74-77F is optimum. soiless is recommended, but they will do fine in others. They do require light to germinate and they typically take around two weeks to do so. You don't want the mix/soil to dry completely out, but don't keep water logged either. After the initial soaking when I sow them, I usually bottom water. The condensation on the covering means they have enough moisture.

Thanks for your reply. The only thing I have an issue with is that all the planting instructions I have read say they need to start in darkness. So I am confused. I checked several references. But I assume you have propagated them as you say. Thank you.

I found very detailed instructions at this site http://www.ag.auburn.edu/hort/landscape/Vinca.htm It seems high heat is critical for germination as well as not too much water. I would still like to see home gardener's experience. Thank you Marie

I put them under lights....

But I found this link that might be helpful as well.

Here is a link that might be useful: Aces Publication on Vinca

I'm happy to report I gathered seed from my vinca plants (and many others)last fall. Started them about five weeks ago and they are all doing well. This is only my second year of starting seeds. Thru the winter, I collect food containers (Chinese takeout, plastic sandwich containers, pie/cake containers)with lids. I just put about one to one 1/2 inches of seed starting soil in the bottom of the containers, and water well. Then, I sprinkle my seeds over that. I follow-up with a light covering of my soil and pop the lids on. Some containers I put a plastic bag over if it didn't have a lid. All my seeds come up. Even those that take two weeks or more to germinate, I never open to water. Once they have a true set of leaves, I take the lids off and put under the grow lights or in direct sun. And, I watch them daily for watering needs. Then, I transplant when they get a little bigger into larger containers. I'm so proud of my vincas and I hope I can keep their momentum going. They are one of my favorites! Good luck.