Artichoke Seeds - Green Globe

Artichokes are a vegetable that originated in the Mediterranean region and are grown for their large, succulent flower buds. An artichoke “heart” is the most tender part of the flower bud, but the fleshy parts of the scales surrounding the heart can be eaten as well. This plant is a short-lived perennial in zones 7 and higher, but can be grown as an annual as far north as zone 3. It needs well-drained, rich soil, and cool (but not freezing) spring temperatures.

Start artichoke seeds indoors 8-10 weeks before the last frost. Germination can be improved by soaking the seeds in water overnight before planting. Keep the seed trays warm and make sure the seedlings receive plenty of bright light. Transplant the seedlings into the garden after the danger of frost has passed, but while days are still cool. Artichokes need a period of about 10 days with temperatures at or below 50 degrees F to trigger flowering. They will not survive freezing though, so make sure to cover the plants if a surprise late frost occurs. Space transplants about 3-4 feet apart in rows at least 4 feet apart - they will grow into sizable bushy plants about 3-5 feet tall. Artichokes are heavy feeders so mix in plenty of compost before planting, and feed every 2 weeks with a balanced organic fertilizer during the season. Excessive heat and drought can cause the plants to produce undersized and tough blossoms, so make sure to keep the soil moist.

Harvest artichokes when the flower heads are full but have not started to open yet by cutting the stem at the base of the flower with pruning shears. The plants are prickly, so wearing gloves and long sleeves is a good idea.

Artichoke plants will go dormant in hot weather, but may produce a second crop in the fall. If you are growing in a zone where artichokes are hardy, cut back the plants and mulch with a heavy layer of straw before the first frost to protect them for the winter. Perennial artichokes will begin to put out side shoots from the main plant in the second year and these can be divided from the main plant and used to propagate more plants, if desired.

If artichoke flower heads are left on the plant, they will open into large thistle-like blossoms. In about 60 days after pollination, the bracts (spiky parts surrounding the flower) will begin to turn brown and silvery-gray pappi (fluffy projections like on dandelion seeds) will begin to emerge from the top of the flower. At this point, the heads can be cut off and brought inside to finish drying. When the flowers are entirely crunchy and brown, break them open (wear gloves, they’re spiky!), pull the seeds out and separate each one from its pappus. 

Artichokes are insect-pollinated so they need to be isolated from artichokes of a different variety  by 800 feet to a half-mile to be sure the seed is pure. Artichokes can also cross-pollinate with cardoon. In some areas of California and the Southwest, there may be naturalized cardoon or artichoke in the environment, so pay attention to what’s blooming in the wild near your garden.