Why do orchid leaves curl and twist?
6 Reasons & Remedies
Just by looking at the orchid leaves, you can decipher where your orchid’s health stands and what it has been through in the past. Wilting leaves, spots, limp blossoms, and discolored leaves all tell stories.
Image Credit: Orchideria © 2020 All Rights Reserved.
Notice the curled middle orchid leaf and how it has twisted into itself
When I was watering one of my orchids this morning, I noticed the leaf was bunched together, like it had been twisted. It wasn’t flimsy or limp, but sturdy and otherwise healthy.
This curled orchid leaf was bothering me since I saw no exterior sign of pests or insects.
What are some of the culprits to curling and twisting of the orchid leaf?
The main reason orchid leaves curl is because the orchid leaf follows the light source when it grows. If the light source constantly changes, the orchid leaf will curl and twist, turning toward the brightest light. Another reason orchid leaves curl is the potting medium is loose, causing an unstable rooting system. Fungus problems and insects are the third and fourth culprits in why the orchid leaf curls and twists.
Let’s look at these four reasons one by one. At the end of the article, I'll add 2 more reasons that may be occurring, but less likely. I hesitated to add them to the list, but decided to anyway since just because they're less likely to occur, doesn't mean they don't. So... on to the 6 reasons of why orchid leaves curl.
Change in Light Source Cause Orchid Leaves to Curl
Orchids need sunlight to grow. In nature, the sunlight that reaches the tops of the leaves is filtered, having to pass through thousands of tree leaves that hang in the forest canopy above them. Even though the light is bright, it is filtered and the direct sun hardly reaches the leaves.
Orchid leaves will grow toward the brightest light source, trying to maximize their growth potential. Household plants will do this same routine too when they are in need of more light. Have you seen leaves in a peace lily that tilt toward the window? This means that they would prefer a brighter location inside your house.
Since orchids are extremely slow growers, their leaves don’t tilt and curl as much as the peace lilies do, but that doesn’t mean they don’t curl at all. They do. This happens because frequently after watering, we turn their pots. What was once a leaf that faced the sun, now is facing the living room couch. It will slowly try to move the leaves, but Phalaenopsis leaves are extremely thick and take time.
If you constantly rotate your pot, the leaf will suffer, curling into itself. The extra energy that is wasted trying to better take advantage of the sun’s rays will cost you. It might mean that the spike won’t develop this year, or that the leaf grows smaller. Energy is always in demand and your orchid is using the supply that it has to curl it’s leaves to where it used to be facing.
This is another angle of the same plant. Notice how the orchid leaf has twisted and curled under. It's still sturdy and strong, but bunched up, like someone squeezed it.
Image Credit: Orchideria © 2020 All Rights Reserved.
In summary, water your orchid but make a mental note of how the pot was sitting on the window sill before you watered it.
Don’t place it back into the window the way you feel fit. Always keep the orchid in the same direction, so the leaves won’t need to turn.
Incorrect Potting Medium Causes Orchid Leaves to Curl
When your orchid is potted in a medium that doesn’t provide stability, something for the roots to adhere to, your orchid will wobble in the pot until it finds that stability.
This unstable and uncertain media causes the orchid to look for another way to stop moving: the leaves. Orchid leaves will curl and twist to another position if they find that this new position will keep them from tilting over.
To maintain proper stability and balance, the orchid leaf curls, steadying itself inside the pot. This is a natural response to how they grow in nature. On the top of the tress, nestled away in the tree’s surface and in crevices and crannies, orchids will grow roots that attach to the bark.
They need to hold on for dear life since in the tropical and subtropical rainforest, it rains almost every day and pretty hard. The roots need to be strong to be able to withstand the impact of the pitter-patter of water droplets on their leaves.
When the roots aren’t strong, the orchid will risk falling off the tree and landing on the forest floor. Contrary to what many people think about the rainforest, the soil is very poor. It is not rich in nutrients because hardly any sun at all reaches the surface of the soil. Decomposing material and leaf litter will cover the forest floor, and it’s almost impossible to grow anything there.
There is an exception, which is terrestrial orchids. These orchids, few in number, have managed to survive poor lighting and even fewer nutrients. Their roots grow up over the soil and try to gather nutrients from the air.
Either way, the roots stabilize the orchids in nature. When this isn’t possible, they look for their leaves to provide some sense of “holding down their ground”, and will turn and curl until they find a position to stop wobbling. This is another reason you should stop repotting every time you think something is wrong with your orchid.
Let it be… Breathe in, breathe out… And keep the orchid roots growing strong in the correct potting medium.
Pests and Insects Cause Orchid Leaves to Curl
Depending on the size and shape of the curling of your leaf, pests that suck the nutrients out of the leaf may cause the orchid leaf to curl. Pests and insects are highly drawn to orchid honeydew sap, and the high content of nutritious food that is encountered in the leaves are especially appetizing to them.
If these pests, like aphids and mealybugs, are left on the leaf for extended periods of time, the place where they damaged the leaf may curl. This happens because the cell structures are damaged and the leaf cannot hold up a straight protective covering on the exterior of the leaf, making the damaged portion sink into the leaf and curl.
This also happens because the sap that once circulated inside the leaves through the xylem tissue has been interrupted and the plant cannot receive any more nutrients through that portion of the plant.
The orchid leaf curling in the presence of pests is different than the whole leaf curling, looking for light or trying to better position itself. The twisted portion of the leaf will only occur where the insects have damaged the plant cells.
Other Probable Causes for Orchid’s Leaves to Curl
If your orchid is changing color and yellowing, wilting, looking overall droopy, then the causes are not the ones mentioned above. For the list above, the leaves are still firm, green, and sturdy. When the leaf starts to present new symptoms to the curling, it could mean you have another problem. The main culprit is a fungus, that will enter through the roots and dry up the vascular system, known as the xylem, not allowing the orchid to receive any more nutrients.
In the third example, of orchid pests that munch on the leaves, the nutrients are being banned from only that point on the leaf and remain circumferenced by the lesion. Not so in the cause of fungus.
The fungus will start in the roots, and unlike bacterial root rot, fungus travels upward through the plant, destroying all in its path. The fungus will prevent any further nutrients to reach the leaf, and the entire leaf will wilt, turn yellow, curl, and eventually fall off.
At this point, it’s really hard to treat the orchid and salvage it. Once fungus settles in, the problem is generalized.
The last reason your orchid leaf might curl is over-watering. It’s more likely to get edema, but the orchid leaf can curl because of over-watering too. If you want to read more about EDEMA, and what that is, this article on edema
goes over the causes, how to fix it, and how to prevent it from happening again.
But once the edema has happened, the orchid leaf will curl on the very tips. They’ll curl under as if they are suffering from over-fertilizing. The truth is, that if you are over-watering, and you use fertilizer in each watering, then you are also over-fertilizing. The symptoms go hand in hand.
The sixth and last cause is that when your orchid was shipped, it was smashed into a box and filled with Styrofoam peanuts or wrapped tightly in a newspaper. If the orchid took a little longer in the mail to be delivered, the pressure that was applied during packing (which is a good thing to prevent it from further damage of being beaten up against the sides of the box) dented the leaves and they curled.
This temporary curl may not be as temporary as you’d like it to be. Since Phalaenopsis and Cattleya orchids have thicker, unmanageable leaves, this constant pressure has deformed the leaf, making it curl.
These are the main six causes of the curling of orchid leaves. Once you figure out what has happened, then you well on your way to fix it. The downside is that once an orchid leaf curls, it doesn’t straighten out later. It will remain curled until the end of that leaf’s life.
If you have any questions about other possible causes for an orchid leaf to curl, please mention below in the comments. I very well could have missed or overlooked a possible cause and love to interact with other orchid enthusiasts. So please comment below and send a thumbs up. Further Reading Suggestions:
One orchid fungus that attacks the leaf and causes it to wilt is called Fusarium Wilt. You can read an article about that here
, written by Planet Neutral Research Center. Even though it’s aimed for general crops and plantations, the fungus is the same and acts the same in orchids.