Plants and Light
Light requirements for houseplants can seem complicated at first. (What, after all, does "low light" really mean?) But, when trying to understand a plant's light needs — and needs in general — a good place to start is by doing a little research about the conditions your plant would have in its native habitat.
Cacti and succulents originate in dry, sunny locations like deserts. As such, they are going to perform best when placed in a south-facing window that gets as much sun possible.
Generally, plants that are grown for flowers and fruit need access to high levels of sunlight that provides them with the energy they need to successfully produce fruit — imagine sunny gardens and farmer’s fields. Many of these plants will enjoy your south-facing windows as well.
Plants that are grown for their beautiful leaves often need less light. Many foliage plants come to us from rainforests where they grow under the canopy of large trees. Some of these plants may enjoy gentle morning sun, but they need to be protected from direct exposure to the sun's harsh afternoon rays.
Delicate tropical plants like orchids and ferns are acclimated to growing deeper in the rainforest under greater protection. Therefore, they appreciate indirect light. Many can thrive even in a north-facing window.
When selecting plants, it is always best to choose plants that fit your existing lighting situation, rather than trying to change your space to accommodate your plants. That isn't to say it can't be done, but when starting out, this is definitely the easiest way to ensure success and build confidence.
Fixing Issues with Light
If possible, the best and most obvious way to deal with a light issue is to move your plant to a better lighting situation. Sometimes this could just be a few feet away from its current location, such as closer to a window, or to a window that receives more sunlight throughout the day. If you are making a big change — even for the better — it is good to do so gradually in order to give your plant time to acclimate to these changes. While the change from low light to moderate light might be relatively easy, moving a plant directly from a dark corner of your home to the brightest window you have could stress your plant and cause its leaves to burn. Similarly, keep in mind that plants adapt to new situations slowly, and it may take a while to see evidence of any change's impact on your plant. Be patient!
The Interrelationship of Light and Water
Generally, the more light and heat a plant receives, the more water it needs, and vice-versa: The less light a plant gets, the less water it needs.
In some cases, certain plants can adapt to more light than they ideally would like if you increase the amount of water they receive. Be careful though, as this isn’t the right fix for everything! For some plants, more water will just cause them to rot, so make sure to do your research.
Troubleshooting Lighting: Too Much
If you notice that your plant has burned patches on its leaves, it might be getting too much light. Often the burned areas will be dry and a pale white-tan in color; other times, these patches may be brown with white interspersed. Plants getting too much light might also drop their leaves.
Possible Fixes
If moving the plant isn’t possible, there are some other ways to fix light issues. If you are having an issue with too much light, take a look at the chart above outlining the light received by windows in different exposures. For example, if you have a houseplant that wants bright indirect light and you have it in a west facing window, adding a sheer curtain will likely fix the issue. Sheers will let light through, but decrease its intensity just enough.
Dark pots, walls, or furniture with matte finishes will absorb excess light. Be careful with dark pots, though. In some cases, they may absorb too much heat for your plant's roots.
Troubleshooting Lighting: Too Little
On the other hand, if you are noticing yellow discoloration, stunted leaf growth, elongated stems, plants that look as though they are reaching toward the light source, and/or a dull color, your plant might be getting too little light. Plants getting too little light may also drop their leaves, which can be a tricky symptom to understand. (Sometimes yellowing and leaf-drop is also caused by overwatering. Make sure to read our blog post all about watering.)
Possible Fixes
If all the windows in your house face North and you dream of growing indoor plants that need bright light, you might want to look into installing plant lights. Full spectrum grow lights are the best, but even dedicated time close to household LED lights can help. Mirrors can be used to reflect light to areas that would otherwise be darker, and white pots, walls, furniture, and shiny finishes can increase the amount of light in a room.
Conclusion
Always remember that plant care is experimental! Don’t be afraid to try different things while you are figuring out what works best for you and your plants. Keep in mind that individual plants or different cultivars can have different needs depending on their biology or what conditions they were in prior to arriving in your home.
