Seeds develop in the plants flowers. The flowers are harvested and completely dried. Once dried the seeds can be picked out manually one by one or they can be crushed and separated by hand. It takes a really long time to manually separate seeds from the flower. Its really not an enjoyable process. I designed and built a seed separating machine that uses suction to separate flower debris from seeds. The seed separator is made out of PVC and ABS pipe and fittings, only took 30 minutes to assemble and cost under $40.