The climate in this part of the world (eastern Ontario) is not very conducive to veggie growing in winter time unless perhaps you had a heated greenhouse (and a thick wallet). However, there's one veggie that's probably not that well-known in these parts, called 'witlof' (Dutch or Flemish for 'white leaf'), that can be produced indoors in the winter time. The plants are first grown outdoors during summer, then the roots are harvested and allowed to 'rest' for a week or 2 before being planted under the soil in a cool location. I have a 1 cubic metre bin in the basement where I force witlof. Once the white tips of the leaves appear about 6 weeks after planting, they're harvested - the roots are recycled via the compost bin (for more info see http://www.jetfresh.com.au/witlof.html).