Whether grown for the edible flower bud or as a unique, 5′-6′ ornamental, artichoke plants are as beautiful as they are delicious. Artichokes are grown as perennials in USDA zones 7-10 (zone 6 with heavy mulch), and as annuals everywhere else; although some gardeners in cold climates grow artichokes in large pots that get transferred to a protected area, like a garage, during winter. Expect 2-3 primary buds the first year, followed by a flush of 5-7 secondary, smaller buds. Perennial artichokes will bear fruit for 4-5 years, getting larger and more productive as time goes on. If buds are not harvested to eat, they will turn into beautiful, thistle-like, purple flowers-a sight to see! Lovely in large flower arrangements or autumn harvest baskets. Flowers form in late summer, much to the joy of bees, moths, and butterflies.
The trick to getting the yummy vegetable is to start plants early, subjecting them to vernalization (a cold period) of at least 2 weeks growing at 40°-50°F, which triggers flowering later in the season. In USDA zones 7-10, winter can provide natural vernalization, but in colder areas, hardening off and transplanting your seedlings before temperatures warm up (giving them 2 weeks below 50°F but above freezing) will also vernalize your plants. Alternatively, if you have an indoor, temperature-controlled area, growing them between 40°-50°F under grow lights for 2 weeks will also work.
When to sow outside: Cold Climates: Not recommended. Mild Climates: Sow in fall for harvest the following spring.
When to start inside: RECOMMENDED. Cold Climates: Sow 12 weeks before your average last spring frost date. Ideal soil temperature for germination is 70°-80°F.
Use a lightweight, seed-starting mix/media (sterile, and lighter than potting mix), and sow artichoke seeds 1/4″-1/2″ deep in 4″ biodegradable pots to avoid taproot disturbance. Sow 2-3 seeds per 4″ pot.
Thin to the strongest plant once leaves appear (clip extra plants at the soil level using scissors). The strongest plant may not be the tallest; look for thick, strong stems and deep color. Even with careful selection of seed, a small percentage of artichokes may sprout stunted or albino due to their genetic diversity. Clip out these ‘off types’ in the seedling stage too. By thinning early, you minimize the negative impact of crowding, like stretching for light.
Harden off seedlings after four true leaves appear. Hardening off is the 7 to 10 day process of introducing pampered seedlings to the intense, outdoor sun and temperature swings. Read our article for hardening-off instructions. Transplant 4 weeks before average last spring frost, or in mild climates, 6 weeks before average first fall frost. Transplant into rich, well-drained soil, in an area with full sun (6 hours or more, unless extremely hot, then provide some afternoon shade). Be gentle, to avoid disturbing the taproot. Transplant 4′ apart; they do best when they are not crowded. Growth will be slow at first, but pick up once established. Protect tender seedlings from frost.
Optimal Grow Conditions
Rich, well-drained slightly acidic soil.
Artichokes perform best with moderate water; drought can cause premature flowering, while soggy soil can rot roots. They are heavy feeders, and a monthly side dressing of quality, aged compost or balanced fertilizer can be beneficial.
Choose an area with full sun (6 or more hours per day). Protect from intense sun; provide some afternoon shade.
Very heavy feeder. Prepare bed with generous amount of compost. Side dress every 3 to 4 weeks.