Mary - What I did last year was take a gallon sized ziplock - add about 1 cup of vermiculite, and about 1/4 of a jar of cinnamon - then put in 4-6 tubers at a time and tossed them around, When the cinnamon coating on the tubers started looking light, I added more to the baggie. I went through about a jar and a half cinnamon for 400 or so tubers. I don't think that would work so well with whole clumps. I have heard of others just dusting any cut part of the tubers.
