How And When To Fertilize Petunias

Adding petunia fertilizer to your gorgeous flowering beds or pots is crucial for heavy-feeding petunias.

A gloved hand fertilizing a petunia
(Image credit: evgenyb / Getty Images)

Do You Need To Fertilize Petunias?

Most garden experts agree that petunias are considered “heavy feeders.” Since these plants grow quite quickly, the availability of nutrients in the soil is paramount. This is especially true of varieties that are known for their productivity and stunning floral displays.

Learning more about when and how to properly fertilize petunia plants is essential to their growth, as well as their continued bloom throughout the summer. This applies to those planted in ornamental beds, as well as petunias in pots, containers, and hanging baskets.

How Often to Fertilize Petunias

Petunias grown in ornamental garden beds benefit from routine feeding, but they generally need much less than those in pots. Fertilizer for petunias in pots is especially important throughout their growing season, as nutrient levels quickly become depleted.

When to Fertilize Petunias

Petunia fertilizer is best used during periods of active growth. This includes amending the soil in preparation for planting, as well as regular feeding throughout the summer season. Though most manufacturer’s labels give growers specific directions as to the frequency of application, many non-commercial and organic products should be used based only on your soil’s composition and any soil deficiencies within your garden beds. Experienced growers often rely on soil tests to better meet the needs of their bedding plants.

How to Fertilize Petunias

Fertilizing plants properly depends greatly on the type of food being used. This is especially important with commercial fertilizers, which should be used only as directed. Granular fertilizers are most common and are worked directly into the soil at planting time. Granules or pellets can be used to side-dress plants, as well. This usually occurs later in the season, just before the production of flowers.

Water-soluble fertilizers refer to those that are diluted and used as foliar feed or soil drench. These types of feeds are generally used with greater frequency and are known for their ability to quickly deliver nutrients to plants.

Best Fertilizer for Petunias

Determining the best fertilizer for petunias varies and depends on several factors. At planting time, petunias can be placed into beds with soil that has been amended well. Experienced gardeners most often use a finished compost and a slow-release granular feed.

Petunia containers and pots should be filled with a high-quality potting mix. Foliar and water-soluble feeds can then be used throughout the summer to help maintain adequate nutrient levels for the continued production of flowers. Other types of fertilizer used with petunia plants include compost teas, blood meal, bone meal, and fish emulsion.

Frequently Asked Questions

What Fertilizer Makes Petunias Bloom?

The best way to promote bloom in petunia plants is through the use of a well-balanced feed. Granulated fertilizers can be worked into garden soil at planting time, providing a much-needed “jump start” to new annuals. Throughout the season, water-soluble feeds are used to continue flower production and maintain lush foliage.

What Does Epsom Salt Do For Petunias?

Using Epsom salt on petunias is popular. Some think adding it to garden soils and potted plants helps promote growth and improve the overall production of flowers. While experts often remain skeptical of these claims, some gardeners swear by its use and dependability as a feed.

Tonya Barnett

Tonya Barnett has been gardening for 13 years. Flowers are her passion. She has trasformed her backyard into a cut flower garden, which she regularly chronicles on her YouTube channel