"Orchid mold"

[Dusty Ol' Man]

I was in discussion with someone with a white mold issue on a Hauserman orchid. I suggested they pose their question here. The reply was they did and everyone suggested new medium and a repot. They said "Orchid mold doesn't work that way". I asked how "Orchid mold" differed. Here is the response. Any truth to this?

Mold produces spores. All mold, including white orchid mold. Spores can't be "shaken off" as the folks at orchid board suggested. Nor will it magically disappear when you replace media, since white orchid mold literally adheres to the root system.

Once it has a suitable substrate and moisture, it will produce hyphae, and continue spreading into new media as soon as it becomes moist. Then it will produce mycelium, which is the gross mushroomy smell.

[Roberta]

What, exactly, is "orchid mold"? Orchids may have a symbiotic relationship with mycorrhizae in their environment. Many terrestrial orchids require very specific organisms in the substrate. (That is why temperate-zone wild orchids are very difficult to maintain in "captivity") But mold that grows in orchid pots typically indicates that there is not enough air, and that the mix is broken down. This is a hostile environment for epiphytic orchids, which need "humid air" more that "wet" around their roots. Hence the advice to repot. It's not that mold itself is so bad (though it might be) but it is an indicator of an unhealthy environment for the orchid.

[Shadeflower]

I think the advice was spot on.

mold is not a problem as such. Like if I see mold I don't urgently rush to fix it.

The orchids can live happily side by side with white molds.

BUT the prsesence of mold does indicate a problem and the only way to fix it is to change the substrate - it stays too soggy, too stagnant. If it were the right substrate and there are no rotting roots then mold would rarely form.

But because mold formed that indicates

a) the substrate needs to be changed

b) throwing out as much of the old mold and the spores is highly beneficial in stopping the mold returning.

ORchid roots are meant to periodically dry out, this dries molds which don't survive the long term wet and dry cycles that orchid roots thrive under.

So once again mold is not a concern but the presence of mold is a concerning indicator that needs to be addressed.

How exactly was he going to fix it then or was his reasoning that there was no problem in the first place?

Of course he wasn't going to be happy with any answer..

[Dusty Ol' Man]

Both of you: that's what I said. This person's response didn't make any sense to me, k owing what I know about mold and how it is controlled. I have extensive experience from having a hurricane blow through my home. This was just something I had never heard before and I thought I'd see what you had to say. Anyone else have an opinion? I'm all ears.

---------- Post added at 11:20 PM ---------- Previous post was at 09:23 PM ----------

Originally Posted by Shadeflower

I think the advice was spot on.

mold is not a problem as such. Like if I see mold I don't urgently rush to fix it.

The orchids can live happily side by side with white molds.

BUT the prsesence of mold does indicate a problem and the only way to fix it is to change the substrate - it stays too soggy, too stagnant. If it were the right substrate and there are no rotting roots then mold would rarely form.

But because mold formed that indicates

a) the substrate needs to be changed

b) throwing out as much of the old mold and the spores is highly beneficial in stopping the mold returning.

ORchid roots are meant to periodically dry out, this dries molds which don't survive the long term wet and dry cycles that orchid roots thrive under.

So once again mold is not a concern but the presence of mold is a concerning indicator that needs to be addressed.

How exactly was he going to fix it then or was his reasoning that there was no problem in the first place?

Of course he wasn't going to be happy with any answer..

Here is his further response.

It's how fungi work. I grew mushrooms for years. Air movement helps prevent *new* spores from getting a foothold. The same way air movement can help reduce fungus gnats - they just can't reach the substrate because of the moving air. Once they are established in a substrate, it won't do much since it's growing inside the substrate (a.k.a. colonizing).

If that was false, mushroom grow houses wouldn't work since they wouldn't be able to have ventilation since it would kill the mycelium before it produces fruit bodies (mushrooms). Anyone who has been near a mushroom grow house can attest to how well they exchange air.

[Ray]

FWIW, Orchiata bark contains both trichoderma and penicillium molds, which are beneficial at preventing some diseases.

[Shadeflower]

Dusty at some point you just have to conclude some people took one too many magic mushrooms.

So he is saying the reason changing the substrate is bad advice because air flow prevents mold forming?

I'm sorry but I just cannot follow the logic

[Roberta]

I know that if I had visible mold growing in my orchid pots, I'd repot. No need to theorize... I'd consider it an unhealthy environment for epiphytic orchids and seek to remedy the situation.

[rbarata]

Roberta, where are you? I can hear lots of echoes.

[Roberta]

Yikes, I'll clean it up. I only responded once... Someplace in cyberspace... Now it's there only once...Thanks !

[Dusty Ol' Man]

Just for the record, after the poster reiterated his position, and after I tried to make a rather truncated argument that molds (of the variety being discussed) don't qualify as fungi (for the purpose of the problem under discussion) and qualified his statement with this webpage
What is the difference between Mold and Mildew? | US EPA
I gave up. I had suggested the poster come here for help and got this response:
I am in some FB groups with Ray so I might try there. Good call!

I kinda lost faith in orchid board when I received a plant from Hauserman's that was covered in white orchid mold and reeked so strongly of rotten mushrooms it made you want to retch. Every single response told me to ignore it, shake off the old media, and just repot it.

That's just not how orchid mold works. I kinda stopped posting there after that since it made me question how much a lot of their posters actually understand about plants and fungi.

If anyone wants to pursue this, here is the link to the conversation
Question about water culture to rescue a rootless Phal - what kind of water do I use? : orchids