"Cottoney/Spongy stuff" in mix.

[Miller]

I did not use any disinfectant on it but i did wash the roots and used a new pot. Like I said, it had the most healthy roots so I don't think it was causing a problem for the orchid just looked gross. You never know so better safe than sorry.

[Brutal_Dreamer]

I thought it was going to be rockwool, but turns out that is some kind of mold. I would make sure you have very good air circulation around your orchids. You shouldn't see mold in your orchid pots normally. Glad the roots were fine though!

cheers,
BD

[Dazed]

K that looks familiar, it kept coming back in one of my catts and a phal, it eventually started to get these tiny little white bugs. Finally switched them to s/h and no prob, after a bath in peroxide and bleach water of course.

[max]

Miller it looks like a fungus but nothing I would be concerned about (as long as the plant looks healthy) as there are many different kinds and only a few of them are harmful to plants. But this one looks like its braking down the bark which can feed the orchid in the most natural form.

[Miller]

Bruce that was my main concern, it looked as if it may have been blocking air circulation. Once I took everything apart I did not fin one dead root, they all looked really good. Now I am thinking maybe it was a good thing as Max has suggested. Oh well new bark and hopefully a happy orchid.

[serama]

I find those white strands (hyphae) in most of my orchids that are in a bark mix and they do not harm orchid roots at all. I know which pots contain a good amount of these as they produce teeny-tiny mushrooms that poke out of the bark from spring to autumn.

And here comes the science lesson for today:
The white cottony strands belong to a small fungus that breaks down lignin (the complex polymer that makes bark and tree trunks extra hard) from DEAD wood. They live everywhere: soil, leaf litter, dead branches and trees that fall to the ground, etc... and any bag of orchid compost that has bark chips in it will contain spores of these fungi. If the bark is kept bone dry, then they won't germinate, but if it is kept even slightly moist (as it is in our orchid pots, baskets, etc...) then they will start to grow. They are part of the normal mycorrhizal community in most places and there's a good chance they can actually form a symbiotic relationship with the orchids (they definitely do with living trees). They are actually very important little things, since only a handful of bacteria can degrade lignin, which is one of the most stable and hard-to-break-down biological substances in the world. Therefore it is up to these fungi and their relatives to perform the important task of breaking down dead trees and recycling the carbon locked up in them. Without them the world would be littered with dead trees.

As I say, they won't damage the roots of your orchids per se, but once they've grown big enough to actually produce mushrooms then they are a good indicator that you'll need to repot the orchid within a year or so as you'll know the bark is being decomposed more quickly by them. BTW, if they do form a symbiotic with your orchid roots, then they will always pop up in the pots where you grow that orchid. They will still pop up even if you change all the medium for clean, sterilised and even autoclaved medium, as they will be inside the orchids roots themselves (where they will be feeding micronutrients from breaking down the bark such as metals and phosphorous to the orchid, which in turn feeds them with simple sugars it makes via photosynthesis) and then grow into the new medium from the roots. If you change to a medium that doesn't have bark in it, then they'll eventually die out of course, like Tamara said.

Interestingly, they do not seem to grow in mixes that contain a lot of sphagnum, which has antimicrobial properties itself. I personally don't like to mix sphagnum with bark though, because once it starts to break down the medium becomes too acidic and, in my experience, that itself kills orchid roots in record time. Although I have to admit that I'm a big fan of growing many orchids in pure sphagnum (or mixed with some perlite), which I find doesn't break down that quickly.

[Miller]

Well I enjoyed the science lesson. Thank you for the insight.

[Miller]

Now you have me researching rockwool, never heard of it before this thread!

I thought it was going to be rockwool, but turns out that is some kind of mold. I would make sure you have very good air circulation around your orchids. You shouldn't see mold in your orchid pots normally. Glad the roots were fine though!cheers,BD

[remo]

It is just mold. I've seen the same thing with mediums that have lots of pine bark in them. Physan 20 will take care of it. Simply do what Coeruleo did and repot after bleaching. Works great when done right.
Remo