Calathea is super thirsty. More than likely you are letting it dry too much between waterings. This is one plant that breaks the mold when it comes to watering. You cannot let the soil dry out or else it will complain A LOT. They also need a lot of humidity. Try putting it over a pebble tray filled with water. This will help keep the humidity up. I would also give it as much light as possible because it is variegated. If you have a kitchen window above your sink this would be the perfect place for it, or in the bathroom in a window. Do not let the temps drop below 70-75. Ideally I would grow this plant in a terrarium or a wardian case with a under tank reptile heater installed.

Yep. Looks like it needs more water. Also, the first picture shows a root sticking out of the bottom.

If you're not used to how much the plant likes to drink yet, try moving it to one of those self-watering containers. It's a good way to learn how much a plant drinks because you can easily tell if the bottom dish is empty.

Hi, thanks for the answers!
I kind of live in, like...a second world country, so you'd be surprised how hard it is to find some really basic things here...but I'll stop by that plant store today anyway and see if they got those self watering pots and if I can afford to buy one at all. (and if not...well I'll just have to do better.)
The kitchen is really bright but the sunlight isn't direct and the air is a little fresher so they should be okay there. Also the temp is always between 20-22 C (and there isn't really anything I can do about that). I'll try the pebbles thing for now.
And yeah, I know, all the plants have little roots sticking out, they were like that when I bought them, but I pulled one out to check if it's root bound and it looked fine to me (the roots weren't tangled or showing in the sides of the soil) so I just assumed they were all fine since they are the same size. But could this actually be harming the plants? I was going to repot them into slightly bigger pots in the spring anyway.
The soil is still moist bellow the surface so I don't know when I should water it again? I'm really afraid of overwatering.

It is thirsty. I keep mine moist and never any drying out. If you see roots then it is suffering because they are not getting any water. I do not think the plant will last until spring for a little bigger pot because it is such a thirsty plant.

My plant was your size when I purchased a few yrs ago. I have had to share many divisions with friends because they love it and because I do not want to have to move it to a bigger pot. This is a 22" pot without drainage holes. I do not think you can over water but you can underwater this plant and it will die if it is under watered.

It is a Stromanthe sanguinea tricolor

Native to rain forests of Brazil, it requires high humidity and warm temperatures to thrive. Why the internet instructions say let the soil dry before watering is a mystery. If they had ever been to the rain forest of Brazil they would know that would kill the plant. In between the rain the humidity is so high the soil never dries.

(that is one pretty plant :) )
I heard about them being rain forest plants which is why it sounded a little odd to let them dry but I foolishly assumed these people knew what they were talking about. But in that case, she should love it here in the summer....if she lives to see it.

I'll repot it now then, I guess, cause winter's over anyway and it's march so basically, spring. What's the worst that could happen, the poor thing is already miserable.
But my final question (I promise): When repotting, should i completely replace the soil, or just add enough new soil to fill the larger pot? (first time plant owner, so sorry for the stupid questions)

You would want to replace the soil because if you don't this can cause a lot of problems down the line.

Helen if you read any instructions for houseplants they always say lei it dry before watering. So they think it is good for every plant. I have been around plants most of my life. My mother was a plant lover. I have killed enough plants following basic instructions. All instructions are not good just because it is basic.

A little info. My sister loved my plant and asked me to send her a cutting. I sent her one and she called me 6 mos later and said it died and could I send her another piece. She killed that one too. I finally asked her what was she doing. She is my sister and love plants my mother taught us all. She was doing the same thing letting it dry. I told her the same thing I have said here she has now kept it alive for a year.

Your choice, Use a pot with drainage and water at least every 6 dys. Mist the plant every two days. No drainage water about every 7 dys and keep it very warm. If you are new to plants I would go with the drainage but because I know how much water to keep soil moist and not swimming it is easier for me to not have drainage holes in the pot,

Al have you ever grown this plant before?

Yes I have. I've grown it outdoors, treated as an annual in mixed display plantings that I place throughout the gardens & on the decks. It performed very well, as I remember. Why do you ask? Even if I hadn't grown it, the relevancy of what I said would still be as valid.

Al

Just wondering if you had grown it as a house plant long term inside winter outside summer.

It is helpful when we see others that have grown it under various conditions. All things are learned through science, experience and learning from each other. That was the reason for my question.

Was there a reason you did not try to grow it inside in the winter?

Al,

If you did keep a stromanthe/calathea/maranta as a long term plant, would you make any alterations to the gritty mix for it? Would you increase the Turface fraction? Or stick with 511?

Thanks!

Hi, speaking of, I got the basic humus soil and I read that it should be mixed with sand and peat? Is that correct? (if yes, should it be one third of everything or?)

I would not use sand in potted plants.

Sara - I would treat it the same as I treat a peace lily. Because this isn't a particularly fast grower with an aggressive root system, it can often go for 3 years between repotting without serious limitation due to root congestion. If I was growing it indoors, I think I'd use the gritty mix for calatheas that get repotted and 5:1:1 for plants that get divided.

Many growers reason that because in situ plants are often found in wet soil that they appreciate a soggy root environment in pots. They don't, for the physiological reasons noted in the longer post upthread, and the belief they do has created another horticultural myth. They can be grown in various forms of aqua-culture, but will do best in conventional container culture using well-aerated soils that don't support a saturated layer of water at the bottom of the pot after a thorough watering.

Helen - I think you're headed down the wrong road. Humus soil with sand and peat is going to make a soil with a consistency closer to pudding than that of a well-aerated fast draining medium your plant would surely like.

Al

Thanks for the advice-
Would it be too bad if I just put it in the humus then? Or can you suggest something else that I could add? (maybe something that shouldn't be too difficult to find :/ )

Humus is decaying plant (and animal) matter and is usually milled to a
very small particle size for commercial sale; and, particle size is an
important consideration in any conversations about container soils.
Soils comprised of primarily small particles, like you would find in
peat, compost, composted forest products, coir, play sand, builders
sand, ...... generally provide a soil structure that invites a lot of
water retention. Ideally, you would be using a soil primarily comprised
of larger porous particles (and possibly some nonporous particles so you
can 'adjust' water retention if you like) that allow larger pores
between the particles that will hold air when the soil is at container
capacity (holding as much water as it can) instead of the smaller
particle size and smaller pores that filled with water when you irrigate
scenario.

Many growers are using soils that look like these.

You might find this BASIC OVERVIEW to be helpful. If you have interest in checking out a thread with much more info on soils, YOU CAN FIND IT HERE.

Al

Thank you Al.

I really appreciate how many discussions and recommendations you have posted here over the years. I have been reading them for the past year and am still re-reading and trying to pick up all the detail. Thank you for your dedication to helping so many of us.

FWIW Helen, I have had a small calathea & maranta (not the same plant as yours, but the same family) for several months, both still in their nursery pots & mixes, which I have been watering essentially exactly as Al recommends above since I got them (I learned to do that from Al's posts). I expected them to be difficult plants based on their reputations, but they have been surprisingly easy keepers doing it this way. Both have put out several new leaves, and neither has brown tips or edges. I'll repot them into gritty mix this June.

Best of luck with yours!

Well! What a nice effort to express the kind thoughts you shared above. An 'attaboy' now & then sure makes it easier for the helpers to stay enthused about their involvement . Personally, I need to feel like I'm making a difference in someone's growing experience to keep me interested and posting - so thanks very much for your offering. If there's anything you don't understand or want to understand more fully, please don't be bashful about asking. Thanks too, for offering encouragement to Helen, based on your own experiences.

Hava good weekend! Thanks again!

Al

Hi Al, first of all, thank you for always taking the time to explain everything
And you've all been very helpful, I really appreciate it
Al, I read your links. You said: "Soils made of a high % of pine bark or other inorganic particles will have plenty of large air spaces called macropores. These are pores that will not hold water, only air, even when the soil is as saturated is it can be."
Now, unfortunately, I can't really find most of the other stuff you listed in your other post about soil, but- I did find a big bag of something that looks like tiny pieces of bark. Here's a picture of that:

Where do you live, Helen - not looking for an address - just a state and what part of the state or a large city near you?

Al

I don't live in the US though, I live in northern Serbia (central/southern Europe)

I quit reading all the many responses but wanted to add that I have mine a couple feet from an eastern window and I mixed spagnum moss in with the soil the plant came in and the moss keeps it moist much longer so I don't have to water very often and the leaves rarely brown, even in winter.

H - it's always difficult helping growers who live where what sort of container media or components thereof are an unknown. I have a few European friends who use large fractions of an ingredient called Seramis (calcined clay granules very much like Turface) and other amendments to make their soils. Even though I probably can't be of any direct help, I think that if you become familiar with the soil information at the second ,ink I left above, you'll be able to put something together or amend something readily available so it works well for you.

The product in your picture looks like it's primarily uncomposted sapwood/heartwood, which would make it a poor choice as a significant fraction of a container soil for a variety of reasons.

If you feel your medium is too water-retentive, you'll find some very good tips on how to deal with excess water retention if you click this link. Let me know if you think there is anything else I might be able to help you with.

Good luck!

Al

Al, don't worry, you've helped me a lot because now I at least know how everything works and what not to do. I guess I'll just have to improvise and hopefully I won't mess up.
Thank you

You may be able to find orchid bark at your garden shops. It's an idea.

H - I regularly point out that an understanding of the concept is much more valuable than any recipes that accompany the information because it frees you from being locked into the notion that you have to have ingredients A, B, and C to make the concept work. I'll just hope you can find ingredients that can be assembled in such a way that your water retention is adequate w/o a significant PWT. Best luck. Keep us posted as to what progress you make?

Al

Mentha, thanks for the suggestion. I'll stop by one of those agricultural pharmacies (or whatever they're called in English) and see what they have. I also have 4 more plants that need potting up so I might make a new post for all that...if I ever get around to it.
Al, you said that the stuff I have would be a bad choice. If by chance I don't find anything better (which is a very realistic possibility), should I still just not use it?
(apparently my mom used it for most of her plants and they're doing just fine...but then again, her plants are always doing fine)

Let me clarify: Unable to be sure exactly what you're using, the product you have available might be different than the products I've seen used with poor results. My feeling is, they're probably very much alike. Every plant I've seen in the US where the fertilizer sticks are being used was doing poorly and had the look of an over-fertilized plant. Perhaps that comes from a combination of use of the product & watering in small sips, which ensures that all the dissolved fertilizer not used by the plant, stays in the soil. If you must use the sticks, I suggest you work out a plan that allows you to flush the soil regularly - monthly would be reasonable. There are different strategies that would allow you to do that with minimal impact on the plant should the soil's tendency be to remain soggy for extended periods. You can use a little science (see the link I left last Saturday at 6:31PM) to rid the pot of excess water.

I prefer fertilizers with ratios of 3:1:2 or 2:1:2 for everything I grow in pots. Examples of 3:1:2 ratio fertilizers would be those with NPK %s of 24-8-16, 12-4-8, and 9-3-6. I particularly like Foliage-Pro 9-3-6 because it doesn't use urea as a N source. Urea promotes larger leaves and longer internodes than nitrogen in nitrate form, and nitrate N is less likely to be problematic when soils are compacted or partially or fully saturated. If you have stores there devoted to growing plants hydroponically, or if there are stores that cater to pot growers, you could ask for a fertilizer similar to this one:

Al

Hi Helen, I wondered if your plant improved and survived? I posted a couple of days ago about my Calathea (rattlesnake variety) and am yet to receive any replies, so I'm re-reading all the previous posts to see if I can find anything I missed!

Hi, sorry it took me so long to reply...Yes it did recover actually and is actively growing new leaves :D
I repotted it into lighter soil and a slightly bigger pot, although I can't tell you exactly what I used because the stuff I have is different than yours and I couldn't find any of the stuff suggested here, so I just sorta winged it (sorry Al)
I removed the most affected leaves and since then I'm just being careful not to let the soil dry too much. And most importantly, I moved it to another place because this plant really, really hates it in my room. It gets all sad and droopy whenever I try to put it on the window sill in my room, and just perks right back up when I put it back in the kitchen. This doesn't make sense to me, but plants are strange like that.
Anyways, the plant started growing again in mid April and I haven't really had any problems since

here it is now

Hello all,
...from Europe again :). I hope it is all right to revive this topic almost a year later. Helen, I hope your plant still thrives.

I happen to have some problems with my Stromanthe that I thought were rather similar. I took some actions already, it is too early to see the results though. Then I read through all of the above comments and still not sure.

I got my plant around a year ago, it was rather small, and grew rapidly. It did have some very little dry ends since the beginning, nothing major.

This is how it looks now. Constantly growing new, healthy leaves, but it only takes a couple of weeks tll they all become so dry on ends. I did remove alot of leaves already. I keep the soil moist and mist leaves every day, sometimes even a couple times a day. I give it showers monthly. The humidity in my flat is usually 50%.

For a long time I believed it was the humidity issue. Could it be just that?

On the other hand I do have Calathea lancifolia (which I believe has similar humidity preference) and it is doing fine. Maybe there is something wrong with the soil, thought, since it was planted in all purpose soil. Yesterday I repotted into a slightly bigger pot. Got rid of most of the soil while trying not to mess with the roots too much. They looked very healthy but started to overgrow the pot.

I made a new mix (sort of). Since it is very hard to get the basic ingridents here, for "base" I used store bought soil with Osmocote fertilizer and it said "super light" on the package. They do not give actual information on the ingredients here though. It only said it is a 'peat soil' and is reach with humus. I am defnitely no expert on soil, all I can say it indeed was light and soft to touch, maybe it had some peat moss in it (?) and some perlite already, not much though. This is how it looks like, different to what it was in before for sure.

To that I added alot of perlte (around 40 %) and just a tiny bit of orchid mix. I planted the Stromanthe with this mix I made in terracota pot. I am not sure if I did the right thing with all that. The soil soaked up alot of water.

I would be very happy if anyone could comment on that.

I took a risk and planted some big ones in a less-than-ideal office environment recently and I'm paying the price. C. Triostar do like a bit of light, but in an air conditioned office, they are doing exactly what yours is, i.e. lots of tipping leaves.

I keep upping the water, but they keep drinking it all!

Well, air condition makes air very dry. Too dry for our comfort, so I can imagine that a rainforest plant like that is even more fussy about it. ;)
Poor plants. Though it is good to know I am not the only one dealing with this sad dry leaves...

Mine is suffering from the same decease as Helen's. I keep her moist, away from sunny windows, I repoted her and still is looking awfully sad after 15 days of glorious colours and shiny leaves when l bought it. I live in the Tropics, hot and humid wheather. Do not know what to do. She looks like that now.

Seems like she is dying to me. So sad.