is reader-supported. That means as an Amazon Associate we may earn a small commission from qualifying purchases (at absolutely no extra cost to you).

Cosmos are little colorful flowers, similar looking to daisies. During the summer months, they’ll attract bees, birds, and butterflies to your garden.

Cosmos are a gardener’s favorite, not only because they are very easy to grow and care for, but for the cloud of attractive color they form in the garden. They also make excellent cut flowers to take indoors. 

Read on below and learn everything you need to know about planting and caring for Cosmos flowers if you’re considering adding them to your garden. 

About Growing Cosmos

close up shot of cosmos in bloom
Photo by Rafid Tahmid on

Cosmos are one of the best flower species to plant in the spring months of April and May. From the time of planting cosmos seeds, they take just under two months until blooming.

These gorgeous flowers prefer a location in flowerbeds, pots, balconies, or your garden, where the sun shines for at least 8 hours per day.

So long as you choose the right time of year (the spring), cosmos are among the very easiest flowers to grow. The best range of temperatures for cosmos is 70F to 75F.

Cosmos are beautiful flowering plants that belong to the sunflowers family. They are native to Mexico, where most of the species grow.

The symbolic meaning of these flowers is order and harmony, and it comes from the flower’s name.

Cosmos also symbolize love, peace, modesty, innocence, and joy. This beautiful flower species come in a wide variety of colors, including pink, red, yellow, orange, and white. 

Quick Cosmos Growing Information

How much light is needed:At least 8 hours. Cosmos grow better with full sun exposure, except in extreme heat, in which case they can tolerate some shade. 
How much water is needed:You have to water regularly but Cosmos are drought-tolerant, so make sure not to over-water. That will result in fewer flowers.
Is it best to start with seeds or plants:Cosmos is very easy to start from seeds and they germinate relatively fast.
The best month to plant:Early spring is the best time to sow Cosmos seeds. If you start your seeds in small pots indoors, late April or May will be the perfect months to transplant them to your garden.
Preferred climate/temperature:
Temperatures between 70F and 75F are optimum for Cosmos’ growth. 
Is indoor or outdoor growing better:Cosmos plants benefit from being started indoors, but they can be started outdoors after the last frost has passed.
Do indoor plants need to be pollinated:Cosmos rely on insects for pollination when outdoors. For that reason, indoor Cosmos need to be pollinated. 
Level of difficulty to grow:Very easy. 
Plant height:Between 18 to 60 inches tall. 
Time from planting to harvest:Approximately 7 weeks. 

Planting Cosmos

field of pink and white flowers
Photo by 세훈 오 on

Cosmos are very easy to grow and do not need much time before you start enjoying the results.

Find below simple step-by-step guidelines on how to plant Cosmos:

1. The first step will be to choose the right spot and prepare the soil. Remember Cosmos need long hours of sun exposure. The soil, on the other hand, does not need to be too rich, but it does have to be well-drained.

2. Sow Cosmos’ seeds lightly and not too deep. Only a ¼ of an inch would be enough. 

3. Remember Cosmos grow between 18 and 60 inches high. Plant them at least 12 inches apart. 

4. Water regularly, but not too much. Cosmos tolerate warm, dry weather and drought. Overwatering your Cosmos will result in fewer flowers.  

Harvesting Cosmos

close up shot of cosmos flowers
Photo by Debraj Chanda on

Cosmos are beautiful cut flowers and can last a week or more in a vase with water.

Here is a step-by-step guide on how to cut the Cosmos flowers from your garden to take them inside your home:

1. From the moment they start blooming, it’ll be the right time to start cutting your Cosmos flowers. 

2. Pick the ones with the petals fully opened and use pruning shears to cut the stems. 

3. Remove the lower leaves, so they will not touch the water. Put the flowers in a vase. 

4. If you want to harvest more seeds, remember to leave some flowers in your garden as they self-seed.

Cosmos Growing FAQs

Do Cosmos Come Back Every Year?

Most varieties of Cosmos plants are annual, meaning you’ll have to resow them every year. There are only a few varieties of Cosmos that are perennial, including Chocolate Cosmos and Cosmos atrosanguineus. 

Do Cosmos Need Staking?

Because Cosmos can grow very high, staking may be necessary. You can also grow them against a fence so you provide the long stems with the necessary support and protection from the wind. 

Do Cosmos Need Fertilizing?

Cosmos plants are very easy to take care of. Once they’re established they need little water, no fertilizer, and not much care. In rich soils, Cosmos produce weak stems, late-blooming, and not many flowers. 

Suggested Reading: How to Grow Carnations

Amazon and the Amazon logo are trademarks of, Inc, or its affiliates.