Not really sure what you are describing. Catts can send out roots before or after maturing a growth depending on the plant. All growing roots have green growing tips. Once the roots finish, they no longer have green tips and can be any shade of white, grey or brown. Many Catts send their roots out on top of the media and over the pot. They do not burrow down into the media. Some hate being buried and will not go into the potting mix. This is nothing to be worried about.

When roots are living in a dry environment, they appear dry and are dry on the exposed surface. No big deal.
I've never paid that much attention to roots unless they turn black. Then I look.

Misting can keep the roots looking better, but you must be careful not to over do it.

Don't know if this is the info you were seeking.

Jane

Hi Calvin. I know what you're describing. I've mostly noticed it on catts in bark I've bought at orchid shows. I think what happens is that bark on the surface is allowed to dry out and it pulls moisture out of new roots as they touch it, and the growing tips die. If the growing tip on a longer root dies, the root can possibly branch. These short stunted roots don't start growing again unfortunately.

John

Hey Jane and John - thanks for the answers. Actually I do see roots burrow into the media - (well the ones growing in sphag or CHC at least) which I'm definitely glad for, since I don't water/mist the roots - I only water the media! Most roots do dig in, but some don't and the ones that don't end up dying quite short, so I was just wondering whether it was a sign that the ones in the media have also died (like right below the media so I can't actually see them), or whether they are still going deeper in, and it's just the ones on the outside that have died. :)

If you are not properly watering, in bark and do not see this in chc and spag, especially in winter, it would indicate that the roots are spurning the dry media and seeking an alternative water source. When there is no moisture to be found; they close down; sealing themselves off from further moisture loss through the tips.

Clara

Hi Calvin. The stunted roots are not necessarily an indication of the condition of roots that are in the medium. Bark can be a challenging medium in certain conditions because the same pot of bark can have several different levels of moisture - so the established roots could very well be perfectly happy. You will need to keep an eye on new flushes of emerging roots on plants in bark. If they continue to stunt, then the next thing I would try is bedding the surface of the bark plants with a quarter inch of sphagnum moss which you would mist daily or so. If you don't like that idea, then you could just repot into something that holds more moisture close to the surface.

I do not believe that these short stunted roots are merely dormant. The growing tips have probably died and you won't be able to expect anything from them. Hence the necessity of attending to the problem one way or the other before you lose another set of roots.

John

Thanks again for the replies, John and Clara! :) Interesting to know there's a difference between dormant and stunted roots. I don't grow anything in bark (this plant just came this way and I didn't bother doing anything about it)- I don't even own any of it to repot in, so it seems I've lucked out in my medium of choice then (which is sphag). Good advice - I will keep my eyes open.

Ariel roots will stop growing like you describe when relative humidity is not high enough for them. Many orchids can latter branch out as described by John. The winter is a hard time to keep relative humidity high when you have to heat.