Your calathea’s healthy leaves have become discolored seemingly overnight, leaving you scratching your head as to why. Although this change may seem mild, if kept in poor condition, your calathea plant will continue dying. What can you do to save your calathea?
How to save a dying calathea plant? Here’s how to save a dying calathea plant:
- Provide the right lighting conditions (no direct sun!)
- Water only when the soil is halfway dry
- Turn up the humidity to over 50 percent
- Limit temperatures to 64 to 75 degrees Fahrenheit
- Treat pests and plant disease
- Let transplant shock symptoms wear off
As the above pointers suggest, the best way to help an ailing calathea heal is to provide the care it was missing all along. In this guide, I’ll talk extensively about each one of the above care facets, including a step by step process you can follow to hopefully avoid your calathea ever being on the brink of death!
How to Revive a Dying Calathea
Get Your Calathea out of Direct Sun
The prayer plant or calathea hails from the tropical Americas, which can give many indoor gardeners the wrong impression. They assume that between its native home and its bright, vivid foliage that the calathea must appreciate hours spent in the direct sun. Yet this is incorrect.
At first, your calathea will succumb to sunburn, which in houseplants is known as scorch or sunscalding. While you turn bright red after a day of too much sun, plants become brown or yellow. The usually lush leaves of the calathea will dry out as the sun causes all the moisture on the plant’s surface to evaporate.
Without you noticing that’s something wrong, your calathea can become dehydrated. Depending on how often you’re watering it (more on this in just a moment), you could exacerbate the issue as you’re further depriving your calathea of water.
If your calathea leaves are discolored, wilting, or crispy, then you’re overdoing it on the sun.
Immediately move your plant from its spot. From here on out, begin providing some shade and only dappled sun. With dappled sun, a canopy of trees (or something like trees) covers the calathea so it gets bursts of sunlight, but nowhere near the full brunt.
Stop Overwatering or Underwatering
In the last section, I alluded to underwatering, a common mistake that nearly every indoor gardener has made at some point. If you don’t know how to gauge when your plant needs water, then you can assume that because it’s still green, your plant is fine. Yet you don’t want to wait until your plant is begging for hydration to water it.
The far more detrimental mistake to your calathea’s health is overwatering it. If you’re watering the calathea more than twice per week, then it’s safe to say you’re probably overdoing it. The reason that overwatering is such a significant problem is that it can lead to root rot, which is hard to reverse and can kill your calathea plant fast.
A healthy root system receives oxygen from aerated soil and water when you provide it. When one of these two elements overwhelms the other, such as what happens when you overwater, the consequences can be disastrous.
Your calathea can’t breathe as it sits in a pool of water, essentially drowning.
The damage of root rot affects the roots first. New indoor gardeners can miss root rot since their plant will look okay for a few days or weeks. Yet inches and inches into the soil, the once-healthy roots have begun to die. They turn black or brown and their firm texture is replaced by a mushy one.
If you notice a particularly horrid odor around your home or office, that’s your plant’s roots dying. By the time your calathea begins wilting, curling its leaves, or turning brown or yellow at the leaf tips, your plant is in bad shape.
I do have some good news! You might be able to save your overwatered calathea, the keyword being “might”.
8 Steps to Save an Overwatered or Underwatered Calathea
Step 1: Your calathea can’t stay in its waterlogged home anymore, so the first thing you should do is take this opportunity to repot your calathea into a slightly larger pot. Doing this will eliminate having to repot your calathea again any time soon and that will reduce it’s stress in the long run.
Step 2: Holding your calathea by its base, pull it from the pot. Never grab your plant by its leaves, as it’s going through enough trauma right now. When a plant is already struggling, one firm tug on the leaves could cause them to come right out.
Step 3: Carefully lay your calathea on your work surface. Look at its roots. With clean pruning shears, remove all the black or brown roots until all that’s left are the white, healthy roots.
Step 4: Clear as much soil from around your calathea as you can. This is all soaked and shouldn’t be transferred to your plant’s new home.
Step 5: You want the plant to focus its energy on regrowing its roots, not maintaining its foliage. Thus, it doesn’t hurt to trim the foliage.
Please make sure that you disinfect your pruning shears between cutting the roots and trimming the leaves.
You can disinfect by combining water (nine parts) and bleach (one part) in a shallow container and then putting the pruning shears in the bath. Let them sit for 30 to 60 minutes. Try to avoid getting the handles of the shears in the bleach bath, as discoloration can occur. Rinse away any bleach residue when you’re done and let them air-dry.
Step 6: Prepare your calathea’s new pot. This houseplant does well in a mix that’s mostly potting soil (at least 50 percent), then some perlite (around 10 percent), charcoal (up to 20 percent), and orchid bark (also around 20 percent).
This mix is aerated but also maintains soil moisture, which is what the calathea needs. Keep in mind that there’s a difference between soaking wet soil and moist soil.
Make sure your calathea’s new pot has drainage holes.
The pot needs at least one hole in the bottom of the pot at least the size of a nickel or quarter. If not, two or more smaller holes in the bottom of the container should be fine too. JUst make sure that enough water can travel through the holes in the bottom to prevent waterlogging the plant in the future. .
Step 7: Put your calathea in its new pot. Water the soil since it will be completely dry, letting it moisten.
Step 8: Keep a watchful eye on your calathea. If you continue to provide the conditions necessary to its health, then within a couple of months, the roots should have regrown to a healthy degree. Then your plant can focus on regrowing its leaves. Until then, if your calathea looks a little barren, try to be patient. Your plant has been through a lot.
The above measures are not guaranteed to work, I just want to reiterate that. If your calathea’s roots were mostly black with very few healthy roots remaining, then it might be too late to do anything for it.
That said, I always mention on this blog that it’s worth trying to save your plant. At least then, you know that you gave it all you could.
How often should you water your calathea after repotting it?
Do the soil test with your pointer finger. Take a clean finger and put it a few inches deep into the soil. You should water your calathea when the top inch and a half of its soil feels dry.
Although tropical plants don’t always need direct sun, what they tend to require is humidity. Since the calathea is a moisture-loving plant, it makes sense that this species would appreciate moisture not only in its soil, but in the air as well.
To explain humidity means a discussion of relative humidity, something that all indoor environments have to some degree. Relative humidity is how much water vapor is in the air at any one time in a percent over how much water vapor is necessary for saturation to occur when at that temperature.
The average indoor relative humidity is 30 to 50 percent. Yes, that includes your home and office. Most people assume that if they’re not sweating that a room isn’t humid, but that’s just not true.
30 percent relative humidity is not ideal for the calathea. It needs at least 50 percent relative humidity, ideally 60 percent to grow and thrive they way you want.
To introduce more humidity in your home or office, a tabletop humidifier will come in handy. You can mist your calathea, but you’re better off using the humidifier, as it will provide humidity for longer than you have time to squeeze a spray bottle.
Without enough humidity, your calathea leaves can suffer. Any new leaves will be misshapen when they unfurl. Older leaves will sag, curl, or shrivel up.
Houseplants that are in indoor environments that are too dry for their liking will have the edges of their leaves turn brown and become brittle. If these signs sound a lot like underwatering, that’s because the two sets of symptoms are very similar.
For newer indoor gardeners, that can make diagnosing what’s truly wrong with their calathea a bit of a challenge.
Do keep in mind that you can oversaturate your calathea in humidity. Once you’re over 60 percent, and certainly when you get to 70 percent relative humidity or higher, then it’s too hot even for the calathea.
Watch Your Temperatures
Another care mistake that could be killing your calathea is setting the temperature in your home or office too low. Remember, calatheas are tropical plants, so their preferred temperature range is between 65 and 80 degrees.
Damage can occur to the plant should its temperature be higher or lower than that range. Let’s talk about what happens to the calathea when it’s too hot.
It’s okay if your thermostat is a few notches past 80 degrees, even around 85 degrees, but I wouldn’t push it too much further than that. Above 85 degrees can easily stress out your calathea.
If these warm conditions (plus humidity) are what the calathea experiences every day, then turn the thermostat back down a little and your calathea should bounce back.
The far bigger risk is when your plant is exposed to temperatures under 60 degrees. In the winter, the calathea might be able to withstand temperatures of 50 degrees, but no lower than that.
Calathea are especially sensitive to cold given it native tropical environment.
If your calathea is suffering from cold shock, it’s typically not too difficult to tell what’s going on. When a calathea is too cold you’ll be able to tell because its leaves might have red, yellow, or white marks that appear near the leaf veins.
This is more than discoloration, but frost damage. Those parts of the leaves are likely dead, as damage occurred on the cellular level.
Leaves might start dropping from your calathea left and right if it has cold shock, especially if that shock is severe. The leaves that do remain will droop or curl. This is again due to cellular damage that prevents the leaves from maintaining their rigidity.
You don’t necessarily have to leave your calathea outdoors on a cold night for the plant to experience cold shock. Even when the windows are closed, cold drafts like those from an air conditioner can lead to shock symptoms as well. They just won’t be as severe.
When your calathea has cold shock, the best thing you can do is bring it out of the cold environment immediately. Restore the calathea’s proper temperature range and watch how much light it’s receiving as well.
Then, wait and see. If the cold shock wasn’t too severe, your plant should be okay after a few days of exposure to warmer temps.
Treat Pests and Plant Disease
If you saw a group of ants clustering in your dining room, would you ignore the issue? Of course not! So once you spot any signs of pests on your plants, you must give them the same care. Although they don’t look it, pests can be deadly for many houseplants, especially once infestations get serious enough.
There’s one species of pest that’s particularly attracted to the calathea: spider mites. With more than 1,000 species of spider mites, it’s tough to say which has invaded your calathea plant, but all are bad news.
Spider mites will make a home under your calatheas leaves, and there they’ll produce webs and drink sap from until they reach the leaf’s cells.
If your indoor garden is rather varied, you need to take care of your spider mite problem right away. These mites are rather undiscerning about with other houseplant species they’ll munch on, as they’re known to enjoy a few hundred different plants.
Your whole indoor garden could go down in one fell swoop if your spider mite problem becomes serious enough.
Here are the options I recommend for treating pests on your calathea plant as well as any of your other indoor plants.
- Rubbing alcohol: Check your pantries for isopropyl rubbing alcohol that’s at least 70 percent. Apply some alcohol on a cotton swab and then rub the underside of your calathea’s leaves. The spider mites should soon leave.
- Rosemary oil spray: Another liquid that spider mites don’t like is rosemary oil. The extracts in the oil are an insecticide, which is bad news for mites. Make sure you dilute the oil in a quarter of water.
- Apple cider vinegar: Good, ol’ apple cider vinegar can come in handy for your spider mite problem. In a pinch, white vinegar can work as well. In a spray bottle, pour a quart of water. Then add some liquid dish soap (just a few squirts), a tablespoon of baking soda, and 1/4th cup of apple cider vinegar. The mix is too acidic for spider mites to withstand.
- Neem oil: You can buy or make neem oil to send spider mites packing. If you do go the homemade route, here’s the recipe. Take a quart of lukewarm water and add a teaspoon of Castille soap and two teaspoons of neem oil. Then spray.
- Diatomaceous Earth: For an extensive list of the uses of this indoor gardening staple, you should read my article: Why Every Indoor Gardener Needs Diatomaceous Earth
Even with the spider mites gone, fungal and bacterial diseases can kill your calathea if you’re not steadfast. The two main culprits are leaf blight and fusarium wilt, both of which I’ll talk about now.
A common houseplant disease, leaf blight leads to the development of spots across your calathea’s foliage. These spots are ring-like and can become black without your intervention. The affected leaf will soon become further discolored, then curl and die.
Once your calathea has leaf blight, it’s probably a goner since this plant disease is incurable. You can only prevent leaf blight in your other plants to keep them alive. Neem oil can help as a preventative, as can a baking soda mixture. You’d need water (a gallon), liquid dish soap (a teaspoon), vegetable oil (2 ½ tablespoons), and baking soda (a tablespoon).
Do keep in mind that baking soda can burn plant leaves, so use a little of this mixture at a time and see how your calathea reacts. Then apply more.
The fungal disease fusarium wilt can also spell the end for your calathea. Fusarium is a pathogen that lives in soil, invading through the roots. The older leaves of your calathea might first show symptoms, including yellowing and wilting. Then the younger leaves are affected until the whole plant is ill.
To save your calathea if it has fusarium wilt, you need to remove the plant from its pot, solarize or replace its soil, and stop using fertilizer with high quantities of nitrogen.
You might have to apply a chemical treatment such as a fungicide if the disease is serious enough. Please make sure that you disinfect your pruning shears too, as shears can transfer fusarium wilt from one plant to another.
Here’s how to solarize your soil
Take a plastic, translucent tarp and lay out all the soil on it. Leave the tarp outdoors for at least four weeks, six weeks at the most. The weather should be hot and humid to kill fungi and nematodes living within the soil.
Limit Transplant Shock
Handling your calathea should be reserved for certain occasions only, such as when you suspect your plant has root rot or when you need to upgrade its pot. That should only occur about annually, perhaps every other year.
If you’re moving your calathea here, there, and everywhere, then you’re inducing what’s known as transplant stress or shock. You see, plants don’t particularly enjoy being moved from their home. Since it’s avoidable, if you’re strategic about when you transport your houseplants, then you shouldn’t damage them.
Frequent moving will cause symptoms such as leaf discoloration, often yellowing that turns into browning. If you somehow ignore those signs and continue to move your calathea all willy-nilly, it could experience severe transplant shock, which at that point could be deadly.
Treating transplant shock isn’t too difficult. For one, stop moving your plant more than you have to. Once it’s in its home, leave it. Continue feeding and watering your calathea and then wait. Most plants recover from transplant shock in a few days, but for more severe cases, it may take upwards of a week.
Calathea Leaves Turning Brown and Crispy – What to Do
As this article has explained, your calathea leaves can become brown and crispy for a multitude of reasons. Underwatering the plant can dry out the leaves, overwatering the plant saturates them with water, too much sun will burn the leaves, transplant stress can make leaves become brown, and so too can plant pests and diseases. Oh, and let’s not forget that humidity and temperature issues can also lead to leaf discoloration.
What you should do above all else then is identify which of the above causes has led to discoloration in your calathea. If you don’t, then in a few weeks or months, you’ll be faced with brown, crispy, wilted leaves all over again. By then, your calathea won’t have much foliage left.
Should you cut the dead leaves off the calathea?
If they’re completely dead, then yes, these leaves will not grow back. Use disinfected pruning shears to remove the entirety of the dead leaf.
Yet if only the edges of the leaves are crispy and brown, please leave the leaf relatively intact, trimming just the parts that are dying.
Take your time as you do this and try to retain as much as the green, healthy part of the leaves as you can. It’s okay if you trim some green parts, as the leaf should survive, and it will regrow eventually. As always, please disinfect your pruning shears when you’re done!