Opium Poppy Seeds Not Germinating

I sowed seeds of Papaver somniferum var. nigrum a couple of weeks ago and haven't seen any signs of life yet. They were sown onto a sterile medium, very lightly covered and kept evenly moist. Any suggestions? (Sorry, I didn't order these from you and there were no sowing instructions).

Opium poppy (Papaver somniferum) is a quick germinator. The seedlings should be up within a few days, no more than 7 days. Richters opium poppy seeds are germinating very well, over 90%.
There are many reasons why seeds may not perform. Poppy seeds are quite small and inexperienced gardeners can easily plant them too deeply. When planting in seed flats or boxes, never plant deeper than 2-3 times the diameter of the seeds themselves. Of course, if the seed box dried out anytime during the germination process, seedlings could be dead before they appear.
If all the right conditions have been provided, then you must suspect the seeds themselves. If you have leftover seeds you should try a second sowing.