Leek

A fast cool-season annual of the mustard family grown for its peppery, mustard-like salad greens - irregular, pinnately-lobed basal leaves in a low rosette, each with 4 to 10 small lateral lobes and a large terminal lobe (Missouri Botanical Garden). First cultivated by the ancient Greeks and Romans and still widely grown across Europe, it is best grown in the cooler spring and fall months rather than summer heat; leaves are harvested young and tender before they turn strong and bitter. Pale-yellow four-petalled flowers with dark brown or purple veins appear in corymbs if plants are left to bloom.

A cool-season vegetable grown for its large, tight, terminal head of green flower buds on a thick edible stem, framed by waxy blue-green leaves. Grown as an annual; it grows poorly once daytime temperatures consistently exceed 80°F, so it is timed for spring and fall. Harvest promptly while the head is firm and tight, before the buds begin to open.

A slow-growing, long-season cool-weather vegetable grown for the miniature cabbage-like buds (1 to 2 inches wide) that form in the leaf axils along a single 2-3 foot stem. It is the same species as kale, cabbage, broccoli, cauliflower, and kohlrabi, differing only by cultivar group. Flavor improves after the first fall frost, so it is timed for a cool-temperature autumn harvest rather than summer heat.

A cool-weather brassica grown for the large, tight head of aborted white flower buds - the "curd" - that forms at the center of a rosette of broad blue-green leaves. The same species as cabbage, broccoli, kale, Brussels sprouts, and kohlrabi, it is harvested before the curd ever opens into true flowers. Grown as an annual; notoriously fussy, with little tolerance for heat, drought, or cold, it does best in the cool temperatures of spring and fall.

A cool-season root vegetable in the carrot family (Apiaceae) grown for its swollen, edible, brown, turnip-like root, which tastes like celery with an additional turnip-like flavoring. Biennial by nature, it is grown as an annual: in its first season it forms a basal rosette of aromatic, pinnately divided leaves above the enlarging root, and only in a second year would it send up a summer bloom of off-white flowers in umbels. Missouri Botanical Garden PlantFinder describes a plant 2 to 3 feet tall and 12 to 18 inches wide that wants full sun, rich moist well-drained soil, and consistent water. It dislikes summer heat and humidity, growing best between 60 to 75°F, and the root is ready to harvest after 3-4 months.

A cool-season biennial vegetable in the carrot family (Apiaceae), grown as an annual for its crisp, edible ribbed leaf stalks. Apium graveolens is native to temperate Mediterranean Europe, Asia, and Africa - not North America. It demands rich, consistently moist soil and steady cool temperatures (60 to 75°F); heat and drought turn the stalks stringy and bitter, which is why it is one of the more finicky garden vegetables.