The moon is right keanl, the good thing about the tuber type though is, you can propagate new plants from the tubers but not always from seed types,
The seed type here in UK are normally used for bedding out late summe and the tuber ones are mostly grown in baskets, tubs or hanging pots, after summer, the frost blackens the foliage on the tuberous type, remove this and you store tuber /in pot or lift tuber for storage indoors over winter, try to keep the tuber as dry as it can be, now (Feb) is the time when I give a little light in daytime but wont begin to water till I see a few little pink/red or white tint buds appear around the indent of the tuber, then water from below by placing the pot tray into a basin of water till the soil changes colour, (darker brown usually means the soil is wet enough. remember to add label and dates, colour ect to the new pot's.
IF at this time you wish to take cuttings, you get ( SHARP) knife or razor blade and cut tuber into sections WITH a bud as described attached. pot on and look after as for the parent plant.
Good luck. WeeNel.