Answer: Dahlias are almost always (I would say 90% of the time) offered as tubers. The reason being it would take a VERY long time to get a reasonably sized plant from seed. It is very hard to find seed for this reason, and if you harvest it from dahlia you already have, chance are you won't get the same plant to grow as the one you harvested seed from. Most dahlia are the result of hybridizing so their seed won't grow "true". One thing to keep in mind if you are looking for a cost effective way to increase your stock of dahlias, they are easily divided when you dig them up at season's end. Notice that the buds emerge from the base of the old stem. Slice through the stem vertically with a sharp knife, making sure each piece of root has part of the stem attached and at least one eye. You can also propagate dahlia by stem cuttings. Let us know if you would like more information on that by posting another question at the website.
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