It's most likely the temperature swings. I had trouble with the colored ones, but the old-fashioned ones (may have been perennial ones worked ok. My they were little. Isn't it early to start them where you are at?

Yes, definitely early, but i'm trying to figure out how to keep a consistent supply through the season. I was hoping to put them in the greenhouse in pots for the early blooms, then sow some outside when it warms up.

Get the perennial kind. Hubby's aunt started out with just for herself. Then she started supplying for a florist. Plus I found the perennial kind is easier to start. Check with the winter sowing forum, it makes it start when the weather is right, and alot easier.

Good advice - I'll pick up a packet of the perennial type.

its early enough, try again and keep some of them cooler and some of them hotter. then you'll know.
if your house gets down to 55, then put them on the heat mat at night, maybe? do make sure they're uncovered or at least the germination domes propped up to let heat out during the day or you'll fry them for sure.

Sandy I tried both annual and perennial, the annual died off, while the perennial. They just dried up and died. had plenty of water. In same tray on opposite sides of rib.

Now I'm going to have to try it...I love a challenge!