Fresh indigo seed can be sown in the fall or stored in the refrigerator for sowing the next spring. For spring sowing, soak the seeds in water for 24-36 hours first (starting with hot water). If you sow Baptisia australis seed in pots, start with 4-inch pots so the seedlings can develop good roots before needing to be transplanted. This is a tap-rooted native perennial does not much enjoy being transplanted. Seedlings can take three or four years before they flower, but after that, baptisia is a reliable, easy-to-grow perennial that can persist for decades.