Calathea is another genus within the prayer plant family, Marantaceae. They’re commonly called prayer plants, just like the genus Maranta that was covered in a previous post, but they also go by their genus name, Calathea. The genus Calathea contains about 60 species. There were previously about 200 species that were formerly assigned to this genus, but were reclassified to the genus Geoppertia. Like their relatives in the Maranta genus, calathea have colorful ornamental leaves and are pet safe. They often have purple on the underside of their leaves which can help to distinguish them from their relatives with the same name. They also share similar care, though they can be a bit more challenging than maranta because they do not thrive on neglect and require that you mimic their tropical environment. With this care sheet, they will be able to thrive in your care if the conditions are met!

Light

            In the wild, these are plants that are native to the understory of tropical rainforests. This means they experience dappled light or shade. Be sure to keep the plant in indirect light. Direct light for extended periods of time will cause the leaves to burn. Sunburn will not heal and will last for the life of the leaf. Bright indirect light will cause the plant to thrive and grow more quickly than if in medium to low light conditions, though this genus can tolerate all three levels of indirect light. If you notice your plant’s leaves are all facing the same direction, this is an indication that the plant does not have enough light. Either increasing the light with a grow light or rotating your plant will improve its appearance and growth. If adding a grow light, be sure to read the directions that come with it. They carry the same risks of burns as the sun, but each light is different and has different recommendations. Typically the light should be mounted 12-24 inches above the tallest point of the plant. Using the light on a lower setting may help prevent burns.

Water

            Calathea should be kept in consistently moist soils, but not soggy. Waterlogged soil will still cause root rot. Water when the soil just begins to dry on the top inch and do not allow the soil to dry completely.  If the leaves begin to curl in on themselves, the soil is too dry. When you water, be sure to saturate the soil completely. This may sound like creating waterlogged soil, but overwatering is not the quantity of water added, but the frequency. No matter if you are watering from the top or the bottom, the soil should be saturated completely. This means if from watering from the top, adding water until the excess drains from the holes in the bottom of the pot. If watering from the bottom, be sure the tray used to hold the water has enough to saturate the entire pot of soil. This may mean that you need to add water halfway through the soaking process. Allow the plant to soak until the soil surface is moist. This could take minutes or hours, depending on the size of the pot. Always check the soil before you water. This is the most common reason that root rot occurs. Plants do not function on a schedule like watering every Sunday, for example. If the soil is allowed to dry to the plant’s preferred level, in this case only allowing the top inch to begin drying, the plants will succeed.

Soil

            The soils that calathea grow in in the wild have a high organic content. The “dirt” portion of potting soil. Because of this, potting soil you get off the shelf at your local garden centers will work perfectly without amendments. Fertilizing your plants regularly will help to promote beautiful growth. How often is appropriate to fertilize depends on what type of fertilizer you use. Slow-release fertilizers, liquid fertilizers, and soluble fertilizers all have different suggested application methods and frequencies. It is best to follow the directions on the label. Sometimes, calathea may bloom. There is a rumor out there that blooms mean your plant is in decline. This is the opposite of true! Flowers are a sign that your plant is getting enough light and nutrients. The plant will funnel its energy into the flowers, so  if you would prefer, you can trim them off to redirect the energy back into the foliage of the plant.

Common Problems

            Calathea don’t often suffer from diseases, most of the common problems they face are environmental or pest related. Here are a few of the most common problems and how to fix them.

Browning Leaf Edges

            Browning along the edges of the leaves are a common sign among humidity loving plants that the air is just too dry. This may be a simple solution of moving the plant to a room with higher humidity like the kitchen or bathroom. A humidifier may be needed in order to fully resolve the issue. Brown portions of the leaves are dead and will not heal, but will not cause additional harm to the plant to be left on. If you prefer to remove the brown portions, leave a sliver of brown on the leaf to avoid causing unnecessary wounds that will still scab over brown.

Large Brown Spots on Leaves

            Large brown sections of the leaves that are not concentrated on any specific portion of the leaf are a sign of a fungal infection. Treating with a fungicide is the best move if you find this to be the case. Again, these portions will not heal and will remain for the life of the leaf. While removing the affected leaf or leaves may not resolve the infection, it is still good practice to do so to assist to slow the spread of infection. Allowing water to sit on the foliage and too little ventilation are often the main causes of fungal infections of this nature.

Mealybugs

                        Mealybugs are a white, sap-sucking insect that produces the honeydew mentioned above. They often hide on the underside of leaves and in tight crevices of new growth. They are easily treated with pesticides, an alcohol mixture, or beneficial insects. For more information on how to identify and treat mealybugs, check out the blog post titled Mealybugs and How to Deal with Them.

Spider Mites

Spider mites are tiny, spin webs, and feed on the sap of many houseplants. Often, you will find their webs or see the damage they cause before you see the spider mites themselves. Washing the leaves and increasing humidity will help to decrease and eliminate the population. Insecticidal soap and systemic pesticides may also be needed if the infestation is severe. For more information about treatment and identification, please reference the article titled Spider Mites and How to Deal with Them.

Scale

            Scale are another type of sap sucking insect, similar to mealybugs. They come with the same risks of the spread of disease and sooty mildew, but, unfortunately, cannot be resolved exactly the same way. The hard armor this type of scale comes with which make them appear as brown bumps on the stems and leaves of the plant protect them from simple solutions such as rubbing alcohol. It is best to physically remove the insects from the plant and crush them, in combination with either pesticides or beneficial insects. Be sure to follow the label on the pesticide bottle, as they are not to be applied in any other way. Not following the directions can affect either the safety or the effectiveness of the product. Aphytis melinus and Lindorus lophanthae are two of the most used beneficial insects used to control scale.

 

            While calathea may not be the easiest houseplant out there, once the conditions are met, this is an incredibly rewarding houseplant to care for and is easy once the conditions are met! As always, if you have any plants that you are concerned about, please don’t hesitate to reach out! Send a photo or several as well as how you have been caring for it to cedarbridgebotanicals@gmail.com.

Happy Growing!

<3 Gina