most if us do NOT believe misting does anything...

never repot a stressed plant.. unless you figure out why its stressed first.. so we cant tell now.. if that was the right thing to do.. or you made it worse ...

there is nothing wrong with bigbox houseplants.. for the most part ...

unless your furnace is blasting 24 hours a day.. i doubt you have humidity issues in your house. .. so i doubt the humidifier is needed nor doing anything for the plant

i wonder if lack of proper light is the issue ... describe how much light it gets..

what do yo mean by regular soil.. did you put mother earth in a pot.. ??? ...

i never heard of adding egg shells to houseplants...

and finally.. do you ever let the plant and medium.. dry out... i let all my houseplants dry between waterings.. and that is why self watering pots are not my favorite...

if possible.. i would probably put it outside in full bright shade for summer.. and odds are.. by fall.. it will have recovered.. or die.. and put me out of its misery.. lol ...

ken

Thanks for the quick reply.

"most if us do NOT believe misting does anything..."

Misting once per day will not do much, I agree. However, regular misting should slightly increase the humidity around the plant.

"never repot a stressed plant.. unless you figure out why its stressed first.. so we cant tell now.. if that was the right thing to do.. or you made it worse ..."

I suspected root rot, that is why I re-potted it.

"there is nothing wrong with bigbox houseplants.. for the most part ..."

For most cases, I would agree. In this case, however, that was not a good decision. From what I have gathered, buying large, mature, tropical houseplants like Calathea from big-box stores is not a good idea - it is preferable to buy such plants when they are still small so that they will grow/mature in one's environment. This way, there is a higher chance that the plant will survive.

"unless your furnace is blasting 24 hours a day.. i doubt you have humidity issues in your house. .. so i doubt the humidifier is needed nor doing anything for the plant"

The humidity in my house is around 50%.

"i wonder if lack of proper light is the issue ... describe how much light it gets.."

There is a grow light about 1.5 meters above the Calathea for approximately 12 hours per day.

"what do yo mean by regular soil.. did you put mother earth in a pot.. ??? ..."

A cheap, all-purpose soil mix from the store.

"i never heard of adding egg shells to houseplants..."

There are a few benefits of adding egg shell powder to the soil (e.g. promoting plant growth).

"and finally.. do you ever let the plant and medium.. dry out... i let all my houseplants dry between waterings.. and that is why self watering pots are not my favorite..."

While the Calathea was in a self-watering pot, I would always make sure that there was some water there, which was most likely a mistake. Now that the plant is in a 'regular' pot, I let the soil dry out.

"if possible.. i would probably put it outside in full bright shade for summer.. and odds are.. by fall.. it will have recovered.. or die.. and put me out of its misery.. lol ..."

I appreciate the advice, that was my plan as well; however, I doubt that the plant will survive for 5+ more weeks.

Your Calathea Burle Marx is beautiful! It looks very similar to my Calathea Zebrina.

Thank you for the suggestion. I might try the Burle Marx variety. Hopefully I will have better luck with it then with the Medallion.

I have also had very poor luck with the related genera Ctenanthe or Stromanthe (often sold in big box stored too). Seem to die almost immediately.

That is unfortunate. I wish these tropical plants weren't so picky.