Succulents are native to some of the driest and most arid places in the world, and are more tolerant of constant bright sunlight than most other types of plants.
But, even though succulents enjoy sunlight, too much exposure can still be harmful to them, and can cause sunburn.
The longer the problem is left unchecked, the more permanent the sun damage will be.
In this article, we will discuss the signs of sunburn to watch out for in succulents, as well as how to treat it. If you currently have this problem and wish to know how to address it, then keep reading.
What causes sunburn in succulents?
The main cause of sunburn in succulents is too much exposure to heat and sunlight.
This can be from the UV rays of the sun or even from the heat produced by artificial light from a grow light.
If the succulent has been in a shadier environment for a while, then transferring it to a spot when it suddenly gets direct sunlight can also lead to sunburn. Even keeping it indoors on a windowsill that lets in too much sunlight can cause sun damage.
Although succulents like lots of sunlight, many still need to have a few hours of shade, especially in the middle of the day or early afternoon when the sun is at its highest.
A succulent’s propensity for sun damage also depends on what kind of succulent it is. Some species can be more sensitive to sun and heat, while others can be more tolerant.
How to spot sunburn in succulents
Brown, black and yellow spots on the foliage
The presence of these brown, black and yellow spots on your succulent’s leaves means that it has severe burns. This discoloration is an indication of considerable damage to the plant’s cells.
Sometimes, the sun damaged area may appear pink or purple on the foliage as well.
Unfortunately, this degree of damage is usually permanent and cannot be reversed. It will only be removed when those leaves grow old and are replaced by new leaves.
Spots on leaves that are lighter than the rest of the leaves
Some of these sun damage spots can even look white. When you touch these lighter spots, they will have a rough texture as opposed to the usual smooth texture of healthy leaves.
These sun damage spots are in the early stages and are not yet considered severe.
The succulent has dry parts
Another sign that your succulent is getting too much light is when parts of the plant look like they have dried out. These dry parts of a sun-damaged succulent go hand in hand with severe burns and permanent damage.
Dried-out leaves and foliage will often fall off the plant.
How to treat sunburn in succulents
As mentioned above, minor burns on succulents present as the lightening of some parts of the leaves, as well as the presence of white spots.
If you see these white spots on your plant, transfer it immediately to a shadier spot to prevent any further damage.
Touch the potting mix in the plant’s pot. If the potting mix is dry to the touch, water the plant to help it recover from the sunburn.
Do not move the succulent from the shadier area for at least three days.
Gradually reacclimatize the plant to more and more light every day, until it can tolerate longer hours under the sun. Just make sure not to go back to the hours of sunlight that caused the sunburn in the first place.
If you were able to catch the sunburn in its early stages, there should not be any permanent damage on the foliage and the white spots should barely be noticeable after a few months.
Severe burns are indicated by brown or black spots and dried-out parts on the succulent.
If you suspect severe burns on your succulent, transfer it immediately to a shadier spot.
Touch the potting mix in the pot and water it if it feels dry to the touch.
If the succulent looks extremely dried out, you might have to remove it from its potting mix, cleaning the potting mix from the plant’s roots, and soak the roots in a glass of water for a few days or weeks until the plant has fully recovered.
After a week of rehabilitating the succulent, you can prune off the severely damaged foliage. Remember that severely damaged leaves do not recover, so unless you are going to wait for them to be replaced by new leaves, just prune them off.
When the succulent has fully recovered, you can gradually acclimatize it to more and more sunlight each day. Just remember not to expose it to as much light as you did to cause the sunburn.
How to avoid sunburn in succulents
- Acclimatize the succulent
Gradually increasing your succulent’s exposure to light is the key to preventing sunburn.
This is especially important for succulents that you have just brought home from the store or the nursery. Take note of the kind of light the succulent is getting in the store and try to replicate that for the first couple of weeks, so that the plant does not go into shock.
Keep it away from direct sunlight at first, and every day you can gradually increase the number of hours of sunlight it gets.
Be on the lookout for any effects caused by the increased sunlight. If white spots develop, this means the plant has not yet adapted and you need to reduce the sun exposure a bit.
It really is a trial and error scenario, so find what works for your plant and stick to that.
- Caring for the succulent’s wax layer
The epicuticular wax layer, or farina, is a natural sunscreen that some succulents have. This layer protects the succulent from the harsh ultraviolet rays of the sun.
One of the best ways to avoid sunburn on your succulents is to make sure that the wax layer is intact.
Refrain from constantly touching your succulent’s leaves and stems, because the friction can remove the wax layer.
- Avoid the magnifying glass effect
The magnifying glass effect occurs in the presence of crystal or even water droplets. This means that glass windows and water droplets amplify the light and the heat that reaches your plant; hence increasing the likelihood of sunburn.
To avoid sunburn due to the magnifying glass effect, keep the succulent away from windows that let in bright and intense sunlight.
If you keep your succulents in a terrarium, only expose the terrarium to sunlight when the sun is not at its brightest. This is because the terrarium glass can also act as a magnifying glass.
Do not water your succulents from above, because water droplets will remain on the leaves and can also act as a magnifying glass. They can then leave small spots on your succulent’s leaves.
- Spray insecticide only in the late afternoon
When your succulent is sprayed with insecticide, it becomes sensitive to light and may burn easily. This is why it is advised to do any spraying in the late afternoon so that the plant has the entire night to recover.
You can also just move the plant to a shadier spot while you treat it, to further lower the risk of sunburn due to insecticide spray.
- Protect the succulent from the sun and heat
If the above measures are not enough to protect your succulents, you might need to actively protect them from the sun and heat.
In the spring and summer, when the days are longer and hotter, you might need to take the following precautions:
Water the succulents more often than during the fall and winter months.
If the weather is very hot and sunny, your succulents may be better off in a shady spot for most of the day. Do not worry about the plants not getting enough light; they will be completely fine and will adjust to the new situation.
You can also actively protect your succulents using awnings, shade cloths or a screen.
A sunburnt succulent can present either with minor burns such as white spots and lightened foliage, or with severe burns such as brown or black spots.
Treat a sunburnt succulent by transferring it immediately to a shady spot and watering it if the potting mix is dry.
For minor burns, keep the plant in low light for a few days and gradually reacclimatize it to more light when it has fully recovered.
For severe burns, you might need to give the plant water therapy to help it recover better. Prune off any severely damaged foliage, because those plant parts will not be able to recover.
Once the plant has recovered fully, gradually expose it to more and more sunlight until it has reacclimatized.
Image: istockphoto.com / Peerakorn Chotthanawarapong