One of the primary reasons for keeping Caladiums as houseplants is their stunning foliage. Because of that, if the leaves start to turn yellow, this plant instantly loses much of its appeal.
Yellowing of caladium leaves can be caused by manganese, zinc, nitrogen, and iron deficiency. Overwatering and underwatering often lie at the heart of this issue. Make sure to use distilled water only when the top 1-2 inches of soil are completely dry, and bright indirect light to keep the leaves from yellowing.
At this stage, the main factor to bear in mind is that a solution is possible so don’t give up on that unhappy-looking plant just yet.
Once you have read this article, watering correctly will cease to be a mystery and you will easily be able to maintain your plant in peak condition.
What Causes Caladium Leaves to Turn Yellow?
Overwatering
Because this is probably the most common cause of yellow leaves, we will deal with it first. If your caladium receives too much water the soil becomes soggy which impedes oxygen flow.
Effectively, what happens is that the plant begins to drown. As this problem gets worse, it can lead to fungal diseases and root rot which we will deal with shortly.
For now, what you need to know is that if Caladium’s leaves start to droop and go yellow the first thing to check should be the soil.
Poke your finger into the growing medium and you will quickly feel if the soil is just damp or if it is wet and boggy.
If it is the latter, you can be certain that this is the root cause of your plant’s dissatisfaction with the environment around it. The presence of a wet smell and gray mold on the soil’s surface are two other telltale signs of rotting.
Solution
If your Caladium is overwatered what you are going to need to do is to let the plant start drying out.
You don’t want to hang about on this one and will need to start taking action as soon as you have identified what the problem is.
Stop watering for the time being and ensure that there is sufficient drainage in the base of the pot for that excess water to drain away freely.
If the plant is standing in a saucer containing water, that will be impeding the moisture from escaping from the soil. Empty that saucer and make sure you keep emptying it until all the excess water has drained away.
If the problem has not become too advanced, that is all you will need to do and quite soon the plant will begin to recover.
In severe cases, where the soil is extremely wet and the plant is looking very distressed, remove it from its pot and gently remove all of the loosest wet soil from around the roots.
After that, stand the plant on some newspaper and allow the root ball to dry before repotting into fresh potting soil with good drainage capacity.
You won’t need to water immediately after re-potting because the potting mix is likely to be slightly damp and there will be enough moisture there already for your Caladium to start making its recovery.
Although the plant should gradually begin to recuperate after these interventions, those yellow leaves will never regain their previous appearance and they can be cut off near the base of the stem.
Underwatering
The next most common reason for those sad caladium yellow leaves is underwatering. It may seem ironic that the two most likely causes for those sad yellow leaves result from such opposite extremes, but that actually is the case.
Once again, your first reaction upon seeing those yellow leaves should be to poke your finger into the soil to assess the moisture level.
You can purchase and use a moisture meter, but this low-tech method is perfectly effective and cost-free.
If the soil feels dry and sandy, then you can be sure that your Caladium is lacking water and is unable to transfer nutrients to its leaves. In the first instance, water the plant immediately.
Correct Watering Procedure
In both of the above cases, you will prevent re-occurrences of the problem by learning to water correctly. Don’t worry, it’s really easy.
Get into the habit of regularly testing the soil to ascertain if it is time to water. You can use the water meter or the bog-standard finger in the soil technique.
Both are accurate enough to maintain a healthy Caladium. What you are trying to achieve is a situation where the soil remains moist but not wet.
If you test the soil regularly, you will soon become quite skilled at doing this. Once the soil an inch or so beneath the surface is dry, it is time to water. Place the pot in a basin or sink and water generously.
Keep watering until you are sure that excess water is flowing through the drainage holes in the base of the pot. After that, stop watering and allow the excess water to drain away fully before returning your Caladium to its regular position.
Don’t imagine that you will be able to work to a regular schedule because that’s not how things work.
Depending on several different factors, sometimes your plants will need to be watered often, and at others less so.
Regularly testing the soil is the most reliable method of getting the timing right and keeping your Caladium happy.
Apply the water at the base of the plant, trying not to get the leaves wet as this can promote fungal disease. Another important tip is to use filtered water or captured rainwater.
Regular tap water contains chlorine which builds up in the soil over time and becomes unhealthy for pot plants.
I am lucky enough to be able to use river water and this has really made a difference to the long-term health of my indoor plants.
Leaf Burn and Drying Out
These are shade-loving plants and too much sun is another factor that might come into play when leaves start to show signs of distress.
What actually happens when these plants receive too much light is that they become sunburned.
In addition to yellowing and wilting, you may notice burned patches on the leaves that have become crisp to the touch.
As well as actually burning the leaves, too much light also stresses the plant because it is forced to increase its rate of transpiration as it attempts to respond to adverse conditions.
Solution
To avoid this issue, all you need to do is place your Caladium in the proper position when you first place it. Generally, any location that receives bright light but not direct sunlight will suffice to keep your plant happy. Take care that if you place your plant near a window, it does not receive an unexpected blast of direct sunlight, even if it is only for a few hours per day. Generally, east-facing windowsills work quite well.
Rust and Southern Blight
Both of these problems are the result of fungal disease. Rust manifests itself as rust-colored dots on the leaf which gradually evolve into yellow blister-like bumps.
Southern Blight, on the other hand, tends to turn the leaves a mottled yellow and distort them.
If either of these fungal infections becomes established your caladium will begin to wilt and after that will quickly die.
Control and Management
The main source of both of these fungal infections tends to start in the soil. The fungus remains dormant and then spreads rapidly when conditions are right.
There is no effective way to know whether the fungus attacking your plant was in your soil or was already in the tuber when planted.
The gardener can try to deal with the problem and ensure that conditions are not in the fungus’s favor.
These pathogens thrive in wet soil. As we have seen, this weakens the plant as well, making your Caladium even more vulnerable to infection.
By using a good watering technique, you lower the risk to your Caladium. If your plant is still targeted, you can try standing the tuber in water heated to 122°F (50°C) for thirty minutes.
After that, repot it into fresh sterilized potting soil. Spraying or wiping the leaves with neem oil will also help to prevent fungal infections.
Botrytis Blight
This is another fungal disease that prefers tender plant material so may first be noticed on the newer leaves It manifests as lesions on the leaf which start as caramel color and then mature to form a gray mold.
Control and Management
Because the disease is highly contagious, you may want to start by isolating your Caladium from any other plants in your collection to avoid spreading it.
Keep the area around the plant well ventilated, and avoid wetting the leaves with water when watering.
If you see signs of infection, cut away damaged or fallen material immediately and destroy it. Treat the leaves with neem oil as this offers natural anti-fungal properties.
In the case of all of the fungal infections we have just looked at, your Caladium will have much better chances of defending itself and recovering if it is in good health.
Root Rot
Few things can kill your Caladium quicker than root rot can. Almost always related to overwatering, the roots begin to rot and then die.
This manifests itself in the upper parts of the plant where the leaves, deprived of nutrients and oxygen, turn yellow and collapse.
Control and Management
If you suspect that your caladium has root rot then tap the plant from its pot and examine the roots. Healthy roots are firm and white, whereas those infected by root rot are brown and flaccid.
Remove as much of the wet soil as possible. Any root material that is not healthy can be cut away and disposed of because it will not recover and is no longer serving any purpose. You need to cut back those damaged sections until your reach healthy plant material.
Dry the root ball out and pot the plant into a sterile pot using new potting soil. Don’t water the plant immediately after re-potting but wait until the soil is dry below the surface.
Insect Infestation Cause Caladium Yellow Leaves
In peak condition, your Caladium will usually remain pest-free. Among house plants, there are three main culprits that you will need to be aware of.
All three rely on camouflage as part of their survival technique. If they go undetected they can breed quite rapidly and deprive your plant of vital nutrients by sucking out the sap from the leaves.
Spider Mites
These tiny pests tend to live near the base of caladium where they spin small protective webs.
They suck the sap of the plant and often the first time you become aware of them is when you see brown patches with no chlorophyll.
They can easily be removed with a blast of water and kept at bay by wiping the leaves with neem oil every fortnight.
Thrips
Small black or brown oblong insects that only reach two or three millimeters in length, suck sap and cause stripling and yellow patches on leaves. A wipe with insecticidal soap or neem oil should get rid of them very quickly.
Mealybugs
These guys look like your caladium has had a light dusting of flour. In fact, they are tiny insects that produce a white, wool-like protective cover beneath which they suck the sap of your house plants. They too will succumb to being wiped away with neem oil on a soft cloth.
As you will have realized, the most common pests are very fragile and therefore are easy to deal with. The main secret is to examine your plants closely from time to time and give a regular wipe with neem oil should keep them at bay.
Nutrient Deficiency
One factor that can cause your Caladium to start to go off-color and to start to look unhappy is if it lacks nutrients.
Yellowing of caladium leaves can be caused by nutrient deficiencies such as manganese, zinc, or nitrogen, as well as an iron deficiency.
Potting soil can only hold so much of the nutrient that a plant requires for healthy growth, and after that, it is down to us gardeners to keep our plants well-fed.
Solution
I like to feed my Caladiums with a liquid house plant food that is high in Nitrogen which encourages leaf growth.
So, I apply this on a fortnightly basis during the summer but drop right back to once a month in the autumn and overwinter I will not feed my plants at all.
Fertilizer Burn
Caladiums are tubers and these can be damaged if they receive too much fertilizer. A damaged root system reveals itself with wilted and yellowing leaves.
If you know this is not a watering problem then this is something you might need to consider.
Solution
Normally caused by the erroneous belief that the more you feed your plant, the faster it will grow, it can be avoided by only feeding during the summer growth period and ensuring you follow the manufacturer’s instructions.
When you first pot your plant, there will be sufficient nutrients in the potting soil so there will be no need to feed it for at least the first six weeks. After that, follow the schedule above and you should be able to avoid this one.
Low Humidity
This is a problem that many house plant owners face, particularly when growing very leafy house plants.
Caladiums, like many other house plants, are native to the tropics, where natural humidity levels are significantly higher than in our homes. This is a problem that is exacerbated by the use of central heating systems that dry out the air.
Solution
There are a few ways to tackle this problem. One is to purchase a plant air humidifier and raise the humidity near your plant artificially. With Caladiums, I find this isn’t necessary and I prefer to go for more low-tech solutions.
Firstly, I try to cluster plants so that humidity is raised by the combined respiration of the group of plants. Next, I stand my pots on pebble trays.
All these consist of are trays filled with pebbles and water. The pebbles keep the base of the plants clear of the water while the water evaporation increases the humidity for the plant.
Finally, if any of my plants start to look unhappy and I suspect that humidity is the cause of the issue, then I mist them lightly once a day. I do this early in the morning so that the leaves have plenty of time to dry and are not wet overnight.
How to Prevent Yellow Leaves on a Caladium
Here is a quick list for you to use as a reminder from time to time.
- First of all, always check that the roots are not getting waterlogged.
- Adopt a regular approach to checking the soil to ensure that it is neither too dry nor too wet.
- Close examination and occasional wipe downs with neem oil or insecticidal soap should ensure that your Caladium is always pest-free.
- Feed your plant sparingly but regularly.
- Keep humidity levels higher than normal household levels.