Although the red poppy may look a lot like the variety used to produce opium, it is quite legal to plant in California. In fact, the red poppy is quite well suited to grow in the Californian climate. And although it is technically an annual, California red poppy gardeners will find that its seeds self-sow and the blooms will come back year after year. Plant your red poppy seeds in early spring, past the last frost date in Northern California.
Prepare the planting site. California is known for its blazing summer sun. And your red poppies will need a little big of protection from it. The best spot for planting red poppies is one that receives partial shade. Once you have chosen a spot, loosen the soil to a depth of 6 inches. Use a hand or roto tiller to dig the soil up and turn it over. Break up any large clumps of dirt that you encounter and remove any rocks, old roots or other debris that you find along the way. Then rake the planting bed smooth.
Hand broadcast your poppy seeds over the planting area. This is not an exact science, but try to make sure that seeds have at least a centimeter's space between them. Then lightly pat the seeds down with your hand. But do not cover them with soil. Poppy seeds need sunlight to germinate.
Water the planting area. Lightly spray the soil so that it is moist a few inches deep, but not soaking.