Charles,
Ime5573 is correct. The older growth turns a more green color than what you see with the new growth (that yellow neon color). I purchased one at a BBS before that had old growth on it. It was your standard Pothos green color, but all the newer/new growth was neon green. Just the nature of the beast. Nothing to do with lighting, you're plant is fine. :)

Planto

I saw several of these plants at the garden center recently. They were in 8" hanging baskets and were very large and bushy with lots of vines, and entirely neon or very bright light green.

At what point do they become darker?
Or did I see a different variety that retains that brilliant neon color?

Dezzo,
I guess when they get "old enough." Whatever exactly is "old enough," I have no idea. My MIL's had quite a bit of new growth added to more older growth, but in the so many months she's had it, the more older growth still hadn't turned a darker green (although the old growth was already a darker green). I think you saw the same 'Neon,' as I'm not familiar with there being another cultivar with that color.

Planto

There are some that stay that Neon green color even to maturity..I have one ..Then there are some that start neon green and end up green with age..

I am going to say you have the later...Love them

MIke

Mike,
Huh. I will have to find one that stays all neon then. I love the color; the darker green, not so much.

Planto

I finally got out my camera and got a picture, hoping to bring some Light to the conversation. ;-)
Here's a picture of my Neon Pothos, next to a Golden Pothos for comparison. Although the Neon leaf at the bottom center of the picture is darker than the newest leaf, it still isn't as dark as the Golden Pothos. My Neon is still very young, and we haven't had much sun this winter, so I hope the colors will perk up in the spring.
And just to muddy the waters further, isn't there a bright green philodendron? I'm not sure of the exact name, but I wonder how the colors mature on that one?
Lennie in Michigan

Lennie,
There is a "neon" colored Philodendron too. The pictures I've seen of it show the older growth darker than the newest growth.

Planto

My Neon came from a cutting of a friends huge Neon that streams around part of her kitchen. It stays Neon if you will. Mine did but has since reverted to like the photo shown in this post where new growth is Neon, older growth is darker. The original mother plant at my friends remains all Neon.

I just read an article that differenciates neon pothos from lime pothos. Lime being yellow and green leaves. I'm still searching

I have four neon pothos in different locations around the house. They have stayed neon since I've had them, even with lots of growth. There is one on which about three leaves turned green about a year ago, but since then, no more.

I do keep three of my neons in the southern facing windows. Perhaps the intense bright light and the fact that the desert never really gets dark during the day for a long time makes the difference.

I also have one that i have had for a while and it has stayed the bright neon color.

If you want your Neon Pothos to keep the vibrant chartreuse color, then don’t grow it in lower light conditions. The leaves will revert to solid green & get smaller. A Jade Pothos (the one with solid green leaves) is a much better choice for lower light.