Despite its tender leaves, spinach is a tough little plant. It overwinters easily in my zone (6b in the Central Oregon high desert) without protection, and bounces back in early spring with renewed vigor.
Previously dismissed as weeds, mache (also known as corn salad or lamb’s lettuce) and miner’s lettuce (also known as winter purslane) are popular with foragers and with four-season farmers looking for a low-maintenance winter crop.
Collard greens are not just a Southern thing. I’ve been cooking with these nutrient-dense greens for decades in soups and sautes; they also make excellent green wraps if you’re tired of tortillas.
The key to getting cabbage to survive through winter is to start the seeds indoors in early to mid-summer (depending on your climate), then transplant in the garden in late summer. This way, the plants will be well established before freezing weather arrives.
Swiss chard is often grown in summer gardens because it has great drought tolerance, but it’s that same trait that makes it remarkably tolerant to cold as well.