Whoa there, everything I have read about growing poppies has said they enjoy abuse. Basically a loamy, fast draining, low nute enviroment is best. They thrive in drought conditions. I've read people saying they don't water at all, let the rainfall take care of it.
I know it is in our nature to try to provide everything we think they need as plants but as I read, they do best when almost completely ignored. Sounds strange but my peyote cactus are the same way. low low low nutes and water super infrequently (of course these ARE cactus after all) but poppies are very similar in their water requirements. I've sown some over the winter, more this week and I will sow for the next month. Then starts the thinning. You have to give them some room. When they cluster up they compete. I think it was several centimeters apart but please research. Good luck. I'll post any results I get as well.