Place your indoor plant in front of a window. Water it regularly. Watch it flourish. Sounds simple, right?
It’s not. Finding and maintaining healthy lighting dynamics for indoor plants is far more complex than many believe. And with inadequate lighting or plant sunburn mimicking dozens of other health issues, inappropriate lighting is a silent but deadly killer in houseplants. Use our guide to find the best natural light sources and positioning for your leafy roommates!
Choose the correct placement for your indoor houseplants, and their specific preferences.
The sun rises in the east and sets in the west.
East or West Facing Window: Part Sun, Part Shade!
East-facing windows receive the first rays of bright sunlight in the morning. Their direct sunlight will wane at noon, when the sun is perfectly overhead. Naturally, west-facing windows are the opposite, receiving direct sunlight during the late afternoon.
Both window placements avoid the intense and unbearable heat of the midday sun. An important differentiation is that west-facing window placements receive light during the warmest part of the day, which may cause some plants to burn. High-light plants, however, thrive in this placement, and medium-light plants can also prosper with decent cover, or a bit of additional distance from these windows.
Many plants, such as flowering plants, bloom close to an east or west-facing window, in part sun and part shade. Many others can adapt quite nicely to these conditions.
South Facing Window: Full Sun!
South-facing windows receive the most direct sunlight during the late morning and early afternoon. While the sun rays are strongest during these hours, direct sunlight will continue throughout the day. High-light houseplants are usually best for these windows.
Similarly, to east and west-facing windows, medium-light plants can also grow well near south-facing windows, with appropriate protection. Additional distance, plant cloth, curtains or shielding provided from other plants can help protect medium-light plants.
It’s worth noting that if you have other window options available, those might be best, as most houseplants will not prefer this placement, minus some cacti and succulent varieties.
North Facing Window: Full Shade or Low Light!
Most plants do not grow at their best in shaded or low-light conditions, including flowering types. However, many houseplant species survive and thrive in low lighting conditions, including “easy” and “beginner” plants such as the dragon tree, ZZ plant, pothos and snake plant.
A north-facing window provides full shade, but low light can often depend on the size or amount of windows in a room. Another nearby window facing another direction will boost the room’s light level. This lighting can also be supplemented by additional artificial lighting, like grow lights.
South, East or West Facing Window: Bright Light Without Direct Sun!
Windows facing either south, east or west are suitable for “bright light without direct sun” preferring plants, with additional precautions.
The best source for this lighting preference is a south-facing window, with the plant set back a few feet from the window. East and west-facing windows are also suitable, if the window is large enough to allow in plenty of daylight, with the plant sitting far enough back from the harsher morning or evening direct rays.
Now that you’ve selected your window, pay attention to these additional factors.
Firstly, note the distance between your plant and the window. Under perfect conditions, plants pushed right up against a window might receive 100% of the light that’s coming through the window. Intuitively, placing the plant further away from the window reduces the light it receives. The deeper into the room the plant is placed in, the less light it receives. Even a meter or so removed from the window can reduce the amount of lighting by 25%.
The condition of your window glass also matters, dramatically. Believe it or not, plants prefer clean, shining windows! Dirty, smudged windows act like a filter, reducing the amount of light that comes through by up to 10%.
Furthermore, the objects outside of your window altar the amount of light your plant is actually receiving. Trees, large shrubs, patio coverings, or any other kind of light disruption may reduce the amount of light your houseplants can receive by a tremendous amount.
Likewise, the surroundings of your plant from within your home also drastically shift its light dynamic. While objects outside your window may diminish light, objects around your plant can increase it. Reflective surfaces, such as properly positioned mirrors and large, white objects, will bounce and reflect light around your plant. When used strategically, this is a great way to maximize the amount of light in a room, particularly if it’s low light to start with.
Intuitively, curtains or blinds placed in front of plants will reduce lighting, as will shielding provided by other objects or plants. This can harm high-light requiring plants, or it could be used advantageously to protect lower-light plants.
South-facing windows, for example, may become darker and cooler due to your room setup, opening up the location to a wider variety of houseplants. Heavily shielding an east-facing window, on the other hand, may render it unsuitable for high-light requiring plants.
Are your plants suffering from inadequate lighting in a too-dark room?
Insufficient lighting can wreak havoc in houseplants and kill them rather quickly. Multitudes of health problems may arise in poorly lit plants, including root rot (from water not being used to photosynthesize), pests and more.
Generally, most plant leaves have a dark green appearance. This rule, of course, has plenty of exceptions, including variegated plants, neon Pothos and so on. Nevertheless, this green color is created by chlorophyll within the plant’s cells. Chlorophyll soaks up incoming light in order to photosynthesize. However, insufficient light exposure halts chlorophyll from peak performance. Leaves slowly lose their dark coloring, becoming light over time.
If lighting conditions do not improve, the leaves will eventually yellow and fall off of the plant. Additionally, plants which aren’t photosynthesizing will consume less water, rendering even “regular” watering as overwatering.
Before diagnosing your plant, note that inadequate lighting symptoms also mimic other problems, such as too much sunlight, ironically. We always encourage plant enthusiasts to gauge room lighting with a light meter to ensure their plant is positioned well, and that the positioning meets the specific plant’s lighting requirements.
Symptoms of Inadequate Light:
- No blooming in flowering plants
- Weak, slow and spindly growth, and growth leaning toward natural light or grow lighting fixtures (phototropism)
- Yellowing leaves which eventually fall
- New leaf growth smaller than usual
- Longer than normal internodes
Photosynthesis uses primarily blue and red rays from the light spectrum for energy production. Plants receiving insufficient lighting may “lean” toward a natural light supply in a process called phototropism. Rotating your plant regularly can prevent unsightly, uneven growth. If rotating the plant regularly isn’t possible, orient the plant so that all of its stems and leaves can reach the rays of sunlight, or supplement its lighting with grow lights.
Plants, particularly hearty varieties, will fight hard to stay alive. Insufficient lighting may still offer a bit of energy to the plant so that it can grow its stems slowly. However, you will notice that these stem growths will have more spacing between leaves. These spaces are called “internodes.” Long internodes are a symptom of a lack of light, as are thin and unusually small leaves.
In order to restore underlit plants back to optimal health, carefully and safely increase their lighting dynamic. Strategic window placement is an excellent method. Supplementary grow lights and well-placed reflective objects, such as mirrors, also improve lighting conditions. This guide thoroughly explains these tactics.
Or are your plants burning from too much light (leaf burn, sun stress, sunburn or scorch)?
Many plants thrive in the sunlight. Known as high-light plants, these green beauties require about 6 hours of full sun every day. Others, dubbed low-light plants, prefer their shade. In their natural habitats, these plants grew in the shadows of large trees, in forest floors, and in darker planetary terrains. In their native lands, the natural light that reaches these plants is immensely filtered by the canopies above.
When you grow plants indoors, they may receive more light than they can photosynthesize. Shade-loving plants are particularly vulnerable to this, but even high-light plants can fall victim to leaf burn, leaf scorch or plant sunburn. This disease notably causes plants to lose their vibrant, natural color and become bleached.
Scientifically, plant sunburn occurs because plants recover energy from the sun with the help of two photon-capturing molecules, chlorophyll and carotenoid. If plants are exposed to too much sun, these molecules absorb more energy than they can handle, and create toxic free radicals that can quickly kill the plant.
In summer months, many plant enthusiasts opt to move their plants outside permanently for extra sun and rain. Yet plants which have been sheltered in indoor environments are particularly vulnerable to sun damage. Read the next section to learn more about when and how to transition your plant to an outdoor location.
Symptoms of Too Much Light:
- Flowers shrivel up and quickly die
- Leaves wilt, droop and shrivel up or turn in at corners, ultimately drying out and dropping from the plant
- Leaf margins turn brown along the entirety of the edges, rather than just brown tips
- Brown, dry spots on leaves and/or pale green, white or gray coloring, resembling “bleaching”
- Leaves lose pigmentation and leaf veins become discolored
- Stunted growth
This list contains general warning symptoms to watch out for. Depending on your specific plant, the symptoms of sun damage may vary a bit. Plants with wooden branches or trunks may display sunscald and other illnesses, so remember to inspect your whole plant, rather than solely the leaves.
An effective way to diagnose plant sun stress is to notice which parts of your plant are the most heavily affected, and their proximity to your lighting source. Affected areas will become dry and brittle and may develop holes over time. If the light is coming from above, the loss of color and change of texture of the leaf will occur on the upper side or top of the plant, with the underside remaining healthy.
Again, before diagnosing your plant, note that over lighting symptoms also mimic other problems, such as too little sunlight, ironically. We always encourage plant enthusiasts to gauge room lighting with a light meter to ensure their plant is positioned well, and that the positioning meets the specific plant’s lighting requirements.
While sun damage won’t kill your plant immediately, within a few days or weeks, it can cause tremendous lasting damage or become lethal.
Plant sunburn is treatable if caught quickly. Firstly, as aforementioned, determine the light tolerance of your houseplant. This ranges from low to medium to high tolerance. Many factors may impact a plant’s light tolerance, including light intensity, quality and duration, which are discussed in detail in this guide.
Briefly, light intensity, light quality and duration all affect a plant’s light tolerance. Intensity is set by the natural lighting (or artificial, if supplemented with grow lights) sources your plant is exposed to. The cardinal direction of your windows, your plant’s proximity to the windows, and other objects inside and outside of your home all contribute to this dynamic.
Light quality can be altered by filtering light. If your plant is receiving too much sun, hanging thin curtains to block out some of the light can improve its lighting conditions.
Duration of sun exposure is equally important and should be decided based on your specific plant’s light requirements. The longer the leaves get sunlight, the more chlorophyll breaks down. Some plants require more hours of darkness than others in order to grow and/or flower.
As deadly as plant sunburn may be, if plant enthusiasts diagnose and treat the illness quickly, the plant may survive and regain full, lush foliage. An immediate and appropriate response will increase its chances of survival.
Once you’ve diagnosed your plant with sun stress, change its location to suitable conditions immediately. Different species of plant require different light dynamics. Thoroughly research your plant, and place it near a dimmer lighting source, or alter the conditions of its current source.
For instance, you may opt to move your plant from a brutal, full-sun south-facing window to a brightly lit, cooler west or east-facing window. Or perhaps you’ll keep your plant in a south-facing window and move it a few feet back and utilize sheer curtains to help shield the plant from heavy rays.
This guide discusses controlling lighting dynamics in depth, and as always, a light meter should be used to gauge the amount of light your new location contains.
Additionally, overly heated, sun-scorched plants are immensely prone to dehydration. Evaluate your plant’s hydration levels, and if thirsty, give it a nice soak. Covering leaves and stems with water, in addition to soil, will increase humidity levels around the plant, preventing further damage.
Next, prune your plant! Damaged leaves and stems will not recover, and they use up valuable plant resources. Using clean and sterilized gardening shears, trim all of the dried-up leaves, stems and flowers.
How and when should you transition your indoor houseplants to the outdoors?
Many houseplant owners decide to move their indoor plants outside during summer months for additional natural sunlight and rainfall. I’m looking at you, spring seedling-starters. However, immersing sheltered, indoor houseplants into the great outdoors all at once is not safe. They must carefully be transitioned into a drastically different environment. The following are our tips to safely move your indoor plants outside.
Firstly, start slowly. Indoor plants are accustomed to weaker light, and direct sunlight can be shocking even to high-light plants. Slowly acclimate your plants to the outdoors by placing them in shady spots for a few days, and gradually adding sunlight in increments until they’re adapted and thriving.
Also, check the temperature! Note your specific plant’s temperature preferences, ensuring that your plant doesn’t overheat, or in winter months, freeze. When it’s too hot or too cold, bring your plants back inside to wait out the extreme conditions.
Be mindful of the weather as well. Light rain is typically good for houseplants, but sudden heavy downpours and flooding conditions can shock them easily. Make sure they’re planted in well-draining pots (i.e. terracotta) to avoid overwatering illnesses like root rot. Wind can also shock plants by tossing them around or knocking them over, so ensure their location is well shielded, like near the side of your home, and bring them inside during unusually high winds.
Lastly, watch out for pests. Bugs are everywhere outdoors. If moving your plants back inside, carefully inspect them for signs of spider mites or other pests or diseases. Quarantine them from your indoor plants to avoid the spread of anything that you might not see, until you’re certain your plant is pest-free.
If you’re still nervous about where to begin, start by moving your hardiest plants outdoors. Plants that aren’t picky about light level or water consumption are the best options to safely move outside first, such as rubber tree, ZZ plant, snake plant and Pothos.
Good luck, and happy gardening!
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