There are a lot of factors that can make Calathea crimson stop growing. These are some possible reasons that you need to know. Please check everything out before diagnosing your plant. It is really important to consider the full range of possibilities before trying to solve the problem as some of these problems can look really similar to one another.
Reason 1: Getting too much water
One of the most common things that prevent Calathea crimson from growing is watering issues. It is usually about getting too much water instead of getting neglected. The roots can be smoother if the soil is in wet condition for too long. Not only that, it can also cause the oxygen to be cut off when it is really needed. Root rot can happen if this kind of issue persists.
Check out the soil. If it is still moist even after days getting watered, do not water it again right away. It is better for you to test the potting mix by using your finger before giving it water again. If the top two inches are still damp, you are encouraged to wait for another day or two.
Aside from preventing the Calathea crimson from growing, overwatering can also cause extra symptoms such as yellowing foliage and browning leaf tips. In the worst case, there might be squishy stems and swampy smells. If there are such signs, it means there is a severe case of root rot.
If you think there is root rot, you can take the plant out of the pot and then inspect the root system. Please do it carefully. Next, get rid of any roots that are mushy, gray, or black. Do not forget to disinfect the pruning scissors with rubbing alcohol or a 10% bleach solution between cuts.
Reason 2: Getting to little water
Just like overwatering, underwater is also bad. Water is needed for Calathea crimson to grow well. If it is dehydrated, there is no way for it to grow. Instead of growing, its leaves and stems will droop and sag. Besides, the foliage will also curl inward at the edges and develop brown patches of dead tissue.
If you think that your plant is no longer growing and the soil looks dry, water it more frequently. Keep in mind that the surface of the potting mix should not remain damp between waterings. However, make sure to also avoid the soil to dry out completely. Use a wooden chopstick to check if it needs water. If the tip is only slightly moist, water it again.
If you really water it regularly, it seems like there is an issue with the quantity and not frequency. Remember to water it thoroughly until at least 20% of what you put in. This underwatering issue can be solved easily if it gets enough water. While it is true that the leaves that have already dried out will stay that way, the plant will start putting out new foliage again.
Reason 3: There is no enough light
Sunlight is as important as water for Calathea crimson. It is the one that powers the growth of the plant. However, putting it in the direct sun is not recommended as it can burn the plant. Just like putting it under the right sun, putting it in a place that is far too dim is also not recommended because it will produce little or no new growth. Even if it produces new stems, they will be tall and spindly and the leaves will be overly large, floppy, darken, and losing their vibrant contrasting patterns.
The best light for Calathea crimson is bright, indirect light. One of the best options is a sunny south facing room. It is best as long as you keep the plant 4 to 6 feet back from the nearest window. If there is no way for you to do that, you can hang some sheer curtains to take the edge off the rays of the sun. If there is no ideal place in your home for this plant, you might want to consider using a decent grow lamp.
Reason 4: The humidity is low
As Calatheas crimson is originally from the misty jungles of Central and South America, they love air that is rich in moisture. Its growth can be held or stopped if the humidity is lacking. You can tell that the humidity is low if you see slow growth, curling leaves, and crispy edges and tips. Even though you give enough water, the water is wicked by the dry air out of the leaves too quickly. Please do your best to keep the humidity around the plant above 60%. One of the most recommended methods is to group the plans close to each other. Do it along with any other tropical plants in your place. It is not a right to let the leaves touch. Apart from that, another way that you can do is to place the plant on a pebble tray to keep the pot elevated above the surface to prevent root rot at the, while the water evaporates and helps to bump up the humidity.
A humidifier is the best tool to fix the dry air. To make Calatheas crimson grow well, place a portable humidifier close to the plant.
Reason 5: Lacks of nutrient
There is no way for Calathea crimson to die from lack of fertilizer. While nutrients are important, giving too much of it is not good. If you want your plant to grow well, you are suggested to use a liquid formula with a balanced ratio of nitrogen, phosphorus, and potassium (NPK). Aside from that, you can also use an organic fertilizer with a 3:1:2 ratio. Feel free to use one of them. Please dilute it to 1/8 or ¼ of the strength recommended on the packaging and use it to water the plant once every month. If it looks like the plant is lacking in nutrition, increase it gradually.