Understanding Your Plant’s Light Needs
Light is essential for plant growth, but the amount your plant needs depends on its type. Let’s explore different light conditions and find the perfect spot for your green friend.
Quick facts:
- Having enough light is essential for good plant growth.
- Choose a plant whose needs correspond to the amount of light in your house or place of business.
- Lack of natural sunshine can be compensated for by additional lighting.
- To meet your needs and budget, a wide variety of fake lights are available in various sizes and styles.
Why do plants need light?
Food and water are essential for all living beings. Food is light for plants. They use it in a crucial process called photosynthesis, in which light energy is absorbed by chloroplasts and sets off a series of biochemical events, one of which is the production of carbohydrates, or food, for plants. Since sugars are the energy source for plant growth, a plant will produce more energy and grow more quickly in response to increased light exposure.
Recognize these pairs:
Quality = Color
Quantity = Intensity
Knowing these aspects of light is crucial to understanding how and why a plant will respond in your house.
Quality
Color and type of light determine quality. Light is energy that has several wavelengths, each of which corresponds to a certain color. Because plants “see” light differently than humans do, colors that are visible to the human eye may not be beneficial to them. Green light is worthless to plants because they reflect it, which is why they appear green. Rather, plants require invisible light such as ultraviolet radiation from the sun and some infrared, as well as light that they can absorb and use, such as yellow, orange, red, blue, and violet.
Quantity
The amount of light that reaches the leaves is determined by its brightness or intensity. The leaf will develop more quickly and absorb more energy if it is exposed to more light photons. For example, begonias and oxalis require bright light to support their rapid development. A strong light source is also necessary for any plant to bear fruit or blossoms. These plants use simple elements like water, carbon dioxide, carbohydrates, and nutrients that are chemically assembled into complex molecules, such as floral colors, but only under the correct lighting circumstances. Certain plants possess self-regulating systems that prevent them from flowering or from trying to flower but failing midway through when exposed to insufficiently strong light.
Even in the most obscure shade outside, light comes in stronger from the brightest window inside.
Inside and outside
Outside, even in the shade, light bounces off surfaces from every direction, including the 180-degree arc in the sky above and 360 degrees around. When a plant is indoors, it receives its light mostly from one source, such as a sunny window, which greatly reduces the number of angles it receives light from and the quantity of light and essential photons it needs. Bringing a plant indoors essentially triggers an exponential decrease in photon exposure. This reality is a little easier to recall thanks to the beautiful quote above.
How excessive or insufficient light affects plants.
- Plants that receive insufficient light are unable to synthesize chlorophyll, which is the green pigment found in plants, and may instead turn pale green, yellow, or white.
- Plant stems can become “leggy,” which means they get long and thin and seem to be seeking for light.
- The plant develops big gaps between the leaf nodes—the points where leaves emerge from stems—on stems when there is insufficient light.
- Insufficient light can also cause plants to lose their leaves, especially the older ones.
- A variegated plant (leaves that are green and white) could turn back to being uniform green.
- Flower buds may not form on flowering plants.
- Excessive light exposure can cause burned and browned leaves on plants.
Footcandles and Indoor Plants
| Light Intensity | Footcandles | Light Exposure | Indoor Plant Examples |
| Low light | 25-100 FC | North facing windows or artificially lit rooms | ZZ plant, Snake plant, Cast iron plant, Peace lily, Resurrection plant (Selaginella) |
| Medium-bright light | 100-500 FC | East or west-facing windows | Chinese evergreen, Rubber plant, Dracena, African violet, Norfolk Island pine |
| High light | 500-1000 FC | South-facing windows or some west-facing windows | Croton, Hibiscus, Jade plant, Hoya |
| Direct indoor sunlight | Over 1000 FC | 4-6 hours of direct sunlight (sunroom or unshaded south-facing bay window) | Citrus, Succulents and Cacti, Gardenia, Tillandsia |
Types of Lights for Plants
Plants can be categorized based on their light requirements:
Find out how much and what kind of natural light your space gets before you buy a plant or start seeds. Then pick plants that can grow in the amount of light that your home provides.
A plant might be able to grow in less light, but it might need more light to make its leaves thick and flowers grow.
Low light
- For a north window or a pretty dark spot, a plant that doesn’t need much light would do well.
- Low-light plants don’t need much or any direct light. In the places where they come from, these plants are “understory plants,” which means they grow under the branches of bigger plants.
- Starting seeds indoors with low light is not enough.
- Plants grow more slowly and use less water when they are in places with less light. Feel the earth to make sure you don’t overwater it.
Medium light
- A plant that needs medium light would do well near a west-facing window that is not in full sunlight or near an east-facing window that faces east.
- For middle light, you would need to use artificial light to get seeds started.
- These plants won’t die out as quickly as the low light plants. Feel the earth to make sure you don’t overwater it.
High light
- A high-light plant would do well in places with a lot of light, like windows that face south or southwest.
- You might be able to start seeds without lights, but tomato and pepper seeds, which need more time indoors, might get too tall without extra light.
- Warm spots with a lot of light can dry out plants faster. More often, check on these plants and water them when the soil is dry.
Can I Add Artificial Lighting?
Of course, artificial lighting can be added to make up for the lack of sunshine. If you want to grow certain plants and know how much light your place gives off, you may decide to add extra lighting. Light bulbs that are most popular are LED and fluorescent, but you may also see incandescent and high-pressure sodium bulbs. Each type has pros and cons, and you can find them all online or at hardware shops near you.
Getting to Know Your Light and Space
What kind of light do you have? A quick test with your hands is a quick way to tell. Place your hand on a flat surface, like paper, about a foot away from the light source. It’s not bright enough if you can hardly see a shade. If there is middle light, the shadow of your hand will be fuzzy or blurry. If there is bright light, the shadow will be sharp and clear.
It will also help you figure out what kind of light you have if you know which way your windows face:
Windows that face north
In the Northern Hemisphere, windows that face true north never get full sunlight. The light that hits them is always soft and hazy. This group of plants, which includes the Dracaena Lisa, the Braided Money Tree, and the Snake Plant, does well when it is at least four feet away from a window that faces north.
Windows that face south
The windows that face south are the best in any room because they let in the most light during the day. The sun comes up in the east, and from late morning to mid-afternoon, windows facing south are lit by its rays because the earth is turning. Windows that face south get a lot of bright light throughout the day. Because of this, most plants will do well close to these windows, but bright light plants like the Bird of Paradise, Fishtail Palm, and Desert Cactus will do especially well.
On the subject of direct sunshine, windows that face south and are not blocked will get a good amount of it. However, most plants don’t like being in the harsh direct sunlight. When putting some plants right in front of a window that gets a lot of direct sunlight, be careful.
Live in a place with lots of sun? Find out more about the 10 sunniest cities in the U.S. that you should move to in our article. We talk about which plants to buy for places that are sunny all year.
Windows that face east
Since the sun rises in the east, windows that face east get light in the morning. Since morning light is usually soft, windows that face east are a good choice for plants that like bright light that comes from the side. A window that faces east lets you see the sun rise. Plants that do well in bright, indirect sunlight, like the Monstera Deliciosa and Fiddle Leaf Fig, do well next to windows that face east.
Take a moment to think about direct sunshine. Morning sunlight is usually soft, and most plants can handle direct sunlight from east-facing windows. If you live somewhere that gets a lot of sun, though (lucky you!), keep an eye on things in the summer. Plants that like to get some sun during the other months may not be able to handle it.
Windows that face west
By noon, the sun is high in the sky and about to start its slow fall as it goes down in the west. From mid-afternoon until evening, windows facing west will let in some sunlight. A west-facing window lets you see the sun go down in the afternoon. Windows that face west get very strong straight sunlight, so most plants should be put somewhere else where the sunlight doesn’t hit them. Some plants, like the Desert Cactus and succulents, can handle direct sunlight from a west-facing window. Others, like the Braided Money Tree or Tiger Evergreen, will do better with partial sunlight from this direction.
Plants Match (for light)
You’ve found your match (for light). Choose from this list of our all-time favorite plants for any amount of light you need. You may see that some plants are on more than one list. This is not a mistake! Some plants are lucky enough to do well in different amounts of dim light. Some of these stars are Snake Plants and Braided Money Trees.
Best Plants for Direct Light
- Bird of Paradise
- Fishtail Palm
- Desert Cactus
Best plants for bright indirect Light
- Fiddle Leaf Fig
- Dragon Tree
- Fishtail Palm
- Bird of Paradise
- Dracaena Compacta
- Rubber Tree
- Monstera Deliciosa
- Braided Money Tree
- Snake Plant
Best Plants for Medium Light
- Dracaena Lisa
- Dragon Tree
- Braided Money Tree
- Snake Plant
- Tiger Evergreen
- Silver Evergreen
Best Plants For Low Light
- Lady Palm
- Dracaena Lisa
- Cast Iron Plant
- Zanzibar Gem
- Silver Evergreen
- Snake Plant
- Parlor Palm
Also, remember that plants can be “conditioned” to different light levels. Just make sure you do this slowly over a few weeks. Your plant will go through shock if the amount of light changes quickly.
How to Tell If You Haven’t Found The Right Place Yet
If you see leaves that are turning yellow or falling off, or roots that are getting longer and thinner, it could mean that the plant needs more light. Your plant might need to be moved to a different room, a different spot in the room, or a lamp placed close.
Seeing pale leaves or spots that are getting crispy brown? This could mean that your plant needs more space from direct or too much light.
When To Move Plants Outside:
During the winter, when your plants need to be inside, our indoor plant light guide is very helpful. But when it gets warmer, moving your indoor plants outside can give them natural sunshine and rain, which is good for them.
Here are the safest ways to move your plants outside:
- Take it easy at first. Your plants are used to much weaker light inside, and even plants that get a lot of light can be shocked by bright sunlight outside. Move your plans outside slowly. Start by putting them in a shady spot under a tree for a few hours. Then, add more time and sunlight until your plants are happy.
- Make sure you check the temperature twice. Most houseplants come from places that are much warmer than your garden. You’ll need to check the temperature every day to make sure it doesn’t drop below 55℉ if you want to move your plants outside when it gets warmer. In many places, you’ll need to bring your plants inside every night to keep them from freezing.
- Pay attention to the weather. Some light rain is good for houseplants, but a rapid downpour can easily shock them. Make sure your plants are in pots that drain well so they don’t drown in the rain, and bring them inside if it’s going to rain a lot. You should put your plants somewhere safe, like near the side of your house, because wind can also blow them around or knock them over. If high winds are predicted, bring your plants inside.
- Keep an eye out for bugs. Bugs are everywhere outside, not just inside your home, where you can control them. Check your plants quickly for bugs and get rid of them before you bring them back inside. You can also keep your indoor/outdoor plants separate from the rest of your collection to stop the spread of diseases and pests. If you find bugs on your flowers, like aphids or spider mites, our experts have written a guide on how to get rid of them. You can use it when you bring them back inside.
What Plants From The Inside Can Go Outside?
Still not sure if you should bring your plants outside? Sort your plants by how hardy they are first. Taking plants outside is best when they don’t have strict needs about how much light they get or water they get. Here are some examples of these plants:
- Rubber Tree
- ZZ Plant
- Snake Plant
- Pothos
Never hesitate to see a knowledgeable staff member at your neighborhood garden center if you’re still unsure about how much light your indoor or outdoor plants require! Practice makes perfect, so experiment with different arrangements for your houseplants until you achieve the ideal results.
By understanding your plant’s light needs and following these simple guidelines, you can create a thriving indoor garden.