A few ideas on storage and cooking:
Kohlrabi — they look like sputnik, but they taste like a cross between cabbage and turnips. Take off the leaves if you’re going to save them for a few days. Peel the hard outer skin before using in a recipe — they’re good sliced raw into a salad or roasted with root veggies, added to soups or sauteed in butter on their own.
Rutabaga — Will keep in the crisper very well. Try smaller ones raw with sliced cheese, or add to a mash with your potatoes.
Mustard and Collards — the bitter greens can be a bit intimidating, but they’re extremely good for you. They look like a huge volume, but they shrink a lot when cooked. Fat and acid will cut the bitterness if your family isn’t a fan of the strong tastes. Tonight I used up two bunches of mustard greens in a simple side dish for rice and curried chicken. Simmer one can coconut milk, garlic, a bit of stock, salt, and pepper with shredded mustard greens until tender, about 20 minutes.