Relax. It is extremely likely that the sprouts you have will do just fine. You said you've done mostly perennials up until now? Those should all be fine. If you have tender annuals, it is much less likely that they've sprouted. If they have, you can move them to a warm place, or write them off as a learning experience. If you are going to try to manage 200+ containers, I'd leave everything up to Mother Nature and just try to keep up with the watering and eventual planting out. When planting out comes, you may be glad to have lost a few containers, LOL. But seriously, I don't think you have anything to worry about. Take a deep breath and enjoy the miracle of sprouts. Hugs,

Martha

Lin, Docmom is right, hardiness of the seedlings is what make Winter Sowing so great. Unless your temps drop below 0 degrees, you are good to go!

What you got sprouting?

I don't know what sprouted, unfortunately I put markers inside the containers this year and didn't take the time while I was watering to open them up to read! I was trying to do too many things at once, just ran out every hour or so and switched jugs in and out of the water container, didn't even notice any green until one of the last cycles. I planted 177 varieties of perennials, though, definitely all of the containers that had green were hardy down to zone 4 or 5, maybe I'll still have green when they're uncovered. If so, I'll post what's sprouted.
Our temps went from 65 deg Sunday to a low of 10 last night, supposed to be just as cold and still some blowing snow tonight. I covered the entire lot with several felt lined plastic tablecloths I use as dropcloths for painting; hopefully that will shield them a bit. It's supposed to be back in the 40s by Thurs and 60 again by Saturday, oh the joys of spring in Denver....Hopefully I'll still find some green when I uncover them, probably tomorrow or Thurs.