I'd like to start my seedlings really early next spring, but I don't have
much room indoors. I'm going to set up a wood-frame and plastic tarp
enclosure outside. I realize I'll have to get the seedlings to sprout
indoors, and then I'll move the trays out to the enclosure asap.

Any advice on this? How early can I start this? Will the seedlings continue
to grow when it's really still quite cold outside?

I'm in s/w BC (zone 8). Pacific Northwest for Americans. The temp only
occasionally goes below freezing in winter, generally hovers in the 40's.
Comments?