Best Fertilizer (Plant Food) for Hydrangeas

Hydrangeas are some of the rare gorgeous flowers that do not require much care and maintenance for growth. But that does not mean you can skip fertilizing them.

Instead, you need to use the best fertilizer for hydrangeas to ensure a beautiful bloom.

We have tested many products and come up with the 7 best candidates, which you can see in the following section. Our favorite is the Dr.Earth since it contains all-natural ingredients and is 100% safe for humans and pets.

Other products are worth your consideration too. Take a look!

A Guide To The Best Fertilizer For Hydrangeas

Miracle-Gro Pound – Best For Safety

Miracle-Gro 1000701 Pound (Fertilizer for Acid Loving Plant...
  • Instantly feeds acid-loving plants for lush foliage and...
  • Feed every 1-2 weeks
  • Helps acid-loving plants such as azalea, camellia, gardenia,...

It is a water-soluble product that comes in a 1.5-pound bag, covering about 600 square feet. 5-pound options are also available to treat up to 2,000 square feet.

This plant food supplies the plants with iron and other nutrients so that they can grow healthily. It feeds and acidifies plants simultaneously.

More notably, it is safe to use without burning other plants surrounding the hydrangeas.

You need to apply the Miracle-Gro plant food once on acid-loving plants, and it will last for 2 weeks. Once the plants absorb the nutrients, you can see beautiful blooms in your garden.

What We Like

  • Iron and other nutrients supplement
  • 100% safe to use
  • Two-week effect

What Can Be Improved?

  • Not for hydroponics uses

Osmocote Smart-Release Plant Food – Best For Versatility

Osmocote Smart-Release Plant Food Plus Outdoor & Indoor, 2...
19,499 Reviews
Osmocote Smart-Release Plant Food Plus Outdoor & Indoor, 2...
  • OSMOCOTE QUALITY: Osmocote is the original slow-release...
  • OSMOCOTE’S BEST FORMULA: Each homogeneous granule contains...
  • OSMOCOTE’S SECRET: Soil temperature controls how Osmocote...

It is fortified with 11 essential nutrients to ensure the hydrangeas thrive and bloom beautifully. Further, the NPK formulation is 15-9-12.

In fact, the plant food works with virtually all types of plants in all growing conditions. Feel free to apply the fertilizer to potted plants whether they grow indoors or outdoors.

The manufacturer offers a no-burn pledge as long as you use the product as directed.

We highly appreciate the twist-off cap that makes the application hassle-free. Sprinkle the granular nutrients, mix, water, and you are good to go.

What We Like

  • Hassle-free application
  • Applicable to all indoor and outdoor plants
  • Best for potted plants

What Can Be Improved?

  • Pricey for extensive uses

Jobe’s Organics Soil Acidifier – Best For Alkaline Soil

It contains the ideal formula for hydrangeas and blueberries, promising to turn hydrangeas from the ordinary pink color to blue.

The ingredients are all-natural, safe to use, and do not burn foliage. Once applied, the fertilizer will provide acid-loving plants with sulfur to correct alkaline soils.

This stuff smells good, but the beef-like smell may draw your cats and dogs to the plants. Thus, it is best to keep an eye on your pets after fertilizing hydrangeas with this Jobe’s product.

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The 6-pound bag is easy to pour. Make sure you test the soil pH before applying to achieve the best results.

On the negative side, we find the manual instructions poorly written. It is of little help in guiding beginners on how to use the fertilizer properly.

What We Like

  • Ideal formula for hydrangeas and blueberries
  • All-natural and safe ingredients
  • Sulfur supplement for alkaline soils

What Can Be Improved?

  • Poorly written instructions

Down To Earth All Natural Acid Mix Fertilizer – Best For Scent-free

Jobe's Organics, 09364, Soil Additive, Soil Acidifier, 6lbs,...
5,063 Reviews
Jobe's Organics, 09364, Soil Additive, Soil Acidifier, 6lbs,...
  • Organic granular for decreasing soils alkalinity; provides...
  • Omri listed for organic gardening by USDA; certified organic...
  • Ideal formula for hydrangeas and blueberries; turns...

It is specially blended for plants relying on acid, such as azaleas, camellias, blueberries, raspberries, strawberries, and of course, hydrangeas.

It contains the 4-3-6 formulation to encourage lush flowers and fruits. There are 2 options available, one-pound and five-pound bags.

You should apply this fertilizer twice, the first time in early spring for vegetative growth and again in fall when the plants start blooming. The second application will strengthen the root base and boost resistance to help the plants survive cold winter days.

Make sure you do a soil test first to know how much plant food you should feed plants.

What We Like

  • No strong smell
  • 4-3-6 formula for lush shrubs
  • Great value for the price

What Can Be Improved?

  • None so far

Espoma Holly Tone – Best For Evergreens

Down to Earth All Natural Acid Mix Fertilizer 4-3-6, 5 lb
2,721 Reviews
Down to Earth All Natural Acid Mix Fertilizer 4-3-6, 5 lb
  • A Natural fertilizer blended especially for acid lovers such...
  • To encourage lush flowers and fruit, apply Acid Mix in early...
  • Fall Applications can help promote root growth and boost...

It is formulated for many plants besides hydrangeas, including strawberries, blueberries, azaleas, evergreens, and so on.

For more effectiveness, the product also contains Bio-tone Beneficial Microbes. You will not find these microbes in any other brand.

Plus, this Espoma model is an organic fertilizer that does not contain any extra chemicals. Rest assured when using it when you have an all-organic garden.

The available sizes range from 36 pounds to 50 pounds. The more acid-loving plants you have, the bigger package you should buy.

What We Like

  • Specially formulated for acid-loving plants
  • Unique bio-tone beneficial microbes
  • Organic plant food

What Can Be Improved?

  • A little pricey

Dr.Earth Organic Acid Fertilizer – Best Overall

It is available in many sizes, and we highly suggest the four-pound polybag. It is enough to feed up to 80 small plants and 16 large-sized plants.

With a 3-4-3 NPK formula derived from Alfalfa meal, fish meal, fishbone meal, kelp meal, kelp flour, and potassium sulfate, the Dr.Earth fertilizer is a natural fertilizer for hydrangeas.

Due to the fast-release nature, its results are visible more quickly. Even 1 application is sufficient to show significant improvements. No worries about the hot summer days since this plant food can store water for dry conditions.

This product is safe for humans and pets, as long as you follow the manual guide.

What We Like

  • Natural fertilizer for acid-loving foliage
  • Friendly to humans and pets
  • Fast-release nature

What Can Be Improved?

  • Strong smell

Espoma Holly Tone Plant Food 4-3-4 – Best For Organic Gardens

Espoma Organic Holly-Tone 4-3-4 Natural & Organic Evergreen...
115 Reviews
Espoma Organic Holly-Tone 4-3-4 Natural & Organic Evergreen...
  • THE ORIGINAL: Holly-tone is the original plant food for all...
  • FOR USE ON: Not just for Holly; Use Holly-tone organic...
  • CONTAINS: Holly-tone is a rich blend of the finest natural &...

It is available in 3 sizes, including 18-pound, 36-pound, 50-pound bags. Depending on how many hydrangeas or acid-loving plants you have, you can choose the most suitable version.

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This hydrangea food contains the common 4-3-4 NPK formula, which consists of active ingredients, namely nitrogen, calcium, phosphate, sulfur, magnesium, and soluble potash. It is considered an organic fertilizer.

There are many natural materials, such as pasteurized, bone meal, alfalfa meal, greensand, etc. It contains little salt to ensure safety and avoid burning the soil.

The Espoma Holly Tone plant food is applicable to all acid-loving trees and plants. Within a few weeks of application, you will find your hydrangeas looking healthy and lush.

As an added perk, it is incredibly easy to use since you do not have to mix anything.

What We Like

  • All-natural food for hydrangea
  • Applicable to all acid-loving plants
  • Easy to use

What Can Be Improved?

  • Appealing odor to pets

The Comprehensive Buying Guide

Your Garden’s Soil Types

Hydrangeas prefer light soil that drains easily. Thus, if the soil you have is heavy, you should add some organic fertilizers to change its nature.

Before purchasing the best fertilizer for hydrangeas, it’s advisable to test the pH level to make the best out of the plant food.

For this, we highly recommend the home soil test kit. It is the cheapest and quickest way to test the soil pH.

Best Fertilizer (Plant Food) for Hydrangeas

First, dig a small hole in the soil and fill it with distilled water to test the pH. As the soil becomes muddy, insert the test probe and wait for the results.

If the pH reads lower than 7, your soil is acidic. In contrast, higher than 7 means alkaline soil.

Nutrients Content

Each nutrient plays a different role in plant growth. Knowing what nutrients your plants need will direct you to the right plant food.

For example, nitrogen is the one to help plants grow big quickly. Phosphorus is great for strengthening the root base, while potassium boosts resistance against potential drought and diseases.

On the other hand, magnesium allows the plants to process sunlight more effectively.

There are many more nutrients to come, so you may want to take your time learning about them. If you may not know, the amount of nutrients will determine how alkaline or acidic the plant food is.

For example, phosphate has the strongest acidifying effect, so fertilizers that contain much phosphate will increase the soil’s acidity by the highest margin.

NPK Ratio

It’s recommended to pay close attention to the NPK formula in your fertilizer since it will correct your soil’s nutrient deficiency to help plants thrive. Note that you need to choose the right NPK ratio to achieve the best possible results.

For example, if your hydrangeas are turning yellow, it means they lack nitrogen. In that case, you should use a fertilizer with a high amount of nitrogen.

Best Fertilizer (Plant Food) for Hydrangeas

The NPK formula is important too if you want to know how to make hydrangeas bloom. In this case, you should choose a fertilizer containing more phosphorus.

Meanwhile, potassium comes in handy when your plants are weak. Added potassium will strengthen the root systems and stems, allowing the plants to be more robust and vibrant.

Synthetic or Organic Fertilizers

Synthetic fertilizers have a fast-release nature and hence, showing results more quickly. They should be applied in the spring and require reapplication more frequently than slow-release plant foods.

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Meanwhile, organic fertilizers release nutrients slowly. They are more suitable for spring application and last longer in the soil.

Forms of Hydrangea Fertilizers


Granular refers to the dry fertilizer that you can apply with a spreader. It can be slow-release or quick-release.

Best Fertilizer (Plant Food) for Hydrangeas

A benefit that granular fertilizers offer is that you can see the actual fertilizers and apply them in the right area without all the guessworks.


Liquid fertilizers can be applied using a hose or a canister. It is incredibly easy to apply, and plants can absorb the nutrients more quickly and easily. However, liquid plant food needs to be diluted before the application.

Liquid fertilizer’s major downside is that it can be washed away by the rain. So it’s necessary to plan ahead and check the weather forecast to make sure there is no shower within 3 days of application.


Last but not least, we have spikes – stick-shaped fertilizers. They are slow-release fertilizers that should be applied directly to the ground.

Spikes are ideal fertilizers for beginners who grow acid-loving plants like hydrangeas for the first time.

Tips and Tricks on Fertilizing Hydrangeas

When To Fertilize Hydrangeas?

During spring or early summer, hydrangeas need slow-release fertilizers to grow healthily. Meanwhile, fast-release fertilizers will be more effective when applied in March, May, or July.

Best Fertilizer (Plant Food) for Hydrangeas

Fertilizing hydrangeas in the autumn is a good idea since the plants are preparing for dormancy at this time. The nutrients added will stimulate new growth and help the foliage survive the harsh winter.

How To Fertilize Hydrangeas?

Professionals highly recommend granular and slow-release plant food for hydrangeas. Potted plants may prefer liquid fertilizers to avoid burning issues.

When applying, make sure you scatter the fertilizer around the branches and water the plants well. Do not forget to cover it lightly with a thin layer of soil to activate the nutrients.

A small plant grown in the soil needs about ⅛ to ¼ cup of fertilizer with each application.

How To Care For Hydrangeas?

Hydrangeas need water to survive, so make sure you water them frequently, especially in the hot season. The plants will suffer if the soil becomes too dry.

In the autumn, you should cover the hydrangeas with leaves, pine needles, and straw. If possible, cover the entire plant with a cage filled with leaves. You also need the best fertilizer to care for the hydrangeas properly.

When do hydrangeas bloom?

The answer depends on the type of hydrangeas you grow and where you grow them.

Generally, hydrangeas come into buds in the early summer months and bloom in the following fall, spring, and summer seasons. However, the plants may stop blooming during summer due to the heat but begin to rebloom in the fall.

There is 1 reason why hydrangeas are unique: you can change their colors to your heart’s content.

To change the colors of the hydrangea, you should add a small amount of lime or sulfur. Lime will encourage the hydrangea blooms to turn pink while they will flourish in blue with sulfur.

But note that you cannot adjust the colors of all types of hydrangeas.

Great infomation for new gardeners:

The Bottom Line

The best fertilizer for hydrangeas aids in the plant growth and the blooming of the flowers. Take your time to read the buying guide and make a wise purchase decision from the seven options we have listed above.

Our ultimate choice is Dr.Earth. With its all-natural ingredients and ideal formula, we believe it will do wonderful to your beautiful hydrangeas.

Thank you for reading.

Last update on 2024-02-21 / Affiliate links / Images from Amazon Product Advertising API

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Jill Sandy

I am a sustainable focus gardener. I love decorating my home backyard with beautiful landscape design and creative garden care techniques I develop myself.