Turning yellow

[larry]

My neps in the terrarium are looking a bit yellow, not dark green like before. I'm wondering what causes this? Could it be too much sun, not enough sun? Or humidity, amount of water, temp? My neps get 2 hours of direct sun in the morning followed by 10 hours of being under flourescent lights. Humidity is very high, and I water them every 2-3 days. The temp is around 75-80 during the day and 60+ at night. These are lowlands btw.

So what factors causes leaves to turn slightly yellow? I'm thinking the 2 hours of direct southern california sun might be too intense

 

[GEORGE-CP]

Larry, how long have you had the plants in that kind of light?

 

[larry]

I had the terrarium outside, but moved it indoors since it got cold.  I've had it in its current place for about 6 weeks.  The lighting setup is the same.  When it was outside, it got about 1 hour of direct sun, although the sun was much hotter when it was outside (summer/fall).  I'm really curious about what causes leaves to turn yellow.  Slightly yellow, not so yellow that the plant looks like it dying or anything.  They all seem healthy and are continuing to produce larger and larger pitchers.  I just miss the green  

 

[GEORGE-CP]

what it sounds like to me is if you had them outside and then brought them in and put it under the light fixture. its the light fixture that are turning them yellow and they are getting used to the light from it.

 

[larry]

George, they had the same light fixture outside. Since 1 hour of sun isn't enough, I had the lights on for them outside as well.

 

[Tony Paroubek]

Diagnosing lack of vigor or something broad spectrum like this is very very difficult from description. I am making a guess based on the most common problem I have seen with lowland Nepenthes getting pale or yellowish

Temps are too cold is my bet. You say 60+ at night.. is that 60-61 or 68-69?? They will manage ok with 68-69 but even that is marginal for lowland Nepenthes at night.

HOWEVER there are a dozen other possibilities that either could be causing it solely or in combination.

Morning sun being 6-8 am or 10am to noon Big difference there.

Also wondering is it the whole plant getting yellowish? Just the old leaves?? just the new leaves developing??

Do you feed them either with fertilizer or insects??

What kind of water do you use?

They were perfectly fine until you moved them inside? If so what is different now? Temperatures? Light levels?
Tony

 

[larry]

Tony, I think you are right about the temp, that's main thing that changed. Several months ago, the weather was still hot and the temp in the terrarium got up to 90 degrees. Now its mainly 75, reaching 80 when exposed to the sun. At night, its around 60 +/- a few degrees.

They get morning sun from 8:30-10:30am. Except for the new growth, the whole plant is a bit pale. New growth starts out green, but gets pale within a few weeks. What do I mean by "pale"? Hard to describe. Not too yellow, more light green.
I'd post a pic, but it'll look different on different monitors.

I give them a dose of Superthrive once a month and I feed them flies every now and then. I water them with R.O. water.
Other than paleness, growth is even more vigorous now than before. The reason why I think it may be the sun is because, neps towards the back of the terrarium get less exposure to the sun, are a bit greener, less pale. Maybe I'm overly concerned.