Having indoor plants in your home is a great way to brighten it and introduce nature indoors. However, you might notice some of your sun-exposed indoor plants are looking sun-scorched. What causes this?
Indoor plants can get sunburned if they’re exposed to too much sunlight. Depending on their exposure rate, their upper leaves can turn yellow or white with brown edges. Sunburned leaves cannot recover, but you can save the plant by removing it from direct sunlight.
The rest of the article will explain how your indoor plants can get sunburned, ways to revive them, and the measures you can take to protect them.
Can Plants Get Sunburned?
As much as they need sunlight to make food through photosynthesis, plants can get sunburned if they get too much of it. But how does too much sunlight affect plant growth?
According to a 2014 article by the American Chemical Society, ultraviolet (UV) radiation, particularly UVB, can cause severe damage not only to the plant’s looks but also to its DNA structure.
This causes the plant to grow more slowly even after it has recovered from the initial sunburn effects.
However, the same article also discussed how plants make sunscreen called sinapate esters, which are special molecules plants coat their leaves with. This means that your plants can still tolerate direct sunlight, but only if it’s just enough to process their nutrients.
A 2017 study from Michigan State University also discovered that too much sunlight can cause a plant’s photosynthesis system to stop repairing itself. This is because heavy sun exposure can cause plants to lose their MPH2, the protein responsible for the repair.
Another reason indoor plants may get sunburned is low soil moisture and high environmental temperature. This is because soil moisture aids in cooling off your plants when it gets too hot.
How much sunlight is too much ultimately depends on the type of plants you have indoors. Succulents like cacti and agave love getting at least six hours of direct sunlight daily.
On the other hand, non-succulent indoor plants, such as bromeliads or ferns, prefer indirect sunlight and wouldn’t do well with direct sunlight, especially during the summer.
This video provides an excellent explanation of how indoor plants generally prefer their lights. It also details the different ways you can provide lighting for your plants:
How To Deal with Sunburned Plants
Unfortunately, there’s not much you can do to revive sunburned plants. Ultimately, the process is irreversible for the affected leaves or stems.
However, there are some measures you can take to help your sunburned plant recover:
Place Your Plant in the Shade
You should place your plant in a cool and shady spot as soon as you notice the telltale signs of sunburn, such as brown or white leaf edges, dried stems and stunted growth. The sooner you move your sun-scorched plant into the shade, the better its chances of survival.
Adjust How You Water Your Plant
While you might be tempted to give your plant more water than you usually do, this is one of the worst things you can do since sunburned plants are vulnerable to the effects of over-watering.
Sunburned plants typically lose most of their leaves, so they won’t need as much water as they did before. Moreover, their roots may also be affected, so watering them too much and too soon can lead to root rot or bacterial growth in waterlogged soil.
A good rule of thumb is to water them with half as much water than before.
Remove the Sunburned Leaves
Gently removing sun-scorched leaves helps prevent unnecessary energy loss from your plant because plants will typically consume more energy to repair damaged parts. Since sun damage is irreparable, it’s best if the plant grows new leaves to recover faster.
Removing the sunburned leaves is easy and involves gently pulling them off the plant.
Apply Fertilizer to Speed Up Recovery
Fertilizer is an excellent way to help your plant recover from sunburn. However, you should use less than you normally would. Like watering, a good rule to follow is to halve the amount you would normally use to prevent fertilizer burn.
Use Organic Fertilizer
Using organic instead of chemical fertilizer can also help revitalize a sunburned plant. This is because chemical fertilizer products tend to have higher acid content than the former, making affected roots more susceptible to damage.
Burpee Natural Purpose Granular Organic Food from Amazon.com does an excellent job of helping sunburned indoor plants. Its balanced NPK (Nitrogen, Phosphorus, Potassium) content works well for almost all your plant’s needs. It’s also made from organic materials which introduce beneficial microbes to your soil, extending your plant’s nutrient boost for up to three months.
Alternatively, use the sunburned leaves you cut to fertilize the parent plant. However, let them decompose in compost for better nutrient absorption and less moisture content.
How Can You Prevent Your Plants from Getting Sunburned?
Now that you know how plants get sunburned and how to revive them, let’s discuss how to prevent this from happening again:
Move Them Away from Sunlight
The best way to prevent your plants from getting sunburned is to prevent excessive exposure to direct sunlight.
Most indoor plants prefer bright light from east or west-facing windows since these give off the most balanced range of sunlight.
In contrast, south-facing windows give the brightest light conditions for more hours, so they’re recommended for succulents. However, they are not suitable for sun-sensitive plants.
Conversely, north-facing windows are the best locations for plants that need less light.
Still, these are general rules that you should take with a grain of salt. To protect your plants better, you should take note of your plant species and keep track of their preferred lighting needs.
Use Curtains or Blinds
You should move your plants to the shade whenever sunlight becomes too extreme. However, most of us don’t have the time and energy to do this daily.
Fortunately, you can use curtains or blinds to do the trick. Use black-out curtains if you want to block all the sunlight, but I recommend using lighter colors that can soften the light.
Use Grow Lights
Different plant species need varying hours of light to grow properly. However, keeping track of this may be unrealistic and exhausting for most of us.
Leave your plants indoors for one week, and you’ll find them yellowing and etiolating. Conversely, leave them outdoors for too long, and you’ll find them sunburned.
Fortunately, you can ensure your plants get the minimum amount of indoor lighting needed using grow lights. While there are plenty of grow lights to choose from, only a handful satisfy your plants’ needs.
Ideally, your grow lights should have the right spectrum that enables your plants to photosynthesize.
According to a 2019 study, plants grow best with grow lights having blue and blue-red spectral peaks. This is because blue light aids in chlorophyll production and root strengthening, while red light promotes flowering hence better propagation.
They should also have an automatic timer that allows you to control your plant’s light intake even when you’re not home.
If you want to explore your options for giving indoor plants enough light to grow, you can check out my other article here: How To Give Indoor Plants Enough Light To Grow
Final Thoughts
Plants, like their human owners, can get sunburned too. While they have mechanisms to prevent sunburn, too much sunlight can still harm them.
Fortunately, you can prevent this from happening by placing them in a cool area with ample shade, using UV-blocking curtains, and adjusting your watering schedule. Remember, sunburned plant parts can no longer recover, so prevention is better than cure.
