These long-season plants native to the Mediterranean region won’t overwinter reliably north of Zone 7. To get a crop of artichokes in one year, start seeds indoors in pots 2-3 months before last frost date in spring. Move the pots outdoors when four leaves have developed and temperatures are occasionally freezing, protecting them if temps fall below below 29 degrees. Two to four weeks of exposure to cool temps “vernalizes” young seedlings, preparing them to bloom later in the season after plants have grown large. Cardoon may also be started early indoors, but vernalizing isn’t necessary. Both kinds are then grown on in very rich soil, in full sun. They need excellent drainage but ample moisture. They may benefit from some mid-afternoon shade in hot summer areas.