5 Reasons For Petunias Not Blooming [How To Make Bloom]

It’s summertime and your petunias are not blooming? 

It’s very normal to be frustrated If your petunias have bloomed once but not blooming this time. You must be wondering what causes the petunias to stop blooming. Well, petunias require a bit of care to produce their beautiful blooms.

But why do petunias stop blooming?

There are 5 major reasons for petunias not blooming including poor sunlight, underwatering, lack of space, low nutrients & budworms.

In this article, I am going to explain why the petunias won’t bloom and also discuss how to make them bloom.

So without making any delay let’s jump right in-

Reasons & Solutions For Petunia Not Blooming

1. Poor Sunlight

When your petunias are not blooming the first thing you need to check is the availability of sunlight. Petunias need at least 6 hours of direct sun every day for blooming. If the petunias are shaded they produce poor quality bloom or stop blooming at all.

Control Measure

When your Petunias look healthy but not blooming then you need to relocate them to get enough sun. If they are planted in the ground, replant them in a sunny location. Move the potted petunias to a sunny location. Make sure they are getting at least 6-7 hours of sunlight.

2. Petunias On Low Fertilizer

If the petunias are getting enough sunlight but still not flowering they might be low on nutrients. For good quality blooming wave petunias need a good dose of fertilizer. Well-fed petunias will produce lots of blooms. 

Control Measure

To revive the petunia blooms fertilize once a month. Feed your petunias with the best blooming fertilizer during summer (our pick: Miracle-Gro Water Soluble Bloom Booster Flower Food). Apply the fertilizer according to the label directions.

Do not apply high nitrogenous fertilizer. It will promote leaf growth but it will not help to bloom. You can also apply bone meal and blood meal. Fertilize the potted petunias very lightly every 10 days.

Here is the homemade fertilizer for petunias-

#Recipe 1:-Homemade Bloom Fertilizer Recipe


  •  200 grams of any fruit (pumpkin, zucchini, banana, mango, etc.) But avoid citrus fruits. The best combination is Banana: Zucchini: Pumpkin
  • 200 grams of Brown Sugar 


  • Mash the fruits
  • Add the sugar and mix well
  • Keep this mixture in a bowl and cover loosely
  • Let it stay for 7-15 days for fermentation
  • After fermentation, you will get juice.
  • Drain the juice and store it in a bottle.
  • Add 1 tablespoon of this mixture in 5 liters of water and put it into the sprayer and spray on your petunias.
  • You can apply this directly to the soil

3. Wrong Watering On Petunias

During blooming, petunias need more water than usual. Petunias are pretty drought-tolerant but they love moist soil for good blooming.

Giving them the right amount of water is very crucial. Because underwatered petunias will fail to bloom. Overwatering will suffocate the petunia roots and cause fungal diseases like root rot. 

Control Measure

Get a moisture meter to water the petunias correctly (Our pick: Atree Soil Soil Tester Kits with Moisture, Light, and PH Test for Garden)

Plant the petunias in well-draining soil. In the case of potted petunias use a high-quality potting mixture (Our Pick: Espoma Organic Potting Mix)

Add organic composts to improve soil drainage. When you are watering more to get better blooming, keep an eye on the leaves. If they are becoming yellow, you are overwatering them. Cut back on the watering then immediately. 

Don’t wet the foliage. Because it can lead to fungal diseases that stop blooming. Water them at the ground level.

4. Petunias Lacking Space

If you want your petunias to bloom you need to give them space to grow. Because Petunias are spreaders. Wave petunias can spread their vines up to 5 feet long. 

When petunias are grown in pots or in hanging baskets, the roots have little space. So, the roots don’t help to grow enough flowers. As a result, the potted petunias fail to bloom.

Control Measure

Make sure you are providing your petunias enough space. Plant them at least 1 foot apart.

Replant the petunias in a bigger pot if they have grown out of the previous one. Prune your Mexican petunias in late winter or early spring and remove the stems damaged by frost.

5. Budworms

Budworms are one kind of caterpillar that hide inside the buds. They eat the flower buds from the inside. So, most of the time they are not even seen. Budworms are very harmful to petunias. As a result of their feeding, the flower bud won’t open.

Control Measure

Always inspect your petunias carefully because the budworms stay hidden inside the flower buds. Apply the best and most effective insecticide for these budworms (our pick: Monterey Bacillus Thuringiensis (B.t.) Worm & Caterpillar Killer Insecticide)

Try these homemade recipes of insecticides for your petunias-

#Recipe 1:- Chilli Spray Recipe


  • 1 teaspoon ground chili
  • 2 liters of water


  • Mix them together and simply spray on your petunias

#Recipe2:-Insecticidal Soap Recipe

Cooking oil mixed with mild liquid soap can be very effective against budworms.


  • 250 ml of any cooking oil
  • 1 tablespoon of liquid dish soap


  • Add the two ingredients together and mix thoroughly
  • Store this in a bottle.
  • Add 2 teaspoons of this mixture to one liter of water
  • spray directly into the buds.

#Recipe 3:- All-In-One Insect Spray Recipe


  •  1 small bulb of garlic
  • 1 small onion
  • 1 teaspoon dry pepper powder
  • 1 tablespoon of liquid dish soap


  • Make a paste of the garlic and onion in an electric blender.
  • Add the dry pepper powder to the paste. Mix it. Then let it sit for a few hours.
  • Strain the mixture and add the liquid dish soap and mix very well
  • Make it a 2-liter solution by adding water.
  • Be careful while handling the mixture as it contains hot pepper. 
  • Spray this solution on your petunias

Note: Always use a small amount of these recipes on your petunias. Start with a small leaf and if the leaf burns then add more water to the solution. Then try with another small leaf again.

How to Keep Petunias Blooming All Summer

Petunias need constant grooming. To keep the petunias blooming you need to provide them plenty of sunlight and water with the best fertilizers. If the flower bloomed once but is no longer blooming then cut them back by half its length.

One of the best ways to keep wave petunias blooming is by deadheading the older blooms. Cutting back the spent blooms can encourage new blooms. 

Frequently Asked Questions (FAQs)

When Do Petunias Bloom?

Petunias bloom all summer and spring until the frost arrives. 

Do Petunias Bloom All Summer?    

Petunias are very popular summer flowers. They bloom all summer up until autumn with the help of a little deadheading.


If your petunias are not blooming, it means they need more care. Make sure you are providing them with enough sunlight and water. Treat them with the best phosphorus and potassium-rich blooming Petunias fertilizer. Protect them from budworms with insecticide.

By reading through this article now you know how to make your petunias bloom. You need to deadhead the spent blooms. So, go out there and work on your pretty petunias. Your garden is sure to get the fragrance of petunia blooms.

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