Occasionally I get asked if I could grow other crops besides salad greens. Of course other fruits and vegetables can be grown in greenhouses, but most of them require things that I can't provide. Like extra lights, actual warm temperatures (the 40 degree greenhouse is pretty cold!) and way more space. Most crops grown for their flowers (broccoli), roots (carrots, beets) or fruits (tomatoes, cucumbers, squash) all need more soil and space to grown than mere salad greens. So, it would be better to grow them in the ground, or in giant buckets on the ground, than on top of greenhouse benches.
Radishes are the one crop I've thought of, and tried growing like salad greens. They are in the brassica family (as most wintergreens seem to be) and are crunchy but not yet spicy. The spice will come with age. I think they are a variety called 'crunchy royale' and they only took a month to get this big. The leaves are edible, but are a bit prickly so I prefer not to eat them raw.