Live to Plant

Cosmos Plant Harvesting:
Optimal Time and Technique

Updated: December 27, 2022

Cosmos is a beautiful flowering plant that is commonly grown in gardens and landscapes. It comes in various colors such as pink, purple, red, and white. Cosmos is an annual plant, which means it grows, flowers, and dies within a year. To get the most out of your cosmos plant, it’s essential to harvest it at the optimal time and using the right technique. In this article, we will discuss the best ways to harvest cosmos plants.

When to Harvest Cosmos Plants

The best time to harvest cosmos plants is when the flowers are fully open but have not yet begun to fade. The petals of the flower should be firm to the touch and have a bright color. If you wait too long to harvest the cosmos plants, you may end up with faded flowers that are no longer attractive.

It’s also important to note that the time of day you choose to harvest your cosmos plant can affect its quality. The best time to harvest cosmos plants is early in the morning or late in the evening when temperatures are cooler. This is because when it’s too hot outside, flowers tend to wilt quickly after being cut.

Techniques for Harvesting Cosmos Plants

There are two main techniques for harvesting cosmos plants: deadheading and cutting.


Deadheading involves removing spent flowers from the plant. This technique encourages more blooms to grow throughout the season, which means you’ll have more flowers to enjoy. Deadheading also helps keep your cosmos plant looking neat and tidy.

To deadhead your cosmos plant, simply pinch off the spent flower using your fingers or a pair of pruning shears. Make sure to remove the entire flower head including any seed pods that may have formed.


Cutting involves removing entire stems from the plant. This technique is best for harvesting flowers for use in floral arrangements or for drying.

To cut your cosmos plant, use a pair of sharp pruning shears to snip the stem just above the first set of leaves. This will encourage your plant to produce more stems and flowers.

Tips for Harvesting Cosmos Plants

Here are some tips to keep in mind when harvesting cosmos plants:

  • Always use sharp pruning shears or scissors to prevent damaging the plant.
  • Harvest your cosmos plants regularly to encourage new growth and more blooms.
  • Cut flowers early in the morning or late in the evening when temperatures are cooler.
  • When cutting flowers for arrangements, strip off any leaves that will be submerged in water to prevent them from rotting.


Can I harvest cosmos plants after they’ve started to fade?

It’s best to harvest cosmos plants when the flowers are at their peak, so you’ll get the most vibrant blooms. However, you can still harvest faded flowers for use in dried arrangements.

How often should I deadhead my cosmos plants?

You should deadhead your cosmos plants regularly throughout the growing season. This will encourage new growth and more blooms.

Can I cut my cosmos plants back to encourage more growth?

Yes, you can cut back your cosmos plants by a third to half their height after they’ve finished blooming. This will encourage new growth and more flowers.