This is the time of year when most Meconopsis seed needs harvesting. Here in Scotland it is a late season and the weather is cool and wet. The stems bearing seed pods must not be picked until they have naturally opened the valves at the top of the pod. Then take these whole seed stems and place them on trays to dry. Where there are only a few individual seed pods, these  can be placed in dishes of some sort. Once they are dry (3 or 4 days usually) sieve out any coarse debris and then gently blow away finer stuff and infertile seeds. Fertile Meconopsis seed varies in size with something like Lingholm the largest but all should look round and have some weight. The top picture shows a pod of M. napaulensis hybrid with the valves open and the seed ready to spill out