility to pests and disease
The only way to revive a Prayer Plant that isn’t getting enough light is to move it to a sunnier location or to supplement with artificial lighting (more on that below). Sufficient lighting is one of the basic needs to keep a plant alive and looking great.
Effects of Too Much Sun on a Prayer Plant
In most homes, too little sun is more likely than too much, but Prayer Plants are susceptible to burning if they are allowed to sit in direct sun. Effects of too much sun include:
- Sunburn – brown or bleached spots, especially on those leaves closest to the window
- Leaves with dry/crispy edges
- Wilted/drooping leaves
- Curled leaves
- Overall dull and pale leaf color
If you suspect your Prayer Plant is getting too much sunlight, but you don’t have another suitable location for it, you can protect the plant from the most intense sunlight by adding a sheer curtain over the window. Moving it just a couple of feet deeper into the room can also do the trick.
Best Windows for Prayer Plants
In the northern hemisphere, south-facing windows are brightest, followed by west, east, and finally north-facing windows getting the least amount of sunlight. In general, a north- or east-facing windowsill usually works perfectly for Prayer Plants. Remember that Prayer Plants don’t like drafty locations, though, so if your windows let in cold winds from the north, you may prefer to choose a different spot.
Remember that obstructions can make a difference to your light levels as well. Buildings, trees, and window treatments will all decrease the amount of light that can reach your indoor plants. Also, the intensity of light decreases dramatically if a plant is just a short distance away from the window.
Likewise, a plant up on a high shelf doesn’t get as much as one on a windowsill because the ceiling partially blocks the sunlight throughout the day. Small windows let in less light than large windows, and dark walls or furnishings absorb the light, while light-colored walls and mirrors can reflect some of it to be used by plants.
Supplementing With Grow Lights
Although Prayer Plants can take shadier conditions, sometimes you want to put this plant in a place where there just isn’t enough natural light available year-round. Grow lights now come in a range of styles and colors, so you don’t have to put up with the classic pink lighting that most people associate with them.
Using the Sansi 15W daylight bulb, I was able to supplement sunlight for my Prayer Plants that sit on an interior shelf, about 10 feet from the nearest window. This bulb fits normal lamps and fixtures and gives off a pleasant light that truly does look similar to sunlight. It doesn’t get hot, so I don’t have to worry about my plants getting overheated. Also, since it’s an LED bulb, it uses very little energy and should last for years.
To replicate the circadian rhythm of the sun, you can pair a programmable timer with your grow light to provide 15-16 hours of light per day. Automating this process saves time for you and provides consistency to your Prayer Plants.
You can find details about grow lights along with some other recommendations by reading through this article: The Best Grow Lights For Your Houseplants.
Figuring out what kind of lighting is best for your Prayer Plant can be a challenge since descriptions of light requirements for plants tend to be unclear or vary between sources. It is also important to realize that our perceptions of how bright or dark a space is will be much different from how much light is actually available to be used by our plants.
Since Prayer Plants need sufficient light to grow and thrive, it is much better to use a light meter or even a light meter app to establish the intensity of sunlight in various areas of your home. Although Marantas are considered low-light tolerant, as compared with other plants, many people don’t realize how bright a low-light area actually needs to be.
Correct lighting conditions and consistent watering are the two most important keys to keeping your Prayer Plant alive and looking beautiful. If you can get these two elements right, you’ll be well on your way to successfully growing one of the more challenging houseplants around!