- You will get 120 Seeds of Purple Romagna Artichoke Heirloom Vegetable Seeds. - Sunlight: Full Sun. - Life Cycle: Biennial. - Watering: Light. - Purple Romagna Artichoke Seeds!. - The artichoke is a cultivated thistle grown for its edible flower buds, which are either green or purple and must be harvested before the flower begins to bloom. Plants are mostly perennial, although some types can be grown as annuals (particularly above zone 7) , and will reach 2?7? tall with silvery to green leaves. Flower buds grow 3?6? in diameter with spiny scales. Both the base of the bud and the fleshy lower half of each scale can be eaten. Plants will produce numerous buds, particularly if harvested regularly. - Artichokes do best in cool weather and are usually planted indoors and transplanted outdoors. They grow best in humid areas where temperature remains below 50 F for a long period of time. Start seeds indoors 6 to 8 weeks before setting outdoors. Plants require 50 F to 70 F temperatures to induce budding. Spring planting should occur as soon as soil can be worked and after last frost, and fall planting done in September, October, and November for spring harvest. When seedlings are 2" to 4" tall, transplant them into larger pots so roots can grow properly. Protect the plants from frost. Plants become less productive in 5th and 6th year and new plants should be grown. Plants can grow 3 to 5 ft tall. - 1/4 to 1/2" Planting depth. - 70 F to 80 F Germination temp. - 10 to 21 days to germination. - Full Sun. - Spring/Fall.