Repotting a Cattleya - what to do with the roots?

[notsogreenthumb]

I'm new to orchids and I have a "Chyong Guu Swan 'Ruby Lip'" from the Cattleya Alliance.

I've read and seen on the 'Net that Catts commonly lose their roots when you repot them, but then generate new roots fairly quickly (I assume if they're healthy).

I saw an interesting video online: Basically, her recommendation for beginners is to just leave any roots that aren't dead, but for folks that have more experience, she says that since many of the roots will die anyway, she normally cuts all or almost all of the roots except for the roots on the newest 2 or 3 pseudopods. By doing that her new potting won't end up being full of dead rotting roots in short order.

What do you folks think? Leave them all (except those that are already dead), or trim back except any that seem really healthy or more importantly are on the newest couple of pseudobulbs?

I understand the way these grow and can tell which are the newest pseudobulbs. But then since I know so little about orchids, I could easily be very wrong.

Thoughts?

[Fereydoon]

Hi, i have Cattleya orchids that grew new roots on a old bulb. whether the roots die or stay alive depends on your growing environment and the genetics of the plant. i think don't cut any healthy roots and just trim the dead ones. I grow orchids in Tehran so in my environment New Zealand sphagnum moss work best for me.

[notsogreenthumb]

Great, thanks for the data point.

[JDT]

In talking to some of the nursery owners here in South Florida they suggest first cutting out all the dead roots then giving a haircut of all the good roots leaving about 2 1/2 inches, they then will sprinkle the cut ends with cinnamon which helps eliminate fungus then pot them up. You are correct on the direction Cattleya grow always forward of new growth never from old growths so put the older growth up against the pot so it will have plenty of room to grow and secure with a pot clip, you don't want them to be able to move around in the pot until the new roots attach to the new media or pot and stabilizes. There are a lot of good videos on repotting orchids on YouTube, check them out!

[notsogreenthumb]

Good info, thank you. I'm jealous of my mom who lives in Vero Beach and can grow orchids by strapping them to the tree in her back yard.

[JDT]

Good info, thank you. I'm jealous of my mom who lives in Vero Beach and can grow orchids by strapping them to the tree in her back yard.

If you lived in Vero you would become an addict like the rest of us so you might be better off in your apartment with limited space!

[Dorsetman]

If you don't live in a good orchid environment - like 95% of us - then be very careful with cattleyas. They do NOT grow new roots just like that. Ol;d roots branching after a cut, yes - but that is different from producing new roots from the growth.
The only orchids capable of producing new roots from the growth at any point in the cycle of growth are paphs , as far as I know.
Cattleyas will produce a flush of new roots at a specific point in the cycle , and that point is different from one species to the next , or from one hybrid to the next ( according to which species in its parentage is dominant). So, some produce the new roots just before starting a new growth ( those are the easiest.) Some produce the new roots from the new growth when it is small - those also are easy ; some produce them after making up the new growth before flowering , and others only after flowering - those are the most difficult , because if you cut or damage roots, the plant has to complete its cycle of growth on those damaged roots before ever it can get any new roots. If you want to find out more about this, I recommend the Chadwicks book "The Classic Cattleyas"

[notsogreenthumb]

Yowza! Crazy growth cycles. Thanks for the info, Geoff!