Growing lilies as well as relatives like Nomocharis and Notholirion is on going in my propagating area every year. I would strongly advise people who want to grow these plants from seed never to prick them on but eventually plant the whole pot out. I have a lot of nice species mixed in with Meconopsis which complement each other. I am now able to harvest my own seed and hence can sow several pots full of each species each year. An easy species like Lilium formanosanum will sometimes flower in the second year, a few things in their 3rd year, more likely 4th and Cardiocrinums can take up to 9 years to produce a flowering spike (which then dies) but is usually surrounded by offsets which  keep the flowering going almost indefinitely. Favorite species are L. macklinae, L. flavum, L. oxypetalum and L.o. insigne (though I suspect these last two are actually different species). If you use seed exchanges,Notholirion, this image shows Nomocharis hybrids, Lilium macklinae, Lilium oxtpetalum and the white Chinese Lily L. duchartrei. 

you will be lucky to get more than 2 or 3 viable seeds but once you have a stock they can be maintained by growing from seed indefinitely.
The round pot left is Notholirion 2 years old and the large square pot right is 3 year old Nomocharis hybrids - the seed came from the wonderful Explorers garden in Pitlochry (down by the theatre) expertly run by Julia Cordingley. The seed in the front centre that has just germinated is L. oxypetalum insigne. This pot is clearly crowded and next spring will be carefully knocked out with no disturbance and placed in a large pot of rich compost. In an overcrowded pot the fittest will survive and when planted out as many as ten spikes may be produced once they flower.