Why Are My Sunflowers Not Opening? + [How To MAke Them Open]

Why Are My Sunflowers Not Opening

Are you like me, a sunflower gardener, and can’t wait to see them open? I’ve been gardening for about 4 years now, and so far, nothing beats the feeling you get when your sunflowers finally open and how they shine in the morning sun. When the bees land on them, it’s magnificent. 

However, If you’re experiencing a challenge and wondering why your sunflowers are not opening, here are some reasons. 

It takes thirty days for sunflowers to open. You’ll know your sunflowers are ready to open when the stems become tall and sturdy, and the buds droop slightly. Your sunflowers may not open because it’s either too hot or too cold. Additionally, you may have added too much fertilizer as they grew. 

Read on to learn more.

Why Are My Sunflowers Not Opening?

It’s disappointing when you think you’ve done all you needed while planting only for your sunflowers not to open when you expected them to. If this is your situation, some reasons for your sunflowers not opening are listed below. 

  1. Poor growing conditions
  2. Pest infestation 
  3. Excess nitrogen 

You need to know more? Let me explain more below. 

  1. Poor Growing Conditions 

Your sunflowers aren’t opening because their growing conditions were poor. Some poor growing conditions include excess or little light. 

Sunflowers need up to 6 hours of the morning sun to open once they’re grown. Therefore, too little light stunts their growth while too much light scorches them. 

Moreover, the heat from the sun is necessary to note while looking into why your sunflowers aren’t opening. Heat exceeding 30˚C is harmful to the flower. Excess light and high temperatures lead to scorching. You’ll notice they’ll start closing up, drooping, and finally falling and dying. 

Additionally, if they’re receiving poor nutrition from the soil they’re planted on, they won’t open. Soils such as sand aren’t good for sunflowers. 

  1. Pest Infestation 

Similar to other plants, sunflowers are susceptible to pest and insect attacks. Suppose they’ve been attacked by any pests before their full growth, the chances of sunflowers opening lowers. 

A common problem to watch out for is the sunflower midge pest that remains inactive in the soil, only to attack when your flowers open. They look like swelled-up larvae. You’ll notice them in the bud of sunflowers when they’re about to open. 

In the event of your sunflowers having these pests, spray pesticides immediately.

  1. Excess Nitrogen 

Although it’s true that your sunflowers won’t open if they get little nutrients from the soil, it’s also true that too much nutrients will do the same. 

Markedly, if sunflowers receive excess nitrogen, it stunts their growth. If your soils have excess nitrogen, replant your sunflowers. 

How Do You Get Sunflowers to Open Up?

You can get sunflowers to open up by controlling the sunlight and temperature exposure. Even though sunflowers need 6 hours of daylight,  high temperatures may lead to them wilting. 

To remediate the situation, therefore, cover your sunflowers with green nets as they start blooming. 

Additionally, providing sunflowers with filtered water every day as they bloom improves their capability of opening. 

Why Has My Sunflower Closed?

Your sunflower has closed because of overwatering. People make a common mistake; once they notice their sunflowers have opened, they overwater because of fear of closing. Be careful, though, underwatering also causes the same issue – sunflowers close. 

Even though open sunflowers indicate maturity, they still need care; keep watering (water enough, not excess or too little) them every day until you harvest the seeds. 

Sunflowers bloom with long stems and beautiful wide flowers; sometimes, these flowers may bloom away from the sun. You’ll need to prune plants you’re willing to lose to expose the sunflowers to the morning light. 

Replanting sunflowers at the opening stage kills them; therefore, look into clearing their line of sight to the sun instead.

How Long Do Sunflowers Take to Open Up?

It takes up to thirty days for sunflowers to open. Once they’ve fully matured, the blooming phase lasts close to ninety days. 

Additionally, you’ll know your flowers are ready to open when bees start to migrate to your garden and nudge the buds. 

How Do You Perk Up Sunflowers?

You can perk up sunflowers by following these steps;

  1. Water Your Sunflowers

Perking is similar to the opening in gardening. The difference is in where the sunflower is as it opens. Sunflowers open in the garden and perk up after you pick them. 

To ensure your sunflower remains open even in a vase, water it thoroughly while still in the garden. Thorough water doesn’t mean excess watering. 

On the contrary, it means carefully watering your flowers exactly when they need it without fail, at least, until the soil is moist. This, however, applies when they’re in a growing phase. 

  1. Cut Your Flowers Early

To make sure that your sunflowers remain perky and open longer, pick them up early in the morning. 

  1. Angle Your Cutting

Sunflowers have delicate leaves and stems; if not cut right, they wilt. Therefore, while plucking, hold your scissor at an angle to increase the support surface area for the branch. 

Moreover, cutting at an angle gives the open flower space to take water when placed in a vase. 

Straight-cut stems block their ends in a vase, making it more likely for the flower to close up from dehydration. 

  1. Put Flowers in Water Immediately

Your flowers wilt immediately after opening if you don’t care for them well. Therefore, once your sunflowers have opened and you’ve picked them, to keep them perky, put them in water. 

It’s better to have your vase and water ready before cutting the flowers, so they don’t lie waiting for you and wither. 

  1. Use Filtered Water

Filtered water has fewer bacteria than regular tap water. While using filtered water, remember to change the water in the vase every day. 

The idea for keeping your sunflowers open is to ensure the bacteria around them is minimal. Additionally, changing the water daily and using filtered water reduces the pungent smell of sunflowers. 


Do Sunflowers like Sugar Water?

No, sunflowers don’t like sugar water. As they grow, watering them with a bit of sugar water promotes reverse osmosis, causing dehydration. 

If your seedlings are dehydrated, it stunts sunflower opening even when mature. 

How Often Should I Water My Sunflowers for them to Open?

You should water your sunflowers daily for them to open. However, take caution about the purity of water and the quantity of water you’re giving the flowers. Sunflowers are prone to getting harmful bacteria from water. 

Use filtered water when spraying the garden. Additionally, water the flowers up to 2.5cm of water weekly to open best. 

Do Sunflowers Need Total Sun Exposure to Open?

No, sunflowers don’t need total sun exposure to open. Sunflowers only need up to 6 hours of morning sun to open once they’ve matured. The morning sun isn’t too hot on their delicate leaves, hence perfect. 

Therefore, plant them in spaces that receive sun and allow for shade during high noon to avoid scorching your flowers. 

Will My Sunflowers Open Throughout the Year?

No, unfortunately, your sunflower won’t open throughout the year. Although various sunflowers are annual bloomers, it’s unlikely they’ll remain open throughout the seasons. 

Usually, sunflowers close up and wilt during the wintertime because of little light and heat to keep them flowering. 

However, seeds may self-germinate and open even during winter if they fall on the soil during the blooming phase. 

What Months do Sunflowers Open?

Sunflowers bloom in different months, depending on the variety you’ve planted. Annual sunflowers bloom during the spring and autumn, while perennial flowers bloom in early July and late October. 

Do Sunflowers Open in Pots?

Yes, sunflowers open in pots. However, it’s only a guarantee if you place the pot where adequate light and heat reach the sunflower. Additionally, while the flower is potted, ensure you water it as needed. 

Since it’s in a pot, you won’t need as much water as you would if it was in the garden-just ensure the soil is moist after watering but not flooding.

Something to note is that while sunflowers open in pots, they don’t grow and spread as tall and as vibrant as the ones growing outside in a garden do. This is because of the limited movement space for the roots and stems. 

How Do I Know When My Sunflower is about to Open?

You’ll know your sunflower is about to open when you notice the buds drooping a little. It means it has become heavy with seeds. 

You’ll also see bees and other birds coming to patch and nudge the buds often; this means they can smell the nectar. 

Additionally, the stem grows long and sturdy when sunflowers are ready to open; since the top flower part gets heavy, the stem grows to support. 


I bet you’ve learned more than enough facts about sunflowers, and you’re now ready to address them and make sure they open. While taking the mentioned precautions above, be gentle. Sunflowers are tall, beautiful flowers, but they’re also very delicate. 

Since the top flower part is quite heavy, always exercise caution when checking the buds. 

It’s frustrating to wait for sunflowers to open; they’re truly a magnificent sight but be patient. Instead, take a close look at each change, notice if there are any pests hidden in the buds, and keep watering only the required amount of water. Your sunflowers are sure to open.