4 Steps to Growing Cosmos in Containers

Derived from the Greek word for “beautiful,” Cosmos are one of the prettiest and easiest annual flowers to grow in containers whether you grow them from seeds or seedlings. This article will give you a step by step analysis of how to grow Cosmos in a container from seeds.

Step 1: Purchase and Prepare the Container

Purchase a container from a reputable store; make sure that the container is equipped with drainage holes on the bottom. The container’s soil capacity should be at least one gallon of soil; this way your cosmos will have room to populate the entire pot.

Fill the bottom inch of the container with gravel; gravel is essential to maintaining healthy drainage and it helps prevent the soil in your container from becoming compacted.

Fill the rest of the pot with fresh potting soil; it is best to choose an organic soil that contains a time release fertilizer. Since cosmos can adapt to almost any soil condition, do not worry if you cannot locate an organic soil mix.

Step 2: Purchase Reliable Seeds and Sow

It is a good idea to purchase your Cosmo seeds from a local nursery; this way you will know you’re getting a local and reliable product. Also, many nurseries keep community experts on staff. Buying from a nursery will give you the chance to consult these experts on how to successfully grow Cosmos in your specific environment.

Once you have purchased your seeds, look on the back of the packet for sowing instructions. Most seed packets assert that Cosmos should be planted when there is no risk of a frost, about half an inch deep into the soil.

When planting time arrives, make sure that the soil in your container is thoroughly moistened, otherwise the seeds will not germinate. The easiest way to sow Cosmos is to sprinkle the entire seed packet around your container using your fingers. Cover the seeds with a thin layer of soil before considering the process complete. The seeds should sprout between five and ten days after planting.

Step 3: Thin the Crop When Appropriate

You will likely need to thin your Cosmos a couple weeks after they begin sprouting. Even though the sight of a container jam-packed with seedlings is exciting, it is necessary to thin them in order for the plants to thrive. Thin the seedling according to what the back of the seed packet prescribes. This process opens up space in the soil for the plants to spread their roots and become healthy adults.

Step 4: Basic Care and Maintenance

Expect your Cosmos to bloom all summer and part of fall, until the first frost arrives. While the plants are growing and blooming, it is important that you know how to care for them.

Create a care schedule for your Cosmos where you water them once a week, and fertilize them once every other watering. If your cosmos become too large to support themselves, use wooden stakes or a trellis to keep the plants from falling over.