Petunia Not Blooming: How To Fix Petunia Plant With No Flowers

Purple Petunias
(Image credit: Maryna Skazochkina)

A summer blooming favorite, many gardeners use petunias to add color to beds, borders, and containers. Blooms are usually reliable until autumn, but what do you do if you have non-blooming petunias? Learning how to make petunias bloom is fairly simple. Read more to find out what may have caused the petunia plant with no flowers.

Reasons for Petunia Not Blooming

Here are the most common reasons for a petunia plant not blooming:

Poor lighting

When you find there are no blooms on petunias, the first thing is to check is the amount of light the non-blooming petunias are receiving. Check at various times of day to see if the petunia plants with no flowers are getting direct sunshine. Petunias need full sun for the most optimum show of blossoms. The plant may bloom when it is lightly shaded for part of the day, but as a rule, a petunia not blooming can be because it does not get at least six hours of direct sun per day. Move container planted petunias plants with no flowers into a sunny location. Ground planted, non-blooming petunias can get more sun by thinning or trimming surrounding plants that may be shading them. If you've planted petunias in a shady spot that can't be remedied, you may need to replant the petunia plant with no flowers.

Wrong fertilizer

If the lighting is correct and there are no blooms on petunias, perhaps they're not getting enough water or fertilization. Petunias are somewhat drought tolerant but will provide a more lush display when the soil is kept moist. Shake off excess water that is on the developing blooms of ground planted petunias; wet buds can rot away before blooming. If you haven't been feeding the petunia plant with no flowers, perhaps you should try this remedy. Many plants grown in nurseries are regularly fed with liquid fertilizer, but it only remains in the soil until it washes out from watering. It is possible that the petunias have been fertilized with a high nitrogen plant food, resulting in lush foliage, but non-blooming petunias. Change to a phosphorus heavy fertilizer, such as those labeled ‘bloom buster.' Bone meal is also a good source of phosphorus. Phosphorus is the middle number in the 3-digit fertilizer ratio listed on the packaging. Choose a product labeled 10/30/10. A balanced fertilizer may be effective toward summer's end if you're hoping for a final performance from your petunias.

How to Make Petunias Bloom Later

Deadheading spent blooms will encourage the production of more flowers. If foliage begins to brown and die as summer wanes, clip it off right above a set of healthy leaves. Pinch back the center of the stalks. Fertilize at this time with a balanced fertilizer, but one that has a high phosphorous number, such as 30/30/30. Enjoy the long lasting blooms of those petunias.

Becca Badgett

Becca Badgett was a regular contributor to Gardening Know How for ten years. Co-author of the book How to Grow an EMERGENCY Garden, Becca specializes in succulent and cactus gardening.