Mold on clay pebbles

[opal]

Three years of growing orchids. So far no problems. This year - mold. I have all my orchids in clay pebbles and that seems to be the best medium for me and my plants. I have been repotting yearly evenso (while clay pebbles are supposed to be forever). I always disinfect pebbles by pouring boiling water over it before I repot.

A month ago I discovered one of my orchids having a strange smell when wet so I checked and removed a pebble completely covered in white spores. Now I have discovered another orchids giving the strange smell and it has moldy pieces of clay pebbles in it.

I am kind of running out of good pebbles here, every new bag I buy contains smaller and smaller pieces, which makes it hard for me to fill even 1 cup with big ones, and others just being too small to use on orchids.

Is there any way I can clean porous material like clay pebbles completely? Did anybody succeed in doing so yet? Would combining soda and vinegar hurt the orchids? It will give way higher pH than they like if I do so, but that seems the only natural way of getting 100% getting rid of spores from porous material....

Any thoughts?

[Ray]

I would not suggest using either of those chemicals in a way that will expose the plant. The baking soda is high in sodium, which can be toxic if the plant absorbs too much, and vinegar is a tremendous herbicide all by itself.

If you cannot get something like Physan, unpot the plants, bake to pebbles in the over at 500°F for about an hour, let them cool, then repot.

Unfortunately, it is also likely that your plants are infected.

[ezil]

I use Leca pellets quite a bit, and I too, repot at least once a year. I think it's better for the plants. After soaking the pellets in a bleach solution I rinse them thoroughly, and then throw boiling hot water over them. Baking is out of the question in a shared living space, but so far my method works. Hopefully you'll be able to get better quality pellets soon, it sounds like the pellets themselves are the problem.

[keithrs]

Rays way of baking them is probably the best way...

Water is likely to spread any spores.. Even if it is hot water...

You can soaked/agitate them in bleach or H2O2 then give them another soak, than bake them as high as your oven will go... This is how I clean razor blades I use to cut infected part off.