Calatheas can be rather dramatic plants. If they aren’t getting the care they want, they will show it fast. Yellowing of the leaves is pretty common, so you can be sure you are not alone in asking yourself why are your calathea leaves turning yellow.
Read on to find out what the causes are for this issue to happen and what you can do to fix it and prevent it in the future.
These plants are known for their wonderful foliage, both shape, and pattern. Keep the plant happy, and it will have healthy foliage.
Why are My Calathea Leaves Turning Yellow?
These plants are pretty great at letting their owners know when their needs aren’t being meet, most commonly through their foliage. One of the ways is the yellowing of calathea leaves.
A yellow leaf is a struggling leaf, always. A partially yellow leaf might not die off anytime soon. However, a fully yellow leaf is done for.
If you start noticing yellow leaves on your plant, something might be off with how you are caring for it. These plants can quickly deteriorate if they aren’t getting proper care.
Read: Calathea plant care tips
Figuring out the cause for your calathea leaves turning yellow is important as this most likely indicates a problem.
The only time this isn’t an indication of a problem is when old leaves die out or if you tested a solution (for cleaning or pest control) on one of the leaves and the plant didn’t like it.
If You Just Brought Your Plant Home
Whenever a plant is moved from one environment to another, it can get stressed. The bigger the change in conditions (humidity, temperature, light, aeration), the greater the chance for stress and stress-related issues.
It can take a couple of weeks for your plant to get used to its new home, and it can struggle a little during that time. This can mean a leaf or two turning yellow, too, even with proper care if there are no other signs of trouble.
You should still keep an eye on your plant to see if the issue persists (more leaves turn yellow) or if you find another cause for it (like spotting pests).
Similarly, repotting a plant at any time can cause it to stress too, and it will need time to adjust. If you spot a few Calathea leaves turning yellow after you repot, take extra care of your plant, make all other conditions as optimal as possible.
1. Old Leaves Dying Out
Before we get into the more serious causes that might cause your calathea leaves to turn yellow, we should note that it is normal for old Calathea leaves to turn yellow and fall off.
If you only see a yellow leaf occasionally and only at the bottom of the plant, but the plant is otherwise healthy, this can be because the leaf is dying out as part of its natural cycle.
While this might well be the case, it’s always best to think about other issues that might cause and act on them rather than being sorry later.
Prune away the yellow leaves from your Calathea and you should see new growth soon.
2. Calathea Leaves Turning Yellow due to Overwatering? What about under-watering?
Overwatering is a plant killer, so this is the first thing you need to rule out.
Calatheas are really easy to overwater as they require their soil to be constantly moist, but they don’t like to grow in soil that is too wet. If the soil is too saturated and soggy, root rot can develop pretty fast, and your plant will suffer, and if not acted upon, will die.
If you are overwatering your plant, one of the first signs can be the leaves’ yellowing.
Check the soil. If it’s still wet days after watering, you can be sure you are overwatering your plant. Inspect the roots for signs of rot root and treat accordingly. Dry out soil or repot the plant with new soil.
Adjust your watering routine to avoid overwatering your plant in the future (it’s how you water, not how much you water).
Prune away the yellow leaves on your Calathea plant. They are dead weight, and pruning them will let the plant focus its energy on growing new leaves.
Same as overwatering, under-watering can cause calathea leaves yellowing too.
Calatheas like their medium constantly damp, you shouldn’t let more than the top layer dry out between waterings.
While the tag that came with the plant probably said you should water once per week, you need to figure out the optimal watering routine for your plant and it might be different to what it says on the tag. Depending on the conditions in your home, you might need to water twice per week or only once per two weeks or so.
Make sure you have soil that is well-draining and is great at retaining moisture. There are tropical houseplant soil mixes readily available in gardening stores, and that soil is usually fine.
The pot needs to have drainage holes. This is a must and is not optional. If you purchased the plant and repotted it into a decorative pot without drainage holes, this is killing your plant.
3. Water you use
Calatheas are really sensitive to water you use for watering. They can react badly to chemicals and minerals in your tap water.
Getting brown edges or spots on leaves is almost a given if you use tap water. If they really dislike your water, the leaves will suffer more. They will turn yellow and slowly die.
If you are set on using tap water, let it sit for a day or more before watering to de-chlorinate.
Using filtered water, rainwater or even distilled water will make your Calathea happy. The water should also be at room temperature.
Calatheas are prone to many pests, but spider mites are usually the culprit for their leaves going yellow.
In theory, spider mites don’t like high humidity, and while that is true, it seems they are willing to suffer it when it comes to Calatheas. They can attack the plant even if the humidity is high.
When you spot the yellowing of the Calathea leaves, carefully check the underside of the leaves as well as the stems. Spider mites are hard to spot.
If the leaves are yellowing, chances are the infestation is already big enough for the signature spider mite webbing to appear – and that one is hard to miss.
Even if you don’t see the webbing, carefully check the plant, if possible, with a magnifying glass. If you see tiny spots moving, and the spots are either red, brown, white, or black, you probably have spider mites.
They can be a pain to get rid of, and you will have to be diligent. You can use organic means to get rid of them or opt for a pesticide.
Prune the yellow leaves from your Calathea and treat the plant accordingly.
Move the plant away from other plants until you are done treating it. Check other plants for pests, too, as these can spread fairly quickly. We would advise using neem oil and spray plants that don’t have pests as a preventive measure.
5. Chemical Burn
If you treated your plant for pests, used a solution of any kind to prevent pests, washed your plant with soap mixture, alcohol, or used anything else that gets applied on the foliage, and the leaves can get damaged.
If you aren’t dealing with an emergency (pest control), it’s best to try out the solution of any kind on one leaf before using it on the whole plant. The plant might like 9 different products but will react on the 10th.
This damage doesn’t necessarily kill the leaf, it can only partially damage it, and the leaf will still live on.
You can prune away the yellow leaf or a couple if you wish.
6. Can fertilizer cause Calathea leaves to turn yellow?
Overfeeding calatheas is a more common issue than not fertilizing them enough. Too little fertilizer may cause yellow spots on leaves.
We recommend using about half the recommended dosage of fertilizer with calatheas as they are one of the more sensitive plants.
If you have been regularly fertilizing, and overwatering is not an issue, the yellow leaves on calathea are likely a result of overfeeding.
The excess minerals and salts build up in the soil, and as time passes, this will negatively affect your plant.
Flush the soil, let the water run through the drainage holes for a minute or two (be careful not to let the soil go through drainage holes). This will wash out some of the mineral and salt buildups from the soil from overfertilizing.
Refrain from fertilizing for a couple of months, and use less fertilizer in the future. If you have fish, you can also consider using aquarium water for watering instead of using fertilizer.
You can remove the yellow leaves from your calathea as they won’t be coming back.
7. Humidity and air flow
Air surrounding your plant plays an important role. Leaves on your calathea can turn yellow if the plant isn’t getting the humidity it wants.
As tropical plants, Calatheas love high humidity and can get stressed if air humidity is not high enough.
They will tolerate lower than ideal humidity, some types of Calatheas more than others. However, if the humidity is too low, this will show in edges and tips of calathea browning and leaves yellowing, on the edges first.
Inside the home, the ideal level of humidity would be anywhere from 50% to 70% (they would prefer it higher but that would be unhealthy for you). Some varieties do well with 50%, while others might show signs of stress with humidity being close to 50%.
To avoid the leaves on your calathea yellowing in the future, increase the room’s air humidity or around the plants.
Calatheas like to be in a well ventilated area but will suffer fast if they are exposed to drafts.
8. Insufficient Light
Calatheas need bright indirect light throughout the day. If your plant isn’t getting enough light, it will stunt the growth, and the leaves’ yellowing may appear.
The further away from the window, the less light your plant gets. If you notice your plant struggling, move it closer to the window. It will appreciate some morning sun.
The direct strong afternoon sun will harm it. If you have it in a spot with direct sun, make sure you filter the light. Direct light or too much light will cause the leaves to burn and lose the colors (in the case of Calathea Ornata, the pink stripes will fade and turn white).
Another cause for calathea leaves turning yellow are rapid temperature changes and temperatures that are too low.
Average warm temperatures are ideal for your plant. If the temperatures are too low, falling below 60°F (15°C), the plant will deteriorate.
Cold draughts will cause stress, too, and the bottom leaves are usually the ones that turn yellow.
If your plant is otherwise healthy it should be able to fight off diseases and infections.
However, if the conditions aren’t ideal, it can be prone to some diseases, and some of those will also lead to your calathea leaves yellowing. Fungal diseases can be common if the humidity is too high and there is no ventilation in the room.
If you notice yellow streaks on the plant, distorted leaves, and stunted growth, you may be dealing with a viral infection.
Pests can rarely infect your plant with a virus, or you have brought home a plant that was already infected. There is no way to treat it, so it’s best to discard the plants before other plants become infected.
11. Mechanical injury
If you have pets, cats especially, or kids, mechanical injury of the stem can also be a culprit. Examine the stems and see if they are damaged.
New Leaf on Calathea Yellow?
If your plant is otherwise healthy, but you notice the new leaf that has grown is yellow, this is likely due to conditions not being optimal during its growth.
With proper care this will be a one off thing and future growth should be normal.
Can Yellow Leaf on Calathea Turn Green Again?
No. Once the leaf is yellow, there is no turning back. If the whole leaf turned yellow, it will dry up and fall off sooner or later.
If the leaf is partially yellow, the green part will still do it’s job and the leaf will live on. Depending on the cause, the yellowing of that calathea leaf might slowly continue or completely stop.