CULTIVATION OF SEEDS OF HERBS AND MEDICINAL PLANTS
Herbs and medicinal plants are usually easy to grow seeds from, but the growing season in northern Europe is often too short. They need the protection of greenhouses, forcing beds or cloth covers to have time to make ripe seeds. The cross-fertilization risks are usually small.
Harvest the flower stems when they have withered and the seeds have the right colour for ripeness. Hang them up and allow them to continue drying indoors. Put a cloth beneath them or tie a piece of fibre-cloth around the heads to collect tumbling seeds. Shake and rub the seeds off and remove the rubbish by sieving and winnowing.
Read more about seed-cultivation under Grow your own seeds