Be sure to be aware of all the creatures that will ruin your poppy growing experience. Birds, for one, like to eat poppy seeds. So you may need protect against them.
TUTORIAL: How to Grow Somniferum Poppies – Part II
Some people prefer to start them indoors under lights, but be sure to start them in Peat Pellets, as poppies do not transplant well because they have very sensitive root systems and one very long Tap Root that can be damaged easily; killing the plant.
But once they sprout, you should put down some Slug Bait. Slugs love to eat tender, young seedlings. I suggest using SLUGGO because the active ingredient is iron phosphate, which is completely harmless to pets and animals, and remains even after it rains.