Collect the seed when it is truly ripe, let it dry on a paper plate or towel for a few weeks, package, store dry in a cool, dry, dark place (I use those boxes made for storing photos). Come winter, sprinkle in a milk jug that has 3-4 inches of moist seed starter mix (I use pro-mix) and set outside where it will get rain/snow. In the spring when it warms up, you should have some babies in there!

I have found the purple easier to germinate than the white, but get germination on both, just more on the purple.

What about Meringue and Pink Double Delight, do those seed?