Even though poppies grow easily when sown directly onto the soil, starting them indoors can give you a longer bloom period in areas with very short growing seasons. If you are starting several varieties, knowing how many of each you have helps you lay out a design with the various colors and sizes. While poppies are simple to grow from seed indoors, they do not transplant well. Start your poppy seeds six to eight weeks before the planting date in biodegradable containers that can be planted directly into the garden.
Mix 1 part humus-rich potting soil with 2 parts fine-textured vermiculite. Moisten the mixture before filling the containers. Place the containers into the slotted tray and fill them with the moistened mixture. Place the slotted tray into the solid soaking tray.
Mix the tiny poppy seeds with fine sand to avoid overseeding the pots. How much sand depends on how thinly you want them planted, but a ratio of 3 parts sand to 1 part seed is usually sufficient.
Sprinkle the seed and sand mixture onto a creased piece of paper and tap lightly to spread the seed onto the top of the soil. Cover them lightly with vermiculite and spray the top of the soil with water to help the seeds settle. Cover the seeds with plastic until they sprout, then remove the plastic.
Water the seeds from the bottom by filling the soaking tray with just enough water to keep the seeds evenly moist. Maintain good air circulation to prevent damping-off fungus from taking hold.
Thin the seedlings to one per pot when they reach 1 inch in height. To keep from disturbing the roots, use small scissors to clip off the unwanted seedlings instead of pulling them. Plant your poppies outside when there is no further danger of frost.