moss grows on top of medium

[Cinderella]

Why do some orchids seem to grow moss on top of the medium? I imagine that left untreated this would choke the roots. Does it mean that you need to repot? Or, is it harmless?

[Diane]

Moss usually means one of two things to me - the media has broken down so much that moss is thriving and it's time to repot - or I'm keeping it too wet. In my case, since I grow mostly Catts, I don't often have that problem. But I've had a couple neglected Phals start moss.

Sometimes the spore comes in the potting media - if it wasn't well cleaned.

[mde]

I personally don't think it hurts a thing and I also find it attractive. I have a few bonsai and I purposely grow spores (kyoto japanese moss) in these for the effect.
Other opinions are sure to follow.
Matt

[bench72]

I've got a paph philippinense which has the whole potful covered in moss... and I think it must be happy because there is one mature growth, one almost mature and five new growths on it...

however, I have read somewhere else that with Phalaenopsis it is not good as it cloggs up the air movement or something...

frankly, unless the plant is looking terrible, I keep it and it does look nice as it makes it even greener...

so I'm obviously a newbie grower so read all the above with a grain of salt.

cheers
tim

[ATester]

You seem to be doing nonpurposfully what I am trying to do! What is your secret!! I have a couple mounts, and though the sphag is great at being water retentive, it doesn't have the nice loush green I would like to have growing...the plant, Mtssa. "Izumi" is doing great, but I hope that moss also starts growing.