Calathea – troubled leaves and new growth

(Question)

Hi there,
I’m hoping to get some advice for my suffering calathea. As you can see, the leaves stay curled and upright. It took a while when I first got it to figure out what it needed within the conditions of my apartment, but after months of ups and downs, I had it sorted out and it was a bushy, healthy, colourful plant. Then this past Fall/Winter, it went through a period of inconsistent watering (too little for too long), where it was starting to crisp up at the leaf tips and lose it’s pink stripes, but after some regulating and care (consistent watering, misting and increasing humidity), it seemed to re-adjust. It even began growing a few new leaves (in the middle of winter..?). Around late Feb/March, it started losing its leaves, and overall lost 1/2-to-2/3 of its size. I think you can see from the picture all the holes where there were leaves – it was really shocking. The remaining leaves stay curled upward with browned tips (see pic). I wasn’t sure what to do with it, thought it might be the end, but figured I’d see if it got happier in spring. The old part of the plant hasn’t, but it does now have new growth coming in. These new leaves seem a lot shorter than the rest of the plant, have their pink stripes, and seem minimally crispy ended. I’m not sure how to care for the plant at this point: Should I cut off the older rolled up/dried out leaves (can it handle that much pruning)? Is there something I should do for the new growth so it doesn’t get affected by the old? It needs re-potting (the roots are pushing out of its pot at the bottom) and soon a change of location as the light patterns are changing and it’s now probably starting to get too much direct sun. However, that’s a lot of change all at once, and I’m not sure what to do with the existing/older leaves. Any advice on what may be wrong with it/how to care for it going forward is greatly appreciated.
With sincere thanks.

(Answer)

Hello, thank you for contacting the Toronto Master Gardeners for help with your Calathea.  Judging from your photograph and description I believe you to have Calthea ornada “Roseolineata”.  These are closely related to Marantas (Prayer plant) so if you ever wish to get another house plant, choose one of these as their requirements are almost identical!

You seem to have had your ups and downs with this plant but I am sure we can get your plant back to a healthy condition.  Let’s look as the growing conditions favored by these plants:

Light:  Calatheas prefer bright but not direct light.  Too strong a light will indeed crisp up the leaf margins.

Temperature & Humidity: Calatheas like a steady temperature between 15 and 21 c. Your plant would suffer if its kept any warmer without high levels of humidity. The same is true during the dry winter months.  You can increase the humidity with a humidifier, by daily spritzing and/or standing your plant on a tray of wet pebbles or damp peat moss.

Water:  These plants need a high level of moisture during their growth cycle (spring and summer) but you can reduce the watering during fall & winter, however never let the soil dry out completely.  These plants don’t particularly enjoy tap water (I know!  so fussy!) You can keep them happy by filling your indoor watering can and letting it sit overnight before watering, this way the minerals sink down to the bottom of the can.

Fertilizing:  During the growth cycle, you should provide your plant with an indoor plant fertilizer every two weeks.  You can eliminate this during the fall and winter months.

Re-potting:  At last we have come to what I think is the immediate problem with your Calathea.  They need to be re-potted into a one size larger pot every year.  Seeing the roots coming out of the bottom of the pot is a clear sign to re-pot.  This is a fine time to do so.   I would take off the most damaged leaves, leaving the smaller young ones.  Re-pot with a soil mix formulated for indoor plants, and for your first feeding, dilute the fertilizer by half the recommended amount.

It will take a little time, but I am sure with this “rehab” you will see your plant thrive again.

Here is a link that you may find useful:

https://www.torontomastergardeners.ca/gardeningguides/beginners-guide-to-growing-houseplants-a-toronto-master-gardeners-guide/