Question
Sick Calethea
I have a Calathea Second Chance Plant that was growing beautifully this summer. It would spread out with its leaves in the day and at dawn, it would fold up like it was sleeping.
All of a sudden it did not fold up. Then the leaves started turning brown on the edges and curl, then they started to have brown and black blotches on the leaves with yellow tint.
What happened? Can it be saved?
Please help!!!
AnswerHi Secunda,
It is not unusual for Marantas (Calatheas are members of the Maranta family which also includes Prayer Plants, Stromanthe and Ctenanthe) to stop folding up at night (Plant biologists call these daily cycles circadian rhythms) as one of the first signs that the plant is stressed and/or has a problem.
There are several things that could be causing problems with this plant. From what I can see in the picture you sent, the main problem at the top of my list is a fungal leaf infection. The large brown leaf spots with dark brown/black spots (these black spots are called 'fruiting centers') and yellow halos are typical fungal leaf spots. The leaves that are affected by the fungal spots will never heal and will only infect other leaves. You will need to remove the leaves with the fungal spots. However if more than 1/3 of the plant's leaves are affected then you will have to only remove the most damaged leaves and try to treat the rest (you should never remove more than 1/3 of a plant's leaves). The less damaged, treated leaves can be removed later after the plant produces more new leaves (for every new leaf that sprouts and opens, remove a damaged leaf). Spray the less damaged leaves with a commercial anti-fungal spray. I would recommend using Consan 20, you can find it in most nurseries and some garden centers. If you can not find it, then another commercial anti-fungal plant spray should be okay.
Spray the entire plant, not just leaves with fungal spots on them, at least once a week until you remove the last leaf with fungal spots. It might be a good idea to spray the plant once more after there are no longer any leaves with fungal spots. This should kill any fungal spores that may be on leaves that do not yet have fungal leaf spots. Just because a leaf does not have fungal leaf spots does not mean that there are not fungal spores on the leaf and that it will not develop fungal spots in the near future. Spraying the plant with an anti-fungal spray once a week should force the fungus into a dormant state and prevent the 'fruiting centers' from producing spores which spread the fungal infection to other leaves. However, it is always possible that spores can be produced and spread, even with weekly treatments.
Fungus need moisture to be active and produce spores, so keep the leaves dry at all times.
I would recommend that you even start watering the plant from the bottom instead of the top. Pour the water into the drainage tray. The soil will draw up the water through the drainage holes at the bottom of the pot. Refill the drainage tray until the soil no longer draws up the water. Empty the drainage tray after about 30 minutes so that the plant is not allowed to sit in water, which will cause the soil to stay too wet and can cause root rot.
Stop misting the plant if you regularly mist the Calathea to raise humidity.
To prevent additional stress on the plant, be especially careful to make sure that the plant gets proper care (such as proper light, watering, ect...).
Check the plant carefully for any sign of insects or mites. If insects or mites are found on the plant, deal with them as quickly as possible to prevent additional damage to the plant. Also if you find signs of insects/mites you can treat the plant for both the insects/mites and the fungal leaf spots by using a '3 in 1' spray. These can be found in most stores. Most '3 in 1 sprays are made with Neem oil. Neem oil is an insecticide with anti-fungal benefits and is safe to use on most plants. Neem oil may not be as effective as a anti-fungal spray as Consan 20 or other anti-fungal sprays.
Another problem I noticed in the picture are brown leaf tips and brown leaf edges. This is most commonly caused by water quality and low humidity.
Like a lot of plants, Calatheas are sensitive to the fluoride, chlorine and mineral deposits found in most tap water. Water softeners contain a lot of salts that can also harm Calatheas. Using distilled water to water your Calathea will help prevent browning leaf tips plus many of the other problems that can be caused by tap water.
After you are sure the fungal leaf infection is gone, raise the humidity around the Calathea. One way to raise the humidity around a plant place the plant on a tray of pebbles filled halfway with water. Be sure that the bottom of the pot is not sitting in the water.
Another way to raise the humidity is to group several plants together. Plants give off moisture into the air around them. The moisture given off by each of the plants will help to raise the humidity around the whole group.
I hope this helps. If you have any questions or need additional information please don't hesitate to ask.
Thanks
Tracy
