I bought my Calathea roughly a year ago, and I don't think it's very pleased with me. Over winter I had to keep it in a darker part of the apartment because of the cold draft. It developed brown tips because of that. This stopped when it was put back in its usual spot. It now has sunlight through frosted glass for half the day and is watered once a week and fertilised once every other week. But it's suddenly done something I've not seen it do before - it's curled up all the grown leaves permanently. Simultaneously it seems to be growing a bunch of new leaves. Is it switching them out? If yes, is that a normal, annual thing?

The funny part is that my other Calathea, a different type of the plant, is enjoying life to the fullest under a fake light. No dry edges, no curling up, turning the leaves towards the IKEA bulb and looking quite lovely. It gets the same treatment, except that I give the displeased one a little bit more water because it's exposed to more sun.

The pictures show my displeased Calathea from two angles. The one that shows the base of the plant is meant to show the young, upcoming population. Apologies for the picture quality, it's a tad dark here.

Calathea rufibarba.
That is odd.
You could cut off the bad leaves and let the nice ones fill in. I hesitate to 'accuse' any of your care since you have another plant very happy. I would pull the plant out of the pot and look at the roots first. You can be surprised at what's going on down there- not like zombies or something horrific, only that it may be much drier or wetter than you thought by viewing the surface.

It almost seems the older parts may have lost their roots, but the young center is still OK. Just a guess. I had a small rufi once and don't still have it, and also lost an insignis, which may tell us these lance leafed Calatheas are looking for something other than how I (successfully) grow my other plants.

Thank you so much for the reply! I had a look, and there were indeed no zombies. I have no experience with this view of the plants - do they look normal? I don't know if I should look further in - I'd appreciate your recommendation. The dirt around the sides felt like it does on the surface.

If they have indeed lost their roots, do you suppose this could've happened because of the long winter we've been having?

that looks healthy, don't dig into it. But seems dry- is it drier than you would expect based on what you see from the top? Maybe it's been too dry.
Up the water but stop, or at least do NOT up the fertilizer.

Got it - I'll do that. Do you still think it's a good idea to cut off the curled up leaves?

Wait on that, since they are only curled and not brown

Alright, will do. Thanks again!

It is not diseased but it does look like it has been under watered. Calatheas don't like dry soil and leaves do tend to curl and develop brown edges when the soil gets too dry. Water it thoroughly as soon as the surface of the soil feels almost, but not quite dry.

The change in light may also be a factor. Plants have difficulty adapting to changes in light. Try to find a permanent location for it.

You can trim off brown edges and prune off leaves that are all or mostly discolored or fail to unfurl after your have watered thoroughly. No need to fertilize more than a couple of times per year and only at half-strength.

Thank you for your advice! I will make sure to follow it