Using a perennial's own seeds for replanting
Plant seeds of the Iceland poppy plant in fall. Seed directly into the flower bed that will be the permanent location of the Iceland poppy flower, as growing Iceland poppies do not transplant well. There is no need to cover the seeds; the Iceland poppy plant needs light to germinate in spring, just make sure their are in firm contact with the soi.. Mark the area,, so you don’t mistake the spring foliage for a weed. Full sun area. Soil for the Iceland poppy plant should be light and well drained.
Read more at Gardening Know How: Iceland Poppy Care – How To Grow An Iceland Poppy Flower https://www.gardeningknowhow.com/ornamental/flowers/poppy/growing-iceland-poppies.htm
Thank you for your response. However, it did not answer my question. I would like to know if the deadheaded seeds could be used, after drying, to be planted for new poppies instead of store-bought seeds.