Color change

[Piper23]

It looks like I have 2 Catts in the same container- one of them is developing a purple hue in its leaves. The other had a leaf yellow and dry out- it now has a second leaf starting to possibly do the same.

It/they is/are currently living on a heating mat and a thermometer/thermostat keeps the root zone around 72. It is getting 14 hours from a grow light. I water it once to twice per week depending on how dry the media gets and fertilize it weakly/weekly with MSU. It also gets Cal/mag once every 4-6 weeks.

Is purple okay? Should I separate the 2 Catts into their own pots? Other thoughts? Pics attached.

Thank you!

[Roberta]

Some Catts. especially those with dark flowers, will show red color in the leaves especially in high light. It is very possible that you have 2 plants in there, but I would suggest to wait on any repotting until you see new roots. You may need to increase the watering, the heat mat will make it tend to dry out faster.

[rbarata]

Originally Posted by Piper23

Is purple okay?

You should investigate this term: Anthocyanin

It's a pigment that in plants causes a reaction to light intensity, the same reaction as we, humans, experience and know as "tanning".
In case of plants with high light requirements, this is usually a sign that the light levels are adequate.

[alecStewart1]

14 hours from a grow light is probably a good amount of light, so the "purpling" is probably what rbarata mentioned, anthocyanin. It's not in itself a bad thing, but your plant will continue to make it's leaves purple-y under high light.

Usually, this is due to the intensity of the light when using grow lights, so maybe get the plant a couple of inches away from the light, or move the light up a couple of inches.

If it keeps happening after you've moved the plant or the light, try 12 hours of light exposure.

I would also do what Roberta says, just in case.

[estación seca]

Almost no epiphytic orchids in habitat get 14 hours of light. 10-11 hours in winter is enough. Seedlings do better in lower light levels, with no purpling. Those need more frequent watering - they're shriveled.

[Relemitty]

I have heat mats under my Catts, Dens and Oncs over winter.
The heat rises up through the pot and takes the moisture with it.
I water those on the mats at almost summer frequency, every 3 days.

[estación seca]

I decide when to wster by looking at the plants. Those are shriveled and need more water.

[Dimples]

Watering on a set schedule is convenient for the grower but doesn’t always work for the plants. Having a set schedule for *checking* if plants need water is great.

I don’t grow these, but your plants are displaying the classic signs of stress (slight shriveling, purple coloring). Like the others have said, reduce the light duration a bit and try watering when the plants need it, not by a schedule. You can also try placing a plastic barrier on the top of the medium to slow evaporation.

I give my phals. very high light and many develop reddish/purple coloration, which is fine, but they’re not young plants. Babies need a gentler touch.