Are you sowing indoors or are you winter sowing these?

Tracy

Nasturiums should be direct sown in the grownd. They don't like to have their roots disturbed. They are fast to grow so it shouldn't be a problem - you can also soak the seeds before sowing to speed up germination. If sowing inside, I would only sow the zinnias 4-5 weeks before putting out in the garden (based on your last frost date) or else they will get leggy. You can put the pansies and snapdragons out before the last frost so it is good you have started those. If you are growing marigolds I would sow 4 weeks before the last frost. I tend to like to put out smaller plants so these are the rules I use. I do this partly to prevent leggy, weak plants and not have them root bound.

Try going to the forum for your region. I do believe there is a Great Lakes or Northern such region forum? There, you can get the locals to advise you who are doing the same thing. Make a post something like "looking for garden buddies near [city], MI for advice re seed starting" and they should be able to give you a Spring timetable. From my experience living in zone 6 MA, my last frost was around May 15th. Are you sowing outdoors in situ and/or indoors in a flat? Need to know more. Maybe you are doing both. Email me for my old schedule, as I am now in NC z7, but can still help. It is still too early to do much in z6 indoors without a greenhouse and heated mats, and almost nothing outdoors except for Nigella; cool season annuals which will germinate when ready. Sure, go ahead and sow your Cosmos. They will know when to germinate. Mine in zone 6 MA germinated in April sometime. Hope that helps.