Burned root tips on cattleya

[getris]

Hi all,
I have several cattleyas in my collection. Apparently they are all doing well, there are plenty of new growth and they all flowered this year. But all the roots have burned tips, aerial and terrestrial. I thought the problem could be type of water, but I use only rain water and I don't fertilize.
Could it be heat damage? Leaves and pseudobulbs are looking great so I am not really sure.
Today I am trasplanting all of them into new potting media, just to be sure.
Thanks

[Ray]

Could be heat, could be too dry (lack of humidity), or could be due to accumulated plant wastes.

[getris]

I moved all my Cattleya to clay pot that should create a more cold climate in the pot. Lack of humidity no for sure: I have 70% - 80% during the day and 90% or more during the night. This week here in Italy was really hot, my greenhouse temperature went up to 34 celsius but now the max during the day is 30-31 celisius. Is it ok or still too much?

[estación seca]

34C is not too hot for most Cattleyas and hybrids. You need good air circulation when it is this warm, so the sun does not burn the leaves. You will probably also have to water more often.

They do better during hot weather if the nights are much cooler. Do you have cooler nights?

[rbarata]

Originally Posted by estación seca

34C is not too hot for most Cattleyas and hybrids.

Judging by my only catt, I was thinking the same. Mine also grows with less than 25% HR so I mist the aerial roots every two days.
But, with 80%, I wonder if it isn't too much. Plus, it might be difficult for the medium to dry.
Just a thought...

[stonedragonfarms]

When you say burned root tips, do you mean that the rest of the root is plump, but the tips are brown/withered? I see this sometimes in my cattleyas that are exposed to a sudden spike in temps coupled with a lack of airflow; it seems to happen regardless of relative humidity, and plants that have any of the unifoliate cattleya species in their background (coccinea, sincorana, etc.) seem more prone to it. If you can increase the air movement at the root zone (ie circulate the air with a fan) it seems to prevent the problem.

[getris]

Thank you all. During the night I usually have 20 celsius so that's not the problem. Could be the air circulation. I will install a little fan to move the air a little more to prevent more deseases. Hope this will resolve the problem