A green artichoke specifically bred for annual production, Imperial Star will produce well-developed artichokes the first year from seed. Plants become 1 1/2-3' tall and have an open growth habit. Each typically produces 1-2 primary buds, which average 3-4" in diameter, and 5-7 smaller secondary buds. Perennial in Zone 7 and warmer; otherwise treat as an annual. Avg. 10,000 seeds/lb. Packet: 25 seeds.
CULTURE: Artichokes and Cardoon require very fertile, well-drained soils in a pH range of 6.5-8.0. Sow Artichokes indoors 8-12 weeks before last spring frost date. Cardoon is more vigorous and can be started later, 6-8 weeks prior to last frost date. Sow 1/4" apart and 1/4" deep in 20-row or open flats. Germinate at 70-80°F (21-26°C). As soon as seedlings can be handled, transplant to 4" pots or 1½" cell-type containers and grow at 60-70°F (15-21°C) day and 50-60°F (10-15°C) night. Transplant 6- to 12-week-old plants to the field 2-3' apart in rows 4-6' apart. Perennial to Zone 6, otherwise, treat as an annual. See specific requirements for each species below. GLOBE ARTICHOKES: IMPORTANT COLD TREATMENT (VERNALIZATION): Time transplanting so plants receive 10 days of 45-50°F (7.2-10°C) temperatures to induce earlier budding. Protect from frost. HARVEST: Clip mature buds mid-summer to mid-fall, depending on location. MILD AREAS: Where winter low is above 14°F (-10°C), sow seeds in fall, harvest in spring. SEED SPECS: SEEDS/LB.: Avg. 9,650. CARDOON: BLANCHING: Gather stalks in late summer or early fall, tie upright with twine, and wrap with black plastic or black and white newspaper to exclude sunlight. Blanching is done for 3-4 weeks during the cooler weather of early fall. HARVEST: Harvest after blanching, cutting at the base of the stalks to keep intact. SEED SPECS: SEEDS/LB.: Avg. 12,350. PACKET: 25 seeds unless otherwise noted.