100 Organic White Afghan Poppy Seeds Papaver Somniferum Plan your poppy garden for an area that receives full sun. Plant seeds in early spring or after the last snowfall for an early summer showing. For late spring blooms, sow seeds in early autumn. .Loosen the soil using a tiller, hoe, spade or rake. Spread a light covering of compost or organic fertilizer, and rake to distribute it evenly.