I plan to do raised beds & try heirloom seeds...was wondering if I could make a type of 'cold frame' over my raised beds & start seeds there instead of starting inside & moving.
Thanks,
Linda in Ponder

The soil temperature is the big factor to consider in this. I think you'd be better off starting them indoors and moving them outside when the soil truly warms. I'm afraid your frame wouldn't be robust enough to somehow warm the soil deep enough to keep the tomatoes happy.