If I had a tuber that was moldy, and yet still firm, I would wipe it off; coat it with some bulb dust or dip it in a mild solution of bleach; and then plant it.

If the tuber was soft, that is a different story. I would insist on a replacement.

Mold can happen, but we want to avoid it if at all possible. Mold can definitely cause problems for all plants including dahlias.

Hi jroot,

Thanks for the advice. The tuber is actually brittle and crumbly, so I asked for a substitution. I was appalled that they did not just provide a substitution when I mentioned the mold. They charge a premium for their tubers and should provide only the highest quality product.

I agree that mold can cause problems for all plants, and do not want to add it to my garden. Who knows what it really is.