The Iceland poppy is a cool weather annual flower that is best grown from seeds planted directly in your garden. Sow seeds in early spring as soon as the soil can be worked. They produce thin, paper-like flowers that are semi-transparent, which gives them the appearance of being brighter than they really are.
Determine the best location for your Iceland poppies. The plants require a site in full sun that gets at least six hours of sunlight per day. They like soil that is sandy, but will also grow in soils on the clay side.
Prepare the seedbed in very early spring, as soon as the soil can be worked. Gently squeeze a handful of soil in your hand, then open your hand. If the soil stays together but breaks apart when you poke it with your finger, it is ready to work. If it turns into hard, wet, mush, it is still too wet; wait a few days and test again. Turn over the soil with a shovel to loosen its texture. Rake it smooth.
Sow seeds. Broadcast the seeds on the surface of the prepared seedbed. Cover with a thin layer of peat moss or vermiculite. Mist the seedbed with a fine mist from a hose end sprayer. Check daily and mist as needed to keep the soil moist until germination occurs in about seven days.
Thin the seedlings when they are 2 to 3 inches high so they stand 4 to 6 inches apart.
Mulch the soil in the seedbed with 2 to 4 inches of unfinished compost or shredded leaves.
Remove faded flowers to prolong the blooming season. Iceland poppies stop blooming when hot summer weather arrives, but will produce lots of flowers before then if you remove the faded ones.