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.

Like most tender greens, arugula is perishable and needs to be used within a few days of purchase. Look for crisp leaves without mushiness.

Bok choy (or pok choi) stalks should be firm and blemish-free, with nothing bruised or mushy. Leaves should be perky and green, with no brown or yellow spots.

Cardoons are sold in large bunches that look a lot like spiky, silvery celery. Stalks should be firm with no spongy or blackened spots.

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.

Look for an even color and a tightly packed head. Apart from its standard white, cauliflower also comes in purple, orange and green varieties.

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

Also known as Swiss chard or rainbow chard, you can eat both the leaves and stems. You want crisp, perky and glossy leaves, with firm and healthy stems.

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.

Mature garlic heads should have a paper-like skin that covers all the cloves, which ideally are firm and free of mold or bruises. Green garlic has a light green stalk and white bulb at the base with darker green tops.

Whether you call them green onions, spring onions or scallions, these alliums all offer a slightly milder taste than their onion cousins.

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.

When shopping for kale, stay clear of wilted or browning leaves. Leaves and stalks should be firm and dry instead of wilted and mushy.

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.

There are several varieties of mushrooms and they can be purchased fresh or dried. Look for fresh mushrooms without slimy, moldy or black spots.

Mustard greens are peppery, leafy greens in the same family as broccoli and kale. Look for perky greens that are not wilted with no mushy or black spots.

Okra pods should be firm and springy with no mushy, brown or yellowing spots. Cooks agree that the perfect pod size is four to five inches long.

When purchasing dried onions, avoid brown or mushy spots and choose onions that feel heavy for their size without any signs of sprouting.

Parsnips are a root vegetable that look like a pale carrot, usually a shade of pale yellow or ivory. Look for parsnips that are firm but not tough.

No matter the variety of potato, be sure to store them in a cool, dark place with low humidity where they can be stored at least one month and up to three months.

While pumpkins come in a variety of types, sizes and colors - you should always choose a pumpkin that feels heavy for its weight and pass on those with any black or mushy spots.

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.

Rapini, or broccoli rabe, looks like a leafier version of broccoli. Both the leaves and florets should be deep green without yellow spots.

The rutabaga is a sweet root vegetable that looks a lot like a large turnip with pale yellow flesh. Rutabagas are often sold with a protective layer of wax that improves shelf life, so peel them before cooking.

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.

With their delicate, sweet flavor, shallots look like small red onions. When buying shallots, make sure to feel under the papery husks to make sure the bulbs feel firm.

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.

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.

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

Sweeter and milder than their larger counterparts, baby turnips are perfect for eating raw, roasting or tossing in salads. Turnips should be firm with tight skin. Avoid any that look wrinkled or withered.

Watercress is a leafy green vegetable with a peppery flavor that pairs really well with duck and other game meats. Try to avoid any mushy leaves, as they can spoil the others in storage.

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.