Poppies look great in containers with foliage plants, other wildflowers or with a lower-growing flowering plant to give the container garden some height. The shortest of the poppies are called Iceland poppies, which grow to about a foot high. Other poppies can grow as much as 3 feet tall and look wonderful in large container gardens. You can purchase poppy plants at garden centers in season, or you can grow your own from seed and place them into containers when they're ready.
Plan out your container garden. If you're going to plant other plants with the poppies, figure out how the plants can be used together, such as placing the poppies in the center or along the back of the container for height and then working smaller plants to trailing plants around them. If you're planting only poppies, choose colors that will complement each other and different types for various heights.
Purchase poppy plants in biodegradable pots such as peat pots because poppies do not like to be transplanted. This will allow you to plant them without ever disturbing their root system.
Fill your container with potting soil to within an inch of the top for watering purposes. Mound some of the soil in the center to give extra height to the middle of the garden.
Plant the poppies in the container so the top of the peat pots are at the same soil level as the surrounding soil. Poppies do not mind being slightly crowded, so, plant as many as you want according to your plan. Fill in with other plants if you choose to.
Water in the plants well to help establish the roots and settle the soil around them. Fill in with more soil if it settles too much and the peat pots are sticking out. Water the plants every other day for two weeks while the roots are getting established in the container. Then cut back to whenever the top of the soil starts to feel dry.
Fertilize with a liquid flower fertilizer once a month. Follow the manufacturer's directions on the amount to use according to how large the container is and what types of plants you have in it.
Place your container in full sun or morning sun with some afternoon shade. Put snail-bait traps around the container because snails and slugs will eat the plants before they ever produce a flower. Read caution labels on the snail bait because most are poisonous to children and pets.
Pinch off dead flower heads to encourage new flowers. Allow the foliage of annual poppies to die and then pull them out of the container and discard them. Perennial poppies can have the dead foliage cut off and the container can be mulched over for winter or placed in a garage and brought out the following spring.