Is this medium ok for my orchids?

[RosieC]

If the mix is in good condition (not decaying or smelling) then maybe it could be mixed with other things to bring it into line with what you need.

I'm not good on knowing what needs what, but Cymbidiums in my experience grow a lot of roots in a season, and you are meant to remove about 1/3 of the root mass anyway so I think if roots do die back somewhat then repotting early in the growing season gives plenty of time for new ones to grow and replace them before the winter.

You might need something more water retentive for the Cyms. My mix contains a light foam substance (not dense so will only hold a little water not masses). I'm not keen on something so artificial but the idea is that it is free draining while still holding enough moisture.

For Miltoniopsis I've preferred finer mixes, but I'm not really sure what they prefer. It might be best to repot that when there are new growths appearing, as those will produce new roots. Mine lost a lot of root after it was repotted, but it's new growths put out a lot of new root and so it's doing fine.