Can You Use Ericaceous Compost on Hydrangeas?

Acid-loving plants like hydrangeas benefit from ericaceous compost that raises the acidity of the soil and helps to alter the bloom color of hydrangeas.

If the soil in your garden or planters is otherwise alkaline, this special compost is a quick way to change that. I’ll cover the best ericaceous composts for hydrangeas and I’m going to present to you an easy way to make the soil more acidic and more adapted to the needs of hydrangeas.

What is Ericaceous Compost?

Ericaceous plants enjoy soil that is lime-free and high in acid-promoting organic matter. As a highly acidic mix that’s formulated for lime-hating plants such as hydrangeas.

Azaleas, rhododendrons and camellias all thrive in acidic soil. If the soil is too alkaline, gardeners use soil amendments including special composts that acidify the soil.

Ericaceous compost is often fortified with vitamins and other nutrients to support healthy plant development and spectacular blooms.

Benefits of Ericaceous Soil on Hydrangeas

Apart from altering the pH of the soil so that it fits the needs of hydrangeas, ericaceous soil has other benefits as well:

  • It adds organic matter to the soil improving its quality and drainage
  • Ericaceous soil that’s fortified with zinc complex helps build resilience
  • Ericaceous compost fortified with iron promotes rich green leaves
  • Some formulations help retain moisture much better
  • Other formulations focus on strong root development or rapid growth
  • Pink hydrangea blooms can be turned to blue because of the change in the soil’s acidity

Therefore, acidic soil and blue blooms are common benefits of all ericaceous soil, however, different formulations have different other benefits to your hydrangeas.

Best Ericaceous Compost for Hydrangeas

Before I show you an easy way to make your own ericaceous compost, I’m quickly going to review some of the best commercially available ericaceous composts.

I’ve picked three that I believe have the best formulations for hydrangeas:

– Miracle-Gro Ericaceous Compost

Enriched with Miracle-Gro plant food, this ericaceous compost has a special formulation that acts in the following ways:

  • The iron fortified compost produces greener leaves
  • The 14 minerals added to the compost help stronger and faster growth
  • The Fibre Smart Technology creates a perfect balance of air and water, stimulating healthy and strong root growth
  • The Smart Waterlock Technology increases water absorption of the compost by 25%.

Therefore, the Miracle-Gro compost not only creates a favorable soil for hydrangea growth but also acts on multiple levels of plant development from roots to foliage.

Another benefit of this formulation from Miracle-Gro is the enhanced growth of your plants. The product claims to grow plants twice as big.


– Westland Ericaceous Planting & Potting Mix

This planting and potting mix from Westland has been specially blended for acid-loving plants such as hydrangeas, azaleas, and camellias.

The benefits of this ericaceous blend are the following:

  • Contains 6-month slow-release feed for sustained development
  • Rich in iron for greener leaves
  • The added zinc complex improves the plant’s ability to fight diseases and bounce back to health

Formulated to maintain an acidic environment for hydrangeas, the Westland ericaceous potting mix is a complex and complete soil amendment for acid-loving plants.


– Westland Gro-Sure Ericaceous Compost

A different blend, also from Westland, is the Gro-Sure ericaceous compost that contains a 4-month feed for hydrangeas to ensure longer flowering and more beautiful blooms.

The Gro-Sure can be used with excellent results for potted plants or flower beds containing acid-loving plants.

The iron in the composition of the compost ensures more beautiful foliage growth. While the patented West+ fiber added to the blend helps with moisture retention.

Overall, the Gro-Sure helps the plant develop stronger roots, offers better moisture control and enhances bloom production.


Making The Soil Acidic (without using a special compost)

If you don’t want to use a commercially available ericaceous compost or a soil amendment, you can either create your own ericaceous potting mix or use coffee grounds to create a more acidic soil environment for hydrangeas.

Here’s how you can create your very own ericaceous potting mix:

  • Start with a base of health peat moss
  • Add 20% perlite and 10% of each of the following: compost, garden soil, and sand.

Alternatively, you can create an ericaceous compost yourself by setting up a compost pile. If you have the time and curiosity, here’s how to make an acidic hydrangea compost:

  • Start out with a layer of organic matter that contains oak leaves, pine needles and coffee grounds
  • Sprinkle dry fertilizer formulated for acid-loving plants over the layer of organic matter being careful not to add more than 1 cup per square foot
  • Add a layer of garden soil to help with the decomposition
  • Alternate the layers and water between layers until you have a compost pile of around 5 feet.

You can also use spent coffee grounds by adding them directly to the soil of hydrangeas, although using coffee grounds in compost can unlock more benefits.

It’s important to measure the soil acidity to see whether it needs amending or not. For blue flowers, hydrangeas require a soil pH of 5.5 or lower.

To assess the soil acidity, I use the Sonkir Soil pH Meter. It’s a reliable tool that will help you make the determination to add ericaceous compost to your hydrangeas or not.

I enjoy this ph meter in particular because it has a triple function — it detects soil pH value, soil moisture level and sunlight level.

pH meters are an indispensable tool in any gardener’s toolkit and the Sonkir soil pH meter goes beyond determining soil pH value, it also determines soil moisture and sunlight level.

Wrap Up

Ericaceous compost is an extremely beneficial addition to your hydrangeas, whether because you want to manipulate bloom colors or you simply want to improve the health and vigor of your plants.

These composts are enhanced with plant feed, iron, zinc and a few patented moisture retention mechanisms that acting together will help hydrangeas go through spectacular growth and health.

Whether you choose a commercially available blend or you create your own blend, your hydrangeas and other acid-loving plants will be thankful for it.

Hydrangeas   Updated: May 30, 2022
avatar Hi, I'm Amy, a devoted horticulturist and the creator of, where I use my expertise to help beginners foster their green thumbs. My blog is a vibrant community where I unravel the complexities of gardening and share my profound love for nature.
Leave a Comment

Your email address will not be published. Required fields are marked *