I harvested about 60 dahlia seeds from my plant last year. I planted them under my grow light indoors waited two weeks and nothing. I dug them up and the seeds were rotten. I checked a few unplanted seeds and realized they all were hollow with no embryo inside! I never heard of non viable dahlia seeds?

From what I have read, there are quite a few dahlias that don't make viable seed, some that hardly make any seeds at all.

Ok so that explains it, mine must be of been one cultivar with no viable seeds.

It is usually enough to have a quarter tray of seed watered from the bottom so that it is moist, then just stand the seeds in them like soldiers in ranks with the tip above the surface. You can plant maybe twenty in a quarter tray and they are very tough little seedlings when they have a few leaves, transplanting very easily.

Don't give up, very easy seeds, assuming they are viable at all.

All the best

Peter