Cardoon will be inedible when grown under hot conditions due to the strong bitter compounds that form. SOIL Cardoon is a perennial plant that will grow on a wide range of soils, but it produces best on a deep, fertile, well-drained soil. The plant is deep rooted and should be planted on soils that afford adequate area for root development. Steady, uniform growth throughout its entire growth period is important for good quality product. Production is best when transplants are grown and set out in spring, but direct seeding may also be used.
Cardoon is sensitive to frost.
Direct seed in the field in early to mid May and thin to a final stand. Seed or transplant into an 8 to 10-inch deep trench and cover seed with about 1 inch of soil. As plants grow additional soil is added untill the trench is filled. Like artichokes, cardoon may also be propagated from stem pieces or suckers that develop off the main stem. Leaves and stalks become pithy when subjected to water stress, making them unmarketable.