Worldwide, there are more than 7,500 known varieties, 100 of which are grown commercially in the US. They all differ in shape, size, color, texture, aroma and flavor.

Carrots come in all shades of purple, red, white, yellow and of course, orange. If they have the greens attached, look for feathery, perky leaves with no wilting, black spots or yellowing.

Also known as celeriac, this turnip-sized bulb grows underground. Look for a firm, apple-sized celery root with no soft or squishy spots.

Look for leaves that are dry and free of dark green goop. No yellowing or wilted leaves, which are signs of decay.

Collards are a versatile and delicious member of the brassica family, and can be used both cooked and raw. Look for firm leaves and stems with no yellowing, spots or wilted leaves.

Fennel bulbs should be whitish-green, firm and heavy for their size, with no brown or mushy spots. If the feathery green fronds are still attached, they should have no signs of wilting or dryness.

Horseradish is a large and tapering root with a dark brown peel and creamy interior. Look for firm roots with no mushy or black spots.

Both the root and leafy greens of kohlrabi are edible. The bulb should be firm with no spongy bits and no visible brown spots.

This wild-foraged leafy green packs a nutritional punch with lots of protein, fiber, omega fatty acids and Vitamins A and C. Look for leaves that are perky.

Common leeks look like giant scallions and have a mild onion-y, sweet flavor. Look for leeks on the smaller side, 1-2" in stem diameter with very dark greens that have no yellowing or wilted spots.

Used both in cooking and herbal medicine, mint should have perky stems and leaves with no black spots or wilted parts. Fresh mint should also be very aromatic.

Oregano and marjoram are both available as fresh or dried herbs. To preserve freshness, store dried herbs in a cool, dry place and store fresh herbs in the refrigerator.

Parsley is available in both curly and flat-leaf varieties. For both, look for firm, perky leaves, firm stems and no wilting or yellowing of any kind.

Peanuts can often be purchased in their distinctive, textured shell either dry roasted or roasted in oil. Be sure to store peanuts in a cool, dry place and discard any peanuts that show signs of mold.

Purslane has the most omega-3 fatty acids of any green vegetable. Its flavor is slightly tart and a bit lemony - perfect for summer salads.

With its distinctive smell, sage adds a savory note to many dishes. Look for sage that has perky, silvery green leaves and a strong smell, avoiding any withered or dry leaves.

Salsify is a slender woody root, with light brown or black skin and white flesh. White salsify is said to be similar to oysters in flavor.

Sorrel comes in both red and green varieties, but both resemble spinach. Sorrel has a sharp, tart, green apple taste that adds a tang to salads and cooked greens.

Fresh spinach leaves can be sold as loose leaves or still attached to the stem. Look for perky, evenly colored leaves with no mushy spots. Smaller leaves will be the most tender while larger leaves can be stringy in texture.

Although you can sprout many seeds, the two most common sprouted types are bean and alfalfa. Look for sprouts that are perky and smell fresh. Avoid any that smell off or that appear slimy or wilted.

Sometimes called Jerusalem artichokes, sunchokes are the roots of a native North American plant in the sunflower family. Look for roots that are firm to the touch, with no spongy or mushy areas.

Nutritional powerhouses, sweet potatoes come in an array of shapes and colors. Look for sweet potatoes without dark blemishes or soft, discolored areas.

Winter squash is actually harvested in autumn before a hard frost and stored for later. Squash comes in many sizes and colors and may even have decorative warts. Avoid squash with visibly broken skin.