Calathea yellow leaves are a major concern as it is indicative of the plant being under stress due to inconsistent watering, lighting issues, humidity and inappropriate soil. It is the key indication that all is not well for the plant and that the plant needs immediate attention before it hampers its overall health.
Read our one-stop plant care guide and know what you should do. In this article, we have the most common causes with easy tips and techniques to not only fix the problem, but also prevent it from happening in the future.
Why Are the Calathea Yellow Leaves?
Calathea leaves are turning yellow due to over or under-watering the plant, poor drainage, use of heavy soils, temperature fluctuations, fertilizer and light issues and even pest infestations and diseases. In addition, low humidity, over-fertilizing, nutrient deficiency, repotting stress, too much sun would cause this issue as well.
– Under Watering
You are most likely to see your calathea plant leaves develop yellowing leaves if you have been under watering the plant. When the soil gets extremely dehydrated, to the point of going bone dry, the roots won’t be able to draw in the required nutrients. This puts the plant under stress, making it weak and limp, and leaves would change their color.
The first sign of dehydration of calathea orbifolia leaves turning yellow can be typically seen on the bottom section of the stem. You may very often notice this occurs on hot, sultry days when the moisture in the air is minimal as well. Coupled with dry air, and sometimes soil that drains out water way too fast, the tendency for an extremely dry situation arises.
– Overwatering
One of the most common causes and mistakes that people do that leads to rattlesnake plant yellow leaves is to overwater the plant in a quest to keep it healthy and thriving.
However, the plant is sensitive to excess moisture and the first sign that it is under stress due to this cause is the yellowing of leaves. Excess moisture makes the plant susceptible to fungal infections and root rot, so no nutrients will reach the leaves, and it would be stressful to the plant.
When you pour so much water, there is a lack of oxygen for the plant due to the inability of the roots to take in the required dose from overly moist soil. The yellowing sets in as soon as the plant gets impacted by root rot. Additionally, you will also notice that the stems would become soft and limp to the touch.
– Poor Water Quality
Another thing is the type of water used to water calathea. Most people just use tap water to water their plants, but this isn’t always a good option. Tap water contains chemicals that can be bad for the plant. Some of these are chlorine and various types of minerals that are harmful to the plant.
– Cold Temperatures
Another common reason for yellowing calathea leaves is extremely cold weather and rapid temperature fluctuations. The plant seldom likes cold temperature below 60 degrees Fahrenheit and is stressed under chilly winds, cold droughts and frost conditions.
In this case, you will notice the bottom leaves of the stem turning yellow in such a case. Moreover, sudden fluctuations in temperature too can easily stress out the plant.
Apart from yellowing leaves, you will also notice droopy and wilted foliage and sometimes burnt yellow leaf edges, which slowly turn into brown edges. The plant’s other functions too get affected such as photosynthesis chlorophyll biosynthesis and transpiration.
Similar to extreme cold, Calathea leaves can also turn yellow due to heat stress. Extreme heat causes the degradation of chlorophyll and puts the plant under stress, so that’s why your calathea zebrina yellow and brown edges occur.
– Too Much Direct Sunlight
Exposing your plant to way too much sunlight? Now that could have consequences on the leaves by turning them yellow.
This gorgeous plant is a tropical rainforest one and is used to receiving diffused sunlight through the larger trees that form a natural canopy over it. The dappled light from larger tropical plants enables them to receive bright yet indirect light.
This means that if you are growing Calathea in your garden, you have to mimic its natural environment otherwise you are going to end up putting the plant under stressful conditions and the result being yellowed leaves and Calathea leaves drooping.
– Low Humidity
If the air around the Calathea lacks humidity, the leaves turn yellow. Again, you must keep in m ind that the tropical calathea prefers humidity levels between a range of 65 percent to 80 percent, which is a high level of moisture.
The moderate humidity helps to keep the plant well-hydrated and the foliage lush green. In addition, dry air additionally makes the Calathea leaves turn brown and brittle, as a result of the yellow leaves.
– Over-Fertilizing
Much as the calathea prefers over-the-top fertilizer use, overuse dehydrates that plant. It results in the Calathea leaves curling up and turning yellow.
Moreover, fertilizing in the colder months of winter results in an excess salt build-up at the roots, leading to discoloration of the foliage. Keep in mind that you may also notice other signs of over-fertilizing, such as a layer of white crust-like residue on the soil and the leaves.
– Soil Conditions
If you are growing your Calathea in a potting mix that is heavy, loamy, or clayey, then you are most likely going to witness the leaves turning yellow.
This is because this kind of soil retains a lot of moisture, thereby preventing the roots from taking in oxygen and nutrients from the soil. Basically the water you are irrigating with will stay on top and get trapped due to the soil’s quality.
They are seldom well-draining, which creates an environment where the roots end up sitting in water for a long time. Furthermore, apart from the soil, your pot too needs to have proper well-draining holes, not clogged by debris or gravel.
– Nutrient Deficiency
A Calathea plant deficient in magnesium, manganese nitrogen, potassium and iron can lead to yellowed leaves. Iron is an important component for the plant to sustain lush green foliage and a deficiency will not only discolor leaves but will also make them drop prematurely. Additionally, you may also notice droopy leaves, if the nourishment isn’t sufficient.
– Repotting Stress
Calathea leaves may turn yellow as a result of stress after repotting. This isn’t entirely a sign of danger to the plant, as it is temporary. Very often, in a few days, you will see it limp back to life. This is because the plant is in a new environment where the conditions are new as well, and it needs some time to adjust.
– Pest Infestation
Common garden pests such as spider mites can infect calathea and discolor leaves. These pests extract the sap from the stems and leaves and leave behind a white web-like substance.
If left untreated, pests can create havoc on your calathea, destroying the plant in its entirety. You will most likely spot these on the underside of leaves and stems and as the infestation manifests across the foliage, the weak plant will tend to display yellow spots.
– Fusarium Disease
The Fusarium disease or otherwise also known as the fusarium wilt is a fungal disease of the plant causing yellowed leaves. This disease can spread through infected tools, spores in the air or nearby infected plants. It not only discolors leaves but also leads to slow or stunted growth, and defoliation and over time it can even kill the plant as a whole.
– Rootbound Plant
If you notice roots sticking out of drainage holes, along with yellowed leaves, your Calathea is root bound and needs to be repotted at the earliest.
A root-bound plant would get compacted within the soil, which would lead it to be unable to absorb the nutrients from the soil and even retaining way too much moisture around the roots. Overall, these conditions tend to stress out the plant leading to calathea leaves losing color as it ends up growing in a container with poor drainage.
– Insufficient Light
Note that if overexposure to light can hamper the growth of the plant, insufficient light is equally a problem.
You will begin to notice the Calathea leaves turning yellow if your plant is being grown in a dark or dingy corner or away from bright sunlight. Calathea plants need that bright light to sustain their robust green foliage, otherwise, they tend to discolor, wilt and fade away.
How To Fix the Problem?
To fix this problem you must first scale back on the watering, then change the soil and pot to a proper one with drainage. Additionally, provide the right light, fertilizer and humidity, repot ever few years, treat the fungal diseases, use the right water, and get rid of the pests.
– Handling an Overwatered Plant
Scale back on the watering as soon as you realize that you have overwatered. Allow the soil to dry out completely by poking tiny holes in it, which will allow air to enter and speed up evaporation.
What you must do is to adjust your watering Calathea schedule to once a week or until the top inch of the soil dries up. Do a simple finger test before you water Calathea, by pressing your finger an inch into the soil in order to feel the moisture, and if it comes out dry, you can add in more water when the plant is thirsty.
– Change the Soil and Check Pot Drainage
Keep the soil light and well-draining by using a potting mix with perlite and peat. You could also better the soil drainage by including some orchid bark or worm castings along which makes the soil more coarse keeping it aerated. Keep the soil slightly acidic between a pH of 6.0 to 6.5, and this is a prominent need of the Calathea care.
Additionally, the pot or container that you are using must have proper drainage holes to permit free flow out of water. Look out for debris, or gravel that may be blocking it and clear them out from time to time. This is important because the roots won’t be sitting in too much water, and they wouldn’t be damaged in the long run.
– Providing the Right Level of Light
Place your plant in a semi-shaded spot such as a patio, driveway or balcony so that it can receive bright yet dappled light. Alternatively, create a greenhouse effect by placing a garden sheet over it, permitting diffused light to penetrate through the material.
You may also place the Calathea under larger plants to recreate a tropical environment permitting light to peep through the larger leaves above. However, you must avoid dark dingy corners especially indoors.
On the other hand, when it comes to growing it indoor, you may move the plant near an east-facing window, behind sheer curtains so that it could benefit from the gentle rays of the morning sun, that aren’t heavy for the plant.
– Protect From Extremes in Temperature
Move the plant indoors when the weather outside is either too hot or too cold. The plant thrives best within its normal range and outside this, it will struggle and be stressed. Keep it away from cold drafts, frost conditions and chilly winds by moving it into a closed spot and placing grow lights over it to bloom new green leaves.
– Tackle Humidity
Increase humidity around the plant by misting it often. This will not only kick in the required moisture, but will also keep the foliage looking clean. Alternatively, you could even place a pebble tray below the pot. Just as the water that’s in the tray evaporates, it increases humidity around the plant, or maybe even invest in a humidifier.
You could also consider grouping the plant along with other larger plants to benefit from the collective humidity of all of them. Place the plant in a well-ventilated area where there is adequate air circulation to prevent any risk of over-humidity on the plant. This will help tackle Calathea leaves turning brown and yellow.
– Repot Every Few Years
Calathea roots can get dense and often block drainage holes getting root bound. It is thus recommended to repot the plant once every two years, to a pot one size bigger. Note that you shouldn’t use a very big pot, as this would mean putting the roots at risk of sitting in too much water.
To repot, you must simply remove the plant from the old pot and loosen the roots a bit. Remove the extra soil around. It. This is the time to also inspect for any root rot or blackened sections which can be gently snipped off with a sterile garden pruner. and then simply repot in a light potting soil watering to keep the soil just slightly moist.
– Get Rid of Pests
Pests such as spider mites need to be gotten rid of as soon as you spot them. Isolate the plant at first sight of the infestation to prevent its spread to other nearby foliage. Blast a jet spray of water, with the help of a garden hose, on the infected zone, as this will make the pests fall off.
Alternatively, you can even use an organic liquid such as neem oil whose smell repels these pests or a soapy liquid to get rid of the pests. Repeat the application for three weeks, or until all of the pests fall off. Prevent any pest infestation by keeping the plant dust free, as you may mist it regularly and clean by wiping the leaves using a damp cloth to keep the foliage clean.
– Fertilize Right
The right formula for the calathea is a general-purpose well-balanced houseplant fertilizer with an NPK ratio of 10-10-10. Dilute this in a gallon of water before application.
The ideal season or month to fertilize is in the growing months of spring, preferably twice during the season. Note that you must never fertilize in the fall or winter months, which could lead to salt buildup more easily.
– Treating Fungal Diseases
To treat fungal diseases such as fusarium disease, the first, and most important thing that you must do is to prune the infected sections as soon as spotted and destroy them away from all plant foliage.
Remember to first isolate the plant and spray an organic fungicide available in most gardening stores as per the dosage. Scale back on the watering when fungal diseases have been detected as excess moisture makes the infection spread faster.
– Use the Right Water
Use distilled water that can be obtained from the local grocery store or department store. Alternatively, collect and use rainwater. You could also set some tap water aside as it will sit at room temperature for a few hours before watering your calathea with it to reduce the risk of exposing the plant to harmful chemicals.
However, this can be a bit cumbersome and many find it easier to just buy distilled water. You can also obtain a water filtration system that removes chemicals and accumulated minerals from the water. A good water filtration system can be a little expensive, but it has advantages that involve safely watering your plants.
– Pruning
You may also prune the yellow leaves, as it improves and stimulates fresh growth. As the plant matures and the leaves age, this is because it is very common for some outer leaves to turn yellow or brown.
Note that yellow or dead leaves will never turn green again. When they lose chloroform, the plants abandon them and move on, so prune for a fresher start.
Using sharp scissors, cut the leaves at the base where they meet the main stem to get calathea new leaves pale green and healthy.
Conclusion
You have read in this detailed guide what’s causing your Calathea plant leaves to turn yellow.
Let us summarize all that we have learned in this section below.
- Calathea leaves tend to turn yellow when they are subject to stressful conditions. As a tropical plant. They thrive best in an environment closest to their native.
- The plant requires bright yet indirect light, thus growing the plant in a spot where there aren’t too many sun rays nor a dark and dingy spot.
- The plant requires moderate levels of humidity so if you are growing the plant in a dry zone, retain moisture by misting the plant or by using a pebble tray.
- Calathea cannot tolerate fluctuations in temperature or extreme chills. Thus move the plant indoors in winter growing them under artificial grow lights.
- Avoid overfertilizing the plant or feeding in winter as this could result in a salt build-up in the soil. Use a well-balanced 20-20-20 formula in the growing months of spring and summer.
Now that you have understood the problem and know all the easy ways to tackle it, you can fix it all by yourself in a hassle-free manner. So adorn your home or garden with the attractive and robust Calathea plant.
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