From looking at the map, looks like Carmel is zone 5- is that right? I'm in zone 6, so a little warmer, probably a couple of weeks ahead of your area where spring thaw is concerned. I guess Dianthus would say we're about a week ahead, LOL.
Lets see, easy ones would be Hollyhocks, Malva, Mexican Hat (Ratibida columnifera), English Wallflower, Bachelor Buttons, Nigella, Chinese Forget me not (Cynoglossum amabile), Calendula, Alyssum, and Rudbeckia. Those are all extra hardy, and you don't have to worry about covering them once they've germinated and you get cold spells.
Digitalis are reliable wintersown, but are very tiny when they emerge, and you need to watch them closely for moisture. I've found Penstemons to wintersow easily too. Columbine wintersow easily, but have a habit of germinating sporadically- the fresher the seed, the quicker they'll sprout. Older seed can take considerably longer, I've had some germinate up into June. I've found wintersowing beats the heck out of other methods for Columbine. Hardy Geraniums wintersow exceptionally well; I've read about folks refrigerating pots of sown seeds for a few weeks, taking them out into warmth for a couple of weeks, sometimes even returning them to the fridg (I've done it before too!). But when I realized all that effort was to simulate what's going on outside, I was like "duh..", LOL. I've wintersown about 6 different hardy Geraniums with ease.
Can't say that I've found anything to be particularly challenging, seems most of the problems I've had have been my error in letting something dry out or pests, like slugs. But there again, that was my mistake by moving the jugs from the deck to right on the ground where slugs slither.
What all have you wintersown, and when did you sow them?
