You can tell the difference between greens by looking at them. Collard greens have very large leaves compared to other greens. They have large stalks running through them and veins throughout the leaves. Mustard greens have smaller leaves than collards. The edges of mustard greens are ruffled. The leaves of turnip greens are less defined and are slimmer and longer than those of collards and mustard greens. Spinach leaves are very small compared to the leaves of the other greens. All of these greens are about the same color.
The taste of different greens are very distinctive. Some greens can be eaten raw, but turnip greens are the most bitter of all of the greens. Turnip greens are best when picked and eaten when the plants are young. Mustard greens have a stronger flavor than collard greens and spinach. Mustard greens are best when the plants are between five and 12 inches high. Spinach is the mildest of these greens. Spinach is so mild that is it often eaten raw.
Dark, leafy greens have great nutritional value. Collards, mustard greens and turnip greens are an excellent source of folate, vitamin C, calcium and beta carotine. Spinach is rich in beta-carotine, lutein and zeaxanthin. Collards, mustard greens, turnip greens and spinach are also good sources of iron and magnesium. Lutein and zeaxanthin help protect against cataracts and macular degeneration. Greens provide some fiber and are filling. They have few calories and help fight fat.
All greens should be washed and large stems should be removed before cooking. Boil greens in water. Cooking times vary between the different types. Collard leaves can be stacked on top of each other. Roll the leaves up like a tube. Cut collards into strips. Mustard greens can be put directly into pot after washing. If you are cooking turnips with the greens, it is best to bring the turnips to a boil before you place the greens in the pan. Spinach takes less time to cook than the other greens. Cook all greens until tender.