Calathea is a genus of plants native to the Brazilian tropical rainforests, and has gained popularity as a houseplant in recent years. It has dark green, oval leaves run through with unique and eye-catching veins and stripes that come in several different colors, depending on the species.
If you want to grow a calathea, you will need to do some research regarding its preferred living conditions. These plants can be quite finicky about sudden changes in their surroundings, but once you have mastered the correct combination of conditions, they should grow quickly and have few problems.
In the mainland United States, it is better to grow your calathea indoors, but if you live in the southern states or Hawaii, you can easily grow them outdoors.
When it comes to the problems that calathea owners encounter, one of the most common is brown leaf tips. This discoloration can be due to several factors, but the most probable ones are too much fertilizer, poor water quality, underwatering, low humidity, too much sunlight, and cold temperatures.
In this article, we will discuss all of these causes of leaf tip browning, as well as what you can do to remedy them. Read on to learn more!
Why does my calathea have brown tips?
Too much fertilizer
Overfertilizing your calathea can cause browning of its leaf tips. This is because too much fertilizer results in a buildup of mineral salts in the soil, which causes soil toxicity and root burn.
If your plant was growing well for the first few months, and the brown tips only started appearing after you began regularly fertilizing it, then overfertilization is almost certainly the cause of your problem.
Calatheas can grow quickly, even if they are not fertilized. Unfortunately, some people still believe that all plants need to be fertilized to grow faster and denser, but this is really not true across the board. If your initial potting mix is already rich in organic components, you can forgo fertilizer altogether.
An overfertilized calathea with considerable mineral salt buildup in the soil will present with droopy leaves that have brown tips.
If you suspect that the brown tips on your plant’s leaves are caused by overfertilization, stop fertilizing it immediately.
If you have spotted the browning in its early stages, you can get rid of the salt buildup in the soil by decreasing the number of days between waterings to slowly flush out the excess fertilizer from the soil.
If the damage to the leaves is more significant, it means that the mineral salts have been accumulating for some time. In that case, you will need to flush the soil properly as soon as possible.
To do this, place the plant in a sink or shower and start pouring water over the soil. The volume of water that needs to pass through the soil is equal to five times the volume of the plant’s pot. After pouring the water, leave the plant in the sink for 30 minutes, and then repeat the same step three more times, leaving 30 minutes between each cycle.
After the fourth cycle, place the plant on a drying rack and let the excess water drip from the pot’s drainage holes for a few hours before placing the plant back in its usual spot.
If you really want to fertilize your calathea, do so only during the spring and summer months, when the plant is actively growing. To decrease the risk of overfertilization, dilute the fertilizer to half the dosage strength stated in the package instructions.
Do not fertilize your plant in the fall and winter, because its growth slows significantly during this time and any nutrients you add to the soil will not be consumed. Instead, they will add to the detrimental buildup of mineral salts in the soil.
It is also a good idea to make a habit of flushing the soil in your calathea’s pot every six months, as a precautionary measure.
Poor water quality
If you are giving your houseplants tap water, this can be a cause of their browning leaf tips.
Tap water in most cities contains impurities that, while not harmful to humans, can damage your plants. Chlorine and fluoride are two of the most common impurities present in tap water.
If you have been giving your calathea tap water from the beginning and have not noticed any problems until now, it can be because these elements accumulate in the soil over a long period of time, so you might not see the negative effects until after months, or even years.
Coupled with the mineral salt buildup from fertilizers, the impurities from tap water can damage the roots of your plant to the point that it also affects the leaves; hence the brown tips.
To fix browning leaf tips caused by tap water, switch to distilled water, filtered water or rainwater instead. Just like fixing an overfertilized calathea, water the plant from above with distilled, filtered or rainwater a little more frequently than normal, just until you have flushed out the chlorine, fluoride and other impurities that have built up in the soil.
Even once you no longer use tap water on your calathea, repot the plant every three to four years, during its growing season. It will be all the better for having its nutritional needs replenished with fresh soil.
Underwatering
Neglecting your plant’s watering needs causes dehydration and drought stress. There are several ways that underwatering can come about, as discussed below:
- A potting mix that is too loose and does not retain sufficient moisture will allow the soil to dry out too quickly. Because the calathea is a tropical plant, it appreciates moist soil and will become thirsty between waterings in these soil conditions.
- If the roots of your calathea are severely damaged by root rot, or if they are injured from you digging or tilling too close to them, the remaining healthy roots might not be enough to supply the entire plant with water and nutrients. This also leaves the plant underwatered, which can manifest as browning leaf tips.
- Likewise, if your calathea is rootbound, the roots will be so constricted that it will be difficult for water to reach the lower parts of the pot. If only the roots close to the top can get water, the bottom roots will dry out and become dehydrated.
- Still, the most likely cause of underwatering is neglecting to water your plant when you need to. You might not even be aware that you are underwatering it. For example, you may be watering it every five days during the winter and the plant is doing well, but then you forget to adjust your watering schedule when summer comes around. In the spring and summer, the soil will dry out faster, so you will naturally have to water the plant more often.
An underwatered calathea will present with dry, curling, wilted leaves, potting mix that is so dry that it crumbles in your hands, and browning of the leaf tips or even the entire leaf.
If you were able to spot the early signs of underwatering, you can just water the plant’s soil generously from above. Soak it until you can see water flowing through the drainage holes at the bottom of the pot, thus ensuring that all the roots have access to water.
If your plant has been deprived of water for too long, however, the soil can be so dry and compact that it has become hydrophobic, or water repellant. In this case, no matter how much water you pour over the soil, it will never seep in, instead just spilling over the edge of the pot or down the insides.
If this is the case, bottom-watering is your next step. To do this, place the pot in a shallow basin filled with about three inches of room-temperature water and leave it there for 10 to 15 minutes. The thirsty roots and soil will absorb the water through the drainage holes at the bottom of the pot.
After 10 to 15 minutes, remove the pot and place it on a drying rack to let the excess water drain for a few hours before returning the plant to its usual spot.
Repeat this bottom-watering technique three to four more times, each time allowing the top two inches of soil in the pot to dry out first. After the fourth cycle, you should notice signs of recovery in your calathea and can revert to regular watering.
To avoid underwatering your plant in the future, make sure you use a potting mix that retains moisture well, while still allowing excess water to drain easily. A mixture of regular potting soil and well-draining potting mix is a good start.
If your calathea is rootbound, repot it in a larger container, or reuse the same container but prune away a significant portion of the root ball.
If a large portion of the roots have been injured or damaged, you can help them recover by removing one-quarter of the plant’s foliage so that the roots do not have to work as hard to provide for so much foliage.
Low humidity
If you keep this tropical plant in an environment with low humidity, the lack of moisture in the atmosphere can cause its leaf tips to turn brown.
When growing a calathea in your home, your aim should be to simulate the growing conditions it would have in its natural habitat. Calatheas love high humidity, so if you live in a dry climate, there is a good chance that its leaves will dry out too quickly; hence the browning tips.
The longer the plant is kept in these low humidity conditions, the drier the leaves will become, eventually curling and wilting. This can even kill the plant, eventually.
If you think your calathea is drying out from low humidity, there are measures you can take to keep it happy.
First, you could place the plant in the bathroom or kitchen, because these are the most humid rooms in any house.
You can also place the plant’s pot on top of a tray filled with pebbles and water. As the water evaporates, it will moisten the air around the plant.
If you have other tropical houseplants that enjoy humid conditions, you can group them together with your calathea so that they all create a microclimate around each other.
Finally, if you have the means, you can take the easy route of purchasing a humidifier. This will automatically regulate the humidity levels in the room where you keep your plant, so that you do not have to worry about it drying out.
Too much sunlight
Calatheas, like most tropical plants, have evolved to grow best under bright, indirect light. When these plants are in their natural habitat, they grow close to the ground and the only light that reaches them is the dappled light that filters through the tree canopy.
If you place your calathea under direct sunlight for too many hours a day, the leaves will scorch and burn, initially presenting with yellowing tips and turning brown over time.
Your plant can get sunburned even indoors, so do not be complacent. If you place it near a south- or west-facing window, it is likely to suffer sun damage because these windows get full afternoon sun, which is when the light is at its hottest and most harmful.
If the leaf tips of your calathea are browning from too much sunlight, transfer it to a shadier spot immediately. If you keep it outdoors, choose a shady spot under a large tree or on the eastern side of your house.
If your calathea is an indoor plant, place it next to a north- or east-facing window, because these windows let in bright, gentle morning sunlight while remaining in the shade the whole afternoon.
If the only windows in your home let in very harsh light, you can still place the plant near them, but it would be a good idea to hang a sheer curtain over the window to diffuse the light.
Cold temperatures
Calatheas like warm temperatures similar to those of their tropical habitat. Keep the temperature between 70 and 85 degrees Fahrenheit in the room where your plant is kept.
Calatheas are very sensitive to the cold and will get seriously damaged if exposed to temperatures of 55 degrees Fahrenheit or lower for too long.
Air-conditioning vents, cold drafts and outdoor frost can all cause a sudden temperature drop around the plant, and the stress and cold damage will manifest as browning leaf tips and edges.
The only way to prevent cold temperatures from browning your plant’s leaf tips is by keeping the plant’s preferred temperature constant, moving it away from air-conditioning vents and drafty doors or windows, and remembering to bring it indoors before the winter frost.
Conclusion
Calathea is a genus of tropical houseplants native to Brazil. It has dark green, oval leaves run through with unique stripes and veins that come in a variety of colors depending on the species.
The calathea is quite sensitive to any growing conditions that are drastically different from its natural habitat, but if you manage to simulate the environment of a Brazilian tropical rainforest, your plant will thrive.
One of the most common problems encountered by calathea owners is the browning of their plants’ leaf tips. The possible causes of this discoloration are too much fertilizer, poor water quality, incorrect watering, low humidity, too much sunlight, and cold temperatures.
Identifying the exact cause of the browning leaf tips is the first and most important step in your calathea’s recovery.
Image: istockphoto.com / Firn