Winter sowing

I live in Concord NH,and wondering when I could start this. We have virtually no snow. And everything is froze hard as a rock.So there is no insulation Thanks for any help

You can start your seed indoors anytime now, Nanners....outside sowing for poppies & larkspur beginning of April....other, less hardy plants, not until May.....

I am pretty sure you can winter sow now if using milk jug method

There is actually a winter sowing forum
http://davesgarden.com/community/forums/f/coldsow/all/

All the pictures I have seen have the jugs with snow all around them, so I assumed it was needed for insulation when you get this far north if I needed the snow

most info I read has nothing to do with snow itself just the temps

http://www.agardenforthehouse.com/2012/01/what-to-winter-sow-and-when/

jen is correct - it is the temps not the snow - i have done the plastic milk jug method for the past few years with success