Ugh- moldy bark!!

[ccrow]

I just dumped some potting mix in a bowl to find bark stuck together in clumps with a greyish-white cobwebby-looking mold... can I bake this in my oven and still safely use it? I certainly hate to toss it but I'm not going to risk my plants...

[Cym Ladye]

Throw it into the garden or return it to the store where you bought if it is newly purchased. Then start with a fresh bag, hopefully from a different source. It is apparently an old bag stored wet. If you have had it for any length of time, it is probably your fault, but I have known nurseries with old stock having the same result.

I have tried to sun bake this but it never works for orchids and always comes back when used in pots.

[ccrow]

No, it's definitely my fault; it was a partial bag from the last repotting session. I thought it was completely dry but I guess not. Since it came from repotme.com I hate to waste it($$)... has anyone had success with actually baking it in the oven? Anyway, lesson learned- when I have any leftover I will bake it to make sure it's dry before storing!

[estación seca]

What you have are coir chips, also called coconut husk chips or CHC. They mold when kept wet. The white fuzzy mold attacks dead plant material only. I too would be tempted to bake it and use it.

[ccrow]

I suppose I could also spray the heck out of it with my copper-based fungicide.... thoughts, anybody?

[Leafmite]

You could soak it in a bleach solution, then bake it. That should get rid of any mold. I have had to do this with mounts that I wish to reuse that have suffered from mold issues in the past. After the bleaching/baking, rinse well and soak in some distilled water to remove any residue. No need to use fungicide.

[estación seca]

I can't imagine high amounts of residual copper would be good for orchids. Also, there are lots of microorganisms living in almost any potting medium, and a lot of them keep other ones under control. Using compounds that kill off all the beneficial organisms might not be a good thing.

[Leafmite]

I agree that using a fungicide isn't very wise for this application. :|
I, personally, would not use the medium for orchids but that doesn't mean you must waste the good money you spent on the stuff. Growing some strawberries and maybe a top-hat blueberry bush would be a great way to use the medium. Or, maybe a small citrus tree, gardenia or jasmine would work. Add a little peat and sand and you will have a perfect mix for any low pH plant. If what you want to grow requires a higher pH, you can always add vermiculite to the mix.

[bil]

Here's my two cents.

I never throw bark away. I let it dry, sieve it and recycle it. I'll pot orchids in a mix of new and old. The dust I use with the ferns, and anything really dodgy I would again mix wiith soil and use in the ferns.

I wouldnn't use opper. As was mentioned, residual copper? Not a good idea I hear. I'd soak it with a fungicide like mancozeb, dry it in the sun then when it was dry, put it in a black container and put it in the full sun with a lid on. If that didn't kill the fungus, nothing would.

[ccrow]

Well, it's been baking in the oven for about 3 1/2 hours... I emailed repotme.com and got the answer I expected: "no, don't use it(so you can buy more!)" Anyway, I opened the new bag for the repotting I've been doing today. I've been mixing in a little Schultz orchid mix I had hanging around, just to use it up. I think I have just moved over to the 'use dry medium, then soak the pot' camp, lol. I don't have to worry about drying it if I don't get it wet before using it.
I guess I will try the bleach and rinse method, and figure out something to use it for later. bil, you don't rinse before baking? Doesn't it make everything smell of bleach?:-/