Repotting cattleyas from moss into bark/When is the growth cycle deadline to repot?

[BrassavolaStars]

Hello all,

This post is related to a previous post I made about repotting.

I have about eight or so cattleyas (mostly acquired from eBay) potted in moss. I have always heard it is better to have cattleyas in bark and would have them in a bark mix without upending their growth as some are not in the best state right now and are recovering from various setbacks.

I know the best time to repot a cattleya is when the new roots are about to emerge or are just emerging.

My question is when in the growth cycle is it too late to repot? When the roots are 3 inches? When the new growth has completely matured? When the roots stop growing completely?

I have a few examples attached below of plants I am not sure about repoting

I ask this because I have a few cattleyas that are in old moss (some are pictured) that I should have repotted in the summer but did not because I was busy. They now have mostly mature new growths and roots that still have green tips, but are longer and the green tips are starting to turn whitish (an example attached below).

I assume I should just wait until another new growth appears.

I am just curious when the exact deadline is for repotting in terms of the growth cycle.
Thanks.

[thefish1337]

i look for new roots to form on the newest pseudobulb and then repot. looks like that might be the case on at least one. i'm sure others with better conditions can be more flexible. cattleya can also fail to establish if not well supported so make sure the plant is stable when you repot until the roots establish.

[Ray]

There is no specific "deadline", per se, but the just-as-roots-are-emerging stage is the best, and the more time before or after that, the more you need to "baby" the plant a bit.

If the existing roots grew into damp moss, they will suffer a bit in dry bark. You can reduce the shock by keeping the bark wet until new roots grow, warm up the root system by placing them on a heat mat, and of course, but treating the plants with a good root growth stimulant like KelpMax - basically anything that you can do to stimulate root growth.

[Roberta]

If it is still pushing new roots, you can safely repot. As Ray (and others from time to time) have pointed out, it's the new, growing roots that will adapt to the new environment. The ideal time is when they're just emerging... since some damage to some of those fragile root tips is bound to happen, if it's just getting started you can be certain that there will be more on the way soon. If the new roots are several inches long, the challenge is to repot them without damage... tricky but doable. Don't try to remove any old medium that doesn't fall off easily... you'll cause far more damage than might be caused by having the old stuff around. Place it in the new pot with the oldest part against one side to maximize growing room (opposite of what looks like is happening in the picture), add new bark and tap to help it get into spaces but don't push. You can press to compress bark (and stabilize plant) on the back part where there aren't new roots. Keep hands away from the active front part as much as you can. From your photos, there are plenty of older roots to help stabilize the plant.