Why Is My Cosmos Not Flowering

Worried about why is my Cosmos not flowering? Maybe the reasons is overwatering or overuse of fertilizers. But there are some easy peasy solutions to make your cosmos plant bloom again.

So, stop worrying because you will get all your answers in this article. We are gonna share some tips to treat and care for your Cosmos while they are small so that they become bushier and fill your yard with lots and lots of flowers.

Why Is My Cosmos Not Flowering?

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Cosmos is dark pink in color, but when the bud starts opening up and the flower passes a few days, it becomes a bit lighter and looks heavenly! Once you sow the seedlings, they might not look so smashing, but they definitely will with your proper care!

However, check out the table below where we mentioned the possible reasons for the cosmos not flowering and the solutions.

Probable ReasonsSolutions
When the plan develops only one flower on the topPinching
Excess wateringThe solid should be just moist
Attack of pestsApply pesticides in a moderate amount
Overuse of fertilizerApply fertilizer in a moderate amount
Soil qualityCosmos tend to flower poorly in high-quality soil.

With the reasons and one-step solutions, you might wonder why are some of my Cosmos not flowering.

Hence time to discuss elaborately with all the explanations that you must know:


This pinching is not the same that you do with vegetables. Since Cosmos is a summer flower, it needs pinching and, of course, in a different way.

When the plant is tall, it will produce energy to grow taller. Then it will develop a flower on the top. Now once you remove the top, the cosmos plant will figure out how to produce new side shoots with new flowers to produce new seeds.

However, the side shoots will grow faster, and they will grow even more if you cut down the top of the plant. So you must pinch or remove the top of the Cosmos regularly for all the side shoots to develop and grow flowers rapidly. Being a big plant already, you can imagine the marvelous look of it filled with flowers!

Put The Top Cut Part In Soil Again

Now the top part that you gonna remove don’t throw it out. Instead, you can put it in the soil as cosmos roots easily from cuttings. As a result, it will start rooting in a week.

Spacious Space For The Cosmos

Choose a suitable size spot where there is enough space for them to grow properly.  Also, make sure to have a better drainage system. You can grow Cosmos in any kind of soil if your drainage system is good.

Low-Quality Medium Moisture Soil

Medium moisture and well-drained soil encourage Cosmos to flower more. In most cases, the cosmos grow very well in poor soil quality.

Enough Sunlight

Ensure that your Cosmos gets enough sunlight for best results- at least six to eight hours of direct sunlight. However, during extreme summer, you need to lessen the hours or avoid direct sunlight. Otherwise, the leaves might burn.

Proper Usage Of Fertilizer

Add 2-3 tbsp of bone meal every 12 to 15 days and add some mustard cake liquid fertilizer weekly. Do not give them too much fertilizer as it will weaken their capacity to flower rapidly.

However, if you plant them in containers, use a decent amount of compost—for instance, 60 and 40% of garden soil and compost, respectively.


Water your Cosmos properly. Besides, the general rule of thumb is to water them once a day. During the summer, you may water them twice. However, don’t use excessive water on the soil. Pour water only when you feel the soil is dry. The Cosmos plants might survive direct sunlight, but they cannot tolerate excessive water. Just pour water for the soil to moisten.

Attack Of Pests

Cosmos also get attacked by pests frequently. So you should make some neem oil spray or other organic pesticides once a week. This will keep them healthy and safe.

Another important thing is to prune the dead flowers. Take out the seedlings and preserve them for your next planting.

Presence Of Spider Mites

Again, one of the most underrated reasons why the Cosmos plants do not flower is because of the presence of spider mites. So whenever you find its presence around your Cosmos, splash water spray to destroy it.

When Does Cosmos Bloom?

The best time for Cosmos to bloom and flower is during March or April. This is the time when the heat of the sun is bearable for the plants to adapt and grow properly. 

Other than this time of the year, it gets difficult to grow Cosmos. And the process becomes very slow. But with patience and the right efforts and care, you will definitely see the results!

A Helpful Tutorial You May Need!

Frequently Asked Questions (FAQs)

This section includes some frequently asked questions concerning the flowering of the Cosmos. In case if you have these same questions revolving around your mind, consider taking a look.

How do I get my cosmos to flower?

The best and fastest way to get your cosmos to flower is via pinching. Usually, the Cosmos stem is tall enough, but it tends to develop a flower at the top. So to get more flowers, you could pinch the Cosmos.

What month does cosmos flower?

Cosmos flower the most during March/April. This is the time when direct sunlight turns out to be beneficial for flowering.

What to do if plants are not flowering?

If your plant looks healthy growing yet not flowering, inspect the reason. If this is due to soil, use low-quality soil. Check the ingredients of the fertilizer. If it contains too much Nitrogen, change your fertilizer. Look for spider mites. Stop pouring excessive water. Make sure they get enough sunlight.


Hopefully, you find all the answers concerning why is my Cosmos not flowering. Taking care of Cosmos is not a hassle. However, it grows perfectly in the low-quality soil as well, so you never got to worry!

And tell us who doesn’t love the beauty of these pinky Cosmos glorifying your yard? You are having a dull day, just looking at them will relieve your stress! Truly beautiful and super-easy to take care of.

By admin