Artichokes
Season: Available throughout most of the year, springtime is high season when all sizes are widely available.
What to look for: Artichokes with leaves that are tight, compact, and bright green.
What to feel for: Give an artichoke a squeeze, its leaves should squeak as they rub together (evidence that the artichoke still possesses its moisture).
Beets
Season: Beets, both with and without their greens, are available year round.
What to look for: Choose medium-size beets for the best return on investment (small beets are harder to prep and peel; very large beets can be woody). Beet greens attached to beetroots is a sign of freshness.
Kohlrabi
What to look for: Smaller bulbs, about the size of an orange (grapefruit size kohlrabi is likely to be spongy or woody). Whether green or purple, the color should be vibrant and free of blemishes.
Store: If you purchase kohlrabi with the stalks and leaves attached, separate them before storing them both in loosely closed plastic bags in the refrigerator. Bulbs will stay fresh for a week or longer; the greens will keep for several days.
Fennel
What to look for: Sometimes labeled as "fresh anise" in the supermarket, look for bulbs that firm and creamy white, with as little discoloration or brownish spots as possible. The stalks should be crisp and firm, and the fronds should be feathery and bright green.
Store: Place fennel in an open plastic produce bag and place in the fridge for up to a week.