Growing Calatheas can be challenging even for seasoned indoor gardeners, but getting the fundamentals right makes a huge difference. Proper watering habits are especially vital for these famously thirsty houseplants. This article will give you a thorough grounding in how to water Calatheas, from the types of water you should use to the warning signs of dehydration and overwatering.
Watering Calatheas requires careful attention to their growing medium. Rather than hydrating your plant on a fixed schedule, check the top inch or two of soil in the pot regularly and water when it feels dry. Or, for more precision, insert a probe into the deepest part of the pot to check the conditions at the roots. Always give your Calathea enough water that you can see it draining from the bottom of the pot.
The quality of your water and your soil are also important factors. Rainwater or distilled water are the most appetizing drinks for a Calathea, while a potting mix with good drainage will help you hit the moisture level that your plant prefers. See below for more detail on these core elements of Calathea care, as well as notes on some alternative watering strategies.
How Often Should You Water Your Calathea?
Brand-new Calathea owners often take to the internet in search of a simple answer to the above question and are disappointed when the answers seem to vary wildly. The problem is, there’s no one-size-fits-all watering schedule – especially not for a plant that’s as sensitive to both drought and overwatering as a Calathea.
The varied species that make up the genus Calathea evolved in humid tropical rainforests, and as such, they’re accustomed to soil that remains more or less constantly damp. Calatheas quickly develop signs of strain when the space around their roots dries out completely as their normally luxurious foliage becomes curled, shriveled, and discolored. Repeated drought stress will render the plant more vulnerable to deadly diseases and pests.
At the same time, Calatheas hate the swampy conditions created by overwatering. In fact, too much water can be more deadly than too little. Soggy soil allows bacteria and fungi to breed rapidly and colonize the root system; the resulting illness, known as root rot, is one of the most common killers of houseplants. It can melt your Calathea down to mush in a matter of weeks if it’s not treated quickly.
So you need to keep the soil around the root system damp, but not too damp. We’d love to tell you that you can accomplish that by watering X times a week. Unfortunately, there’s a whole galaxy of other factors that will affect how quickly the soil dries out, including:
- Temperature
- Humidity
- Potting mix particle size
- Container material
- Sunlight levels
- Your Calathea’s growth rate
- The presence or absence of drainage holes
The good news is that you don’t need to try to take all these variables into account and calculate how quickly your Calathea’s potting mix is drying out. All you have to do is check for yourself.
Testing Your Calathea’s Soil
Every few days, poke your finger an inch or two into the soil around your Calathea to see whether it feels damp. Give the plant a drink once this upper layer is dry. There should still be some moisture in the lower levels of the pot, but not so much that you’ll be drowning the roots by adding more.
You can get more precision by using a longer, thinner probe to check the conditions near the roots directly. An unlacquered wooden chopstick works great for this purpose. Insert it down to the base of the pot, let it sit for a few minutes, and then pull it out. If the end is soaked through, the soil is still too wet to water. If the chopstick is only mildly damp or spotted with wet and dry patches, it’s time to hydrate your Calathea.
It’s also possible to use an inexpensive soil moisture meter, though this method isn’t foolproof. What these devices actually measure is the electrical conductivity of the soil. This is a reasonable proxy for the water level, but it can be thrown off by things like built-up mineral salts from fertilizers.
If you’re going to use a
Whatever method you use, you’ll need to experiment a bit to get a feel for how often to check on your plant. As a general rule, Calatheas need more frequent watering during the spring and summer when they’re putting out new growth. And a soil mix that drains faster calls for more frequent checks (more on this later).
How to Water Calatheas
Once you’ve determined that it’s time to give your Calathea some refreshment, you should water thoroughly. That means soaking the soil all the way through until you can see water trickling out from the drainage holes on the underside of the pot. Try to water evenly across the surface so that all of the roots are getting enough to drink, not just those on one side.
Remember all those health-fad articles about how everyone should drink their water at room temperature? I ignored them too, but it’s good advice for your houseplants. Calatheas are vulnerable to temperature shock, so don’t give them water that’s too hot or too cold. Do not water Calatheas by leaving ice cubes to melt in their pot the way some guides recommend for orchids. Your tropical plant won’t thank you for exposing it to near-freezing temperatures!
If you have a drip tray underneath your Calathea’s pot, remember to come back and empty it once the container has stopped draining. You’re practically begging for root rot if you leave your plant sitting in a puddle of water overnight.
Can You Give Calatheas Tap Water?
Even if you’re an expert at finding the right moment to hydrate your Calathea, you can still hurt it by providing the wrong type of water. These plants are known to be quite sensitive to chemicals dissolved in their water or soil. When concentrations are too high, Calatheas will display symptoms that look a lot like fertilizer burn: yellow spotting and crispy brown leaf tips.
Unfortunately, municipal drinking water in many places is too heavy in minerals for Calatheas. And even water that’s relatively “soft” (low in calcium, magnesium, etc.) may contain levels of chlorine and fluoride that your plant can’t tolerate.
The safest choice is to collect rainwater in a barrel or bucket and use that to water your Zebra Plant. Not only is rain low in harmful mineral salts, it typically contains a small amount of the organic nutrients that a Calathea needs to grow healthy new foliage.
Distilled or filtered water is the next best thing. Though it lacks the nutritional value of rainwater, it’s free of impurities that could stunt your plant’s growth. You can add some organic or synthetic fertilizer if your plant needs a boost to its diet.
Signs of Underwatering in Calatheas
Let’s say it’s been a while since you gave your Peacock Plant a drink, and you’re worried that it might be getting dehydrated. Here are some key indicators to watch out for:
- Dry Soil. The best way to spot a thirsty plant is by looking for thirsty soil. Most of the other signs on this list can also be caused by things like overwatering or poor humidity. But if they’re paired with dry, compacted soil that’s peeling back from the sides of the pot, underwatering is the likely culprit.
- Drooping Leaves and Stems. When the cells of your Calathea don’t contain enough moisture, they’ll get slack and flabby. As a result, the plant can’t stay as rigid; it starts to droop and slump like a sulky teenager. Note that these plants naturally spread their leaves down and out during the day and then lift them at night; get to know its habits so that you can tell when it’s wilting and when it’s simply undergoing its daily routine.
- Curling Leaf Edges. If the margins of your Calathea’s leaves begin to curl inward like the two halves of a Torah scroll, it means they’re lacking in moisture. This can happen if either the air or the soil is too dry, so check for both low humidity and underwatering.
- Yellowing or Browning Foliage. This one is a bit ambiguous, as it can be a sign of overwatering as well as underwatering. Again, test the soil to see if you’ve let the plant dry out before you soak it.
Signs of Overwatering in Calatheas
What warning signs can you expect if you’re overdoing it with your plant’s hydration? In many cases, they’ll be the same symptoms that you’d see in an underwatered plant. That’s because underwatering hampers the roots by denying them oxygen and rendering them vulnerable to infection. It’s possible to give your Calathea so much water that it starts dying of thirst!
That said, here’s what to look out for:
- Soggy Soil. Pay attention to how quickly your Calathea’s potting mix dries out; if it still feels wet 5 or 6 days after watering, that’s a danger sign. And if your plant seems dehydrated when the soil is still moist, it probably means that the roots are stressed out. Hold off on watering for a little while to give them some breathing room.
- Yellowing Foliage. Again, discolored leaves can also indicate thirst, but in an overwatered plant, they’ll often feel fleshy rather than dry and crispy. The yellowing will also usually start with the lower leaves and work its way upward in cases of overwatering.
- Browning Leaf Tips. This can indicate stress from tap water or fertilizer, but it can also point to root rot.
- Musty or Foul-Smelling Soil. This is a definite danger sign. It almost always means that root rot has set in and will need to be addressed immediately.
Rescuing a Calathea From Root Rot
When you suspect that your Calathea has begun to develop root rot, take action right away. Part of what makes this disease so insidious is that it spreads below the soil first, meaning that the damage can be quite extensive before you start seeing problems with your plant’s foliage. You’ll need to act fast to save your plant.
Start by taking your Calathea out of its pot to inspect the roots directly. You may need to gently brush or rinse the potting mix out of the root mass to get a clear view.
You’re looking for anything that seems to have the wrong color or texture. Healthy Calathea roots are pale and firm, while rotting ones look brown, grey, or black. They’ll also feel soft and slimy to the touch. Snip away any roots that look or feel wrong using a sharp set of pruning scissors. Sanitize the blades before and after each cut by wiping them down with a rag dipped in a cleaning solution – good options include household bleach (diluted to 10% strength) or isopropyl alcohol.
The rule here is to cut first and ask questions later. Remove every bit of root tissue that seems even a little mushy. Any rot you miss will start spreading again as soon as your Calathea is back in the soil. If you have to take off more than a third of the plant’s roots, trim away a similar proportion of the foliage, starting with the least healthy-looking leaves.
Then replant your Calathea in fresh potting mix. If you reuse the old container, wash it thoroughly and wipe it down with the disinfectant you used on the shears. You can also dunk the remaining roots in a watered-down solution of hydrogen peroxide – about one tablespoon per cup of water – to kill off any microorganisms clinging to them.
Soil Mix and Watering For Calatheas
You’re probably already beginning to grasp how important soil quality is for getting your watering routine right. So let’s talk about what kind of soil will help your Calathea get the right amount of hydration.
When selecting a potting mix for your Calathea, your goal is to strike a balance between drainage and moisture retention. You want the soil to quickly shed any excess water to avoid the clingy muck that causes rot. At the same time, you want the pot to hold onto enough moisture that the plant’s roots don’t get too dry between waterings.
You can achieve this by using a base of coarse elements like pumice and pine bark to create plenty of air pockets, along with some airy and absorbent organic material that will soak up some water without impeding drainage too much. Try the following recipe:
- 40% pine bark
- 30% coarse perlite
- 20% coconut coir
- 10% worm castings
If you don’t want to go to the trouble of creating a custom blend, you can usually get decent results with an off-the-shelf African Violet potting mix. Bear in mind that it likely won’t drain as well as the coarser mix described above.
Interested in a more detailed breakdown of Calathea soil requirements? We have an article devoted to the topic here.
Humidity and Hydration For Calatheas
As we noted earlier, a lack of humidity can often cause the same kinds of problems in Calatheas as underwatering. Zebra Plants and their cousins are adapted to the moist air of the tropics. Most homes in temperate climates aren’t that humid for most of the year.
You’ll need to create a zone of higher humidity around your Calathea to keep it from crisping up. This will also make the soil dry out a bit more slowly so that your plant will be less likely to suffer drought stress between waterings.
Here are a few tricks that can help you pump up the local humidity – try different combinations and see what works best for your home and your plant!
- Cluster your plants together. If you have multiple Calatheas, or houseplants like aroids or ferns with similar moisture requirements, you can group them in the same area to create a miniature jungle. Plants are constantly releasing water vapor from their leaves, which can be quite helpful for their neighbors.
- Keep your Calathea in the bathroom or kitchen. The two most humid rooms in your house are often good locations for plants that crave moisture. This will work better if the space in question receives a good amount of bright indirect light.
- Mist the foliage. Spritzing your plant with a spray bottle at least once a day will help simulate the effects of high humidity. Use room-temperature water and apply the finest droplet setting possible.
- Keep the plant on a humidity tray. Place some smooth pebbles in a shallow dish or tray, add some water, and then set your Calathea’s pot on top of the rocks. Refresh the water as it evaporates, but don’t fill it so high that it touches the bottom of the container. If the pot is in contact with the water, you’re risking root rot.
- Use a humidifier. If the manual methods described above aren’t getting the job done, you may need to try a technological solution. A warm mist humidifier will also help with the temperature issues that can plague Calatheas in the winter.
Can You Bottom Water Calatheas?
One popular approach to watering houseplants works from the bottom up, submerging the pot’s base so that the moisture wicks up through the soil using the natural capillary action of water. This approach has both upsides and downsides.
Advantages of bottom watering:
- Evenly saturates the soil, avoiding the dry pockets that can occur with top-down watering
- Reduces risk of fungal infections from wet leaves or crown
- Helps the soil stay aerated since it won’t be compacted by water trickling through it
Disadvantages of bottom watering:
- Doesn’t wash salts from fertilizer and tap water out of the soil
- Requires monitoring the plant until it’s saturated, which could take anywhere from 10 minutes to an hour
- If you forget the plant and leave it in the water tray, you could wind up with root rot
So is bottom watering right for Calatheas? The answer will have a lot to do with your individual setup and preferences. Bottom watering is both less effective and less necessary with better-draining soils; with a more porous mix, less water will be pulled up, and there’s less risk of uneven soil saturation. And Calatheas don’t mind wet leaves the way fuzzy-leafed plants like African Violets do.
Those using something closer to ordinary potting soil may find that bottom watering works well. Those using a coarser mix like the homemade blend we described above will probably be better off watering from the top.
To bottom water your plant, set its container inside a larger tray and fill the bigger container with water until it’s higher than the sides of your Calathea’s pot. Then wait. Check on it every few minutes to see if the water level in the reservoir is continuing to go down. Once it stops receding, the soil around your Calathea is fully saturated, and you can take it out of the tray.
If you choose to bottom water your Calathea, you should still flush the pot from the top down once every month or two to rinse out accumulated mineral salts.
Can You Grow Calatheas Hydroponically?
Some houseplant owners get around the watering issue by raising their green companions hydroponically – that is, rooted only in water, with no potting mix at all.
It’s not as crazy as it sounds. Many plants are capable of developing specialized roots that let them absorb exactly as much water as they need. Going entirely aquatic presents less risk of root rot than a soil that alternates between partly dry and severely waterlogged.
Along with removing the risk of both overwatering and underwatering, a hydroponic setup improves humidity, since the water below the plant is constantly evaporating up toward the leaves. Hydroponic growing also makes it easier to monitor the plant’s health – you can keep it in a glass jar, letting you observe the roots directly and look for signs of infection.
Besides, there’s something that just plain looks cool about a plant’s twining roots floating in a clear vase. Many owners choose this method for the aesthetic value alone.
Will this work for your Calathea, though? The answer is…mmmaaaybe.
Calatheas can sprout water roots, and they can survive in a hydroponic setup for a while. But they won’t grow nearly as quickly, and in the long run, they’re likely to be less healthy than plants rooted in a well-aerated potting mix. Try as we might, we couldn’t find any reports of Calathea owners keeping their plants in water for more than a few weeks.
Should you decide to try the experiment, remember that you’ll have to supply all of your Calathea’s nutritional needs with liquid fertilizer. You’ll also need to control the pH yourself. You should replace the water and clean the container every 2-3 weeks (or more frequently if it seems to be getting dirty more quickly).
Semi-Hydro For Calatheas
Semi-hydroponic growing offers many of the benefits of full hydro but presents a bit less difficulty. Instead of completely filling the container with water, you provide a small reservoir in the base of the jar; then, you fill the rest of the space with an absorbent medium that can wick moisture up to your plant. The most common substrate for semi-hydro is LECA, which stands for lightweight expanded clay aggregate – basically, little spheres of porous baked clay.
In contrast to the near-total lack of information on growing Calatheas in full hydro, there are plenty of experienced houseplant owners who have tried raising them semi-hydroponically. The consensus is that it can work quite well, but it’s hard for Calatheas to survive the transition from ordinary potting mix to LECA.
These finicky plants tend to struggle with transplant shock under ordinary conditions, and semi-hydro presents an extra challenge: your Calathea needs to grow water roots to adapt to the soilless medium. To make the move easier, add an intermediate full-hydro-phase for 3-5 weeks. This will give the plant’s aquatic roots time to grow to a decent size before they need to grip anything.
When it’s time to transplant, wash and sanitize your LECA spheres, then water them until they’ve absorbed as much as they can. Add them gently to the pot, then fill it roughly ¼-full of distilled water.
Remember that growing Calatheas takes a fair amount of skill even in ordinary conditions. If you’ve never tried hydroponics before, we don’t recommend starting with one of the plant world’s most infamous divas.
If you’d like to learn more about LECA and how to use it for Calatheas and other houseplants, read this article.
Final Thoughts
Don’t get discouraged if your Calathea seems to be constantly shriveling up and threatening to die of thirst. They’re known for flying into conniptions when any of their growing conditions are less than perfect.
Just be patient, provide a healthy potting mix, and pay careful attention to how your plant and its soil respond to watering. In time you’ll master the hydration habits you’ll need to keep your Calathea in excellent health.