I'm lost and sad as I see my new Hypoestes phyllostachya dying and am desperate. I do not know what to do. I bought a week ago, and I brought from Japan to Barcelona. Survived perfectly the trip and 3 days in Barcelona in its own small pot, then yesterday morning I decided to join with other 3 small plant in a bigger pot. I added a bit of substrate and water, put it inside and after 6 to 10 hours become weak, with its steam and leaves down with not energy at all. I took out and back to its small pot, put it in a more shinny area, but still weak and even worse.. What is happening, what can I do? I've never seen a plant in less than a day become like that, like dying.. Temperature is 18-24 degrees C. and the ground is wet.
To large of a pot and excess watering likely are the reasons for you plants health.
Allow the soil to dry slightly between watering.
Your plant may or may not come back from the stress.
Time will tell.
Here is a link to refresh yourself on the care of a Polka Dot plant.