From Ice Age Farmer Wiki
Much like Lettuce, there are some surprisingly hardy heirloom varieties of spinach that can perform quite well throughout winter. Seed Savers Exchange offered eight cold-hardy varieties (2010):
- America, a variety reported to have outperformed all others in an unheated greenhouse over winter in Pennsylvania. In my own garden, the plants suffered from the heat of summer, and not only were slow to grow but also extremely slow to bolt.
- Bloomsdale Long Standing, a small-leafed spinach that overwinters to produce well in spring.
- Bloomsdale Winter, a good fall and winter spinach with dark green leaves.
- Cold Resistant Savoy, resistant to both cold and heat, as well as slow to go to seed, a trait that provides a longer window for harvest.
- Guntmadingen Winter, a rare Swiss heirloom variety that is exceptionally winter hardy. Oak-leaf shaped leaves.
- Haldenstein, another Swiss variety named after a Swiss village that has been keeping this seed line alive since before the First World War. A great fall crop, winter spinach with large leaves.
- Norfolk, overwinters with mulch or some protection for a spring harvest, making it another food that helped to end the hunger gap in the days before industrialized food.
- Verdil, a giant-type spinach that Exchange members report as an excellent producer in winter, even under a foot of snow in Oregon.