Autumn sowing in pots or compressed peat pellets avoids root disturbance. Spring is the time for direct sowing and thinning but I am going to risk some over wintering of direct autumn sown plants.

Soil Preparation
Poppies like deep, well-drained, fertile soil in full sun.
Feed the soil with manure or bone meal ahead of planting.
Poppy somniferums grow quickly given sufficient water and a nitrogen rich soil. to increase both the number of flowers and their individual size. Although these poppies gobble up the nutrients, their eventual show will be more than worth the proper environment.

Sowing
Seeds should germinate in less than two weeks and seedlings will appear approx 6 later.
Keep moist at all times,
Sow covered lightly directly in spring where they are to flower using short drills.
Mark and label but after planting they can be told from nearby weed seedlings quite easily.

Cultivation
Thin the seedlings out 12in apart by early summer. Be ruthless, just leave the biggest and most healthy looking. By doing this, you’ll get more flowers and pods per plant that are bigger and stronger.
Poppies don’t need to be watered too often, but when you do water, give it a nice soaking. This will promote strong root growth.
After about 6 to 8 weeks of vegetative growth, add a high Phosphorus fertilizer for the flowering stage.
The most serious problem for these poppies is root rot if the soil is too wet.
A slug and snail deterrent is recommended.

More poppy seeds at Thompson & Morgan

The seeds of this poppy can be used in cooking and is often found on bread loaves. Only seeds produced by somniferum and paeoniflorum poppies are edible, other varieties can be poisonous.