Collect seed heads from globe thistle plants in the fall, and remove seeds. You can sow outdoors, where germination will occur naturally in the spring. If starting indoors, stratify seeds in the refrigerator for best germination. Use large cell packs to accommodate the long taproots that begin to form after germination.

Growing globe thistle from collected seeds is imprecise, but purchased cultivated seed has a better seedling rate. The plants also often self-seed. Growing globe thistle from clump division is the fastest way to get flowers. Divide the basal growth away in spring from plants that are at least 3 years old.