No guest. The tuber is next years store for the plant to regrow after dying down over the winter. Store it deep in the ground or dry and store in a cool, dark, dry, frost free place. I should leave the seed use to the experts. At least with a tuber, properly labelled, you know what will come up.

Dahlias are not that hard to start from seed (from the flower head). For me, it is fun to collect the seeds from plants that don't come true to have a different flower. Day lilies are like that, and if I liked dahlias more, I would do the same with them. But I have done the collerette types and Bishop's Children, which gave a really rich red. T&M have germination guides on thier website.

Twice Ive grown dahlias from seed inc this presentyear despite a bit of earwig damage they never fail to prform and give alate blast of color when some bedding is looking past its best.I always buy the seed and save tubers

you can buy dahlia seeds from your local garden centre , be assured that dahlia tubers are bought in larger packets