Green Globe Artichoke Plants
The Green Globe Improved artichoke is a perennial heirloom variety with silvery-green leaves. Hardy in USDA zones 8 to 11, green globe artichoke plants require a long growing season. When started indoors, they can be grown as annuals in colder climates. Green Globe artichoke plants grow to height of 4 feet (1 m.). The flower bud, the edible part of the artichoke plant, develops on a tall stem from the center of the plant. Green Globe artichoke plants produce three to four buds, which are 2 to 5 inches (5-13 cm.) in diameter. If the artichoke bud is not harvested, it will open into an attractive purple thistle-like flower.
How to Plant Green Globe Artichoke Perennials
Green Globe Improved artichoke plants require a 120 day growing season, so direct sowing of seed in the spring is not recommended. Instead, start plants indoors between late January and early March. Use a 3 or 4 inch (8-10 cm.) planter and a nutrient-rich soil. Artichokes are slow to germinate, so allow three to four weeks for the seeds to sprout. Warm temperatures in the range of 70 to 75 degrees F. (21-24 C.) and slightly moist soil improves germination. Once sprouted, keep the soil moist but not soggy. Artichokes are heavy feeders too, so it’s advisable to begin weekly applications with a diluted fertilizer solution. Once the seedlings are three to four weeks old, cull the weakest artichoke plants, leaving only one per pot. When the seedlings are ready for transplant into perennial beds, select a sunny location which has good drainage and rich, fertile soil. Prior to planting, test the soil and amend if necessary. Green Globe Improved artichoke plants prefer a soil pH between 6.5 to 7.5. When planting, space perennial artichoke plants a minimum of 4 feet (1 m.) apart. Green Globe artichoke care is fairly simple. Perennial plants do best with yearly applications of organic compost and a balanced fertilizer during the growing season. To overwinter in areas which receive frost, cut back artichoke plants and protect the crowns with a thick layer of mulch or straw. The Green Globe variety continues to be productive for five years or more.
Growing Green Globe Artichokes as Annuals
In hardiness zones 7 and colder, Green Globe artichoke plants can be grown as garden annuals. Start seedlings as directed above. It’s best to transplant artichoke seedlings into the garden after danger of frost, but don’t hold off too long. To ensure blossoming the first year, artichokes need exposure to temperatures below 50 degrees F. (10 C.) for a minimum of ten days to two weeks. If an unexpected late frost is in the forecast, be sure to use frost blankets or row covers to protect artichoke plants. Green Globe Improved artichokes also make excellent container plants, giving northern gardeners another option for growing artichokes. To grow a perennial potted artichoke, trim the plant 8 to 10 inches (20-25 cm.) above the soil line in the fall after harvesting is complete, but before freezing temperatures arrive. Store the pots indoors where winter temperatures remain above 25 degrees F. (-4 C.). Plants can be moved outdoors once frost-free spring weather has arrived.
