With their large striking leaves, the Calathea Medallion is definitely a crowd pleaser and is a great way to add a little something special to every room. However, it can be pretty concerning when you discover that your beloved plant is showing signs of distress and unhappiness and you don’t know what’s causing it.
Below you will find an outline of the different causes of the most common problems you might find with a Calathea Medallion so you can not only properly diagnose the issue, but treat it in the right way and stop it from completely taking over your plant.
Top Causes of Brown Calathea Medallion Leaves:
Humidity is one of the key factors to your Calathea Medallion’s health but it’s often forgotten. All Calathea varieties need a higher than average humidity level to thrive and dry air can sometimes cause brown leaf tips or edges. It’s unlikely that humidity issues will turn the entire leaf brown though. Luckily, fixing the issue of dry air can be quite simple. We recommend misting the leaves several times a week as well as investing in a humidifier to give the room a good boost. You can also try things such as pebble trays or moving your Calathea Medallion into the bathroom.
Another factor to consider when diagnosing brown leaves on your Calathea Medallion is consistent underwatering. Whilst your plant won’t turn brown after the occasional missed watering if the issue persists for a few weeks, you will start to see the leaves on your Calathea Medallion turn light brown in colour. Confirm the issue by checking the potting mix and adjust your watering habits accordingly to ensure the root system doesn’t dry out for long periods of time.
It’s really important that you keep your Calathea Medallion away from cold drafts caused by cracks in windows or external doors as well as air conditioning vents that can be quite harmful to plants during summer. Pick up a digital thermometer if you don’t already have one to monitor any temperature fluctuations.
If none of the other issues seem to explain why your Calathea Medallion has developed brown leaves, then it might be sensitivity to tap water that is causing it. If you live in a hard water area, the water you give your plant may be high in fluoride, chlorine and salts and these can build up around the roots of your plant, causing it to develop brown leaves. This process is very slow and will start off as one small brown tip before progressing over the course of a few months to a year. To stop this issue from causing any more brown leaves, use purified water or collected rainwater.
Causes of Yellow Leaves on a Calathea Medallion:
Too much water.
The most common cause of yellow leaves on a Calathea Medallion is overwatering. If the roots are sitting in waterlogged soil for a few weeks at a time, it can lead the roots to rot, starving your plant of needed nutrients, oxygen and ironically, moisture. To check if this is the cause, take your plant out of the pot and inspect the potting mix and root system. If the soil is waterlogged, and the roots are dark in colour and mushy, then this will be the cause of the yellow leaves on your Calathea Medallion.,
Too much intense direct sunlight.
This will usually show up as yellow burnt-like patches rather than entire leaves turning yellow at once. Although these yellow patches are irreversible, moving your Calathea Medallion to a slightly shadier spot will prevent any more from developing across your plant.
A pest infestation.
A more worrying cause of yellow leaves is a pest infestation. You’ll want to inspect your plant immediately and move it away from any other plants (check over those too). If you do spot pests on your Calathea Medallion then this is what is most likely causing the yellow leaves as they slowly suck on the leaves and kill them. Use neem oil daily for a week and cut away the worst affected leaves.
The natural ageing process.
If you can’t seem to pinpoint what is causing your Calathea Medallion to develop yellow leaves, then it might simply be due to natural causes. As your Calathea Medallion (and other houseplants) matures, it will prioritise growing bigger new growth over its oldest leave. These will then turn yellow and fall off your plant. This is nothing for you to worry about as long as the rate of yellowing continues to be slow (one or two every year).
What is Causing my Calathea Medallion to Lose Leaves?
The right temperature is critical when caring for a Calathea Medallion and a drop in temperature can cause them to lose a few leaves. The best way to monitor changes in the temperature is to use a digital thermometer. This will help ensure your Calathea Medallion is not being exposed to any particularly low temperatures.
Plants can get stressed out too and sudden changes in their environment can shock them, causing a few leaves to fall off as a result. Things such as moving your plant, repotting or propagation can cause some level of stress and it can be normal for them to lose a few leaves in the days after. The important thing to note about shock is that it’s temporary and after about a week, if the environment and care is right, your Calathea Medallion shouldn’t be losing any more leaves. Monitor the leaf loss to make sure that something else isn’t causing the leaf drop.
If your Calathea Medallion is only losing a few leaves each year but nothing in the environment is changing that would indicate an issue, then this leaf drop might be natural. As we mentioned above, Calathea Medallion plants can sometimes lose a few of their oldest and smallest leaves in favour of using the energy for new growth. These will usually turn yellow before falling from the plant.
Causes of a Drooping Calathea Medallion:
If your Calathea Medallion has waterlogged soil then this can cause root rot which cuts off nutrients, moisture and oxygen from your plant, causing it to droop down and look quite limp. This is often one of the earlier signs of trouble so this can hopefully mean you have caught the problem early. Inspect the potting mix and replace any soggy soil with fresh dry mix. Moving forward, make sure to allow the water to fully dry out before watering again and this should avoid not only a drooping plant but many other more extreme issues too.
On the other end of the spectrum, a lack of water can also cause your Calathea Medallion to droop down. Your first instinct might be to give your thirsty plant a bucket full of water but this can actually be harmful to your Calathea Medallion if the soil goes from one extreme to the other (see stress paragraphs above). Instead, you want to reintroduce watering by giving your Calathea Medallion a bit of water each day for one full week. As with overwatering, you want to make sure you are monitoring the soil moisture and adjusting your watering habits to prevent your Calathea Medallion from drooping again in future.
Causes of Curling Leaves on a Calathea Medallion:
Calathea Medallions naturally curl their leaves throughout the day which is a trait of the prayer plant family. It can be easy to mistake this curling for an issue but as long as the leaves uncurl each day, this is totally fine and you don’t need to be worried.
If the leaves on your Calathea Medallion do not uncurl or move at all during the day, then we would suspect that something else is wrong, potentially a lack of water. Curling up their leaves is the best way for plants to retain as much moisture as possible. Inspect the soil and give your Calathea Medallion plenty of water over the next few days and you should see the leaves uncurl.
Curling leaves can happen if your Calathea Medallion is being exposed to both hot and cold temperature extremes. Things like drafts and hotspots can really impact your plant’s health and curling leaves are often the first sign of trouble. Use a digital thermometer to check that your room sits within the ideal temperature range for your Calathea Medallion.
Low humidity levels.
Calathea Medallion are lovers of high humidity and can struggle in rooms with dry air. If this is the cause then you must act quickly to prevent it from causing any irreversible problems such as brown leaves on your Calathea Medallion. The best thing to do is buy a humidifier as this will take care of keeping a stable humidity level next to your Calathea Medallion.
Those are the most common issues you might experience when caring for a Calathea Medallion. The number one thing that helps with treating these issues is catching it early in the first place as this makes reviving them a lot easier. Monitor your plants regularly, checking the leaves, stems and roots often to allow you to spot early warning signs.
Check out our Calathea Medallion care guide to find out more about how to care for your plant and prevent any further problems.
Written by Billy Dawson