Poppies germinate within 10 to 15 days when soil temperatures reach 55 degrees Fahrenheit. However, poppies are cold hardy; brief dips into low temperatures or late spring frosts don't generally affect them. Plant poppy seeds when the soil is workable in your region.
You may plant poppy seeds in the fall in USDA Zone 7 and above. They may bloom earlier the following season than spring-planted poppies, as long as they receive adequate sunlight. Do not plant poppies in the heat of the summer, as even mature plants become dormant.
Poppy seeds are relatively small, making proper spacing difficult. Scattering pure seed results in overplanting and clumps of tiny sprouts. Instead, mix one part seed with four parts sand before casting over the site. After planting, lightly rake the bed or dust the area with soil; poppy seeds germinate best with shallow cover.