How to Make Hydrangeas Blue By Adding Aluminum Sulfate to Soil

​Greetings, fellow garden enthusiasts! If you’ve ever found yourself mesmerized by the stunning blue hues of hydrangea blooms and wondered, “How can I make mine look like that?” – you’re in the right place! 

Today, we’re diving into the captivating world of hydrangeas and the secret ingredient to turning them into a brilliant sea of blues: aluminum sulfate. Whether you’re a seasoned gardener or just getting started with your green thumb, the quest for that perfect pop of color in your garden is a universal pursuit. 

Hydrangeas, with their lush clusters of blossoms, are known to steal the show, but did you know that you can actually influence the color of these beauties with a simple soil amendment? Yes, it’s true – and the magic lies in the power of aluminum sulfate. 

In this blog post, we’ll walk you through the easy steps of transforming your hydrangeas into a mesmerizing display of blue. 

No need for complicated jargon or advanced gardening degrees – we’re keeping it simple, so everyone can enjoy the thrill of creating their own blue oasis. So, grab your gardening gloves and let’s embark on this colorful journey together!

Why Aluminum Sulfate Is Necessary

​If you want to make hydrangeas blue, you need to use aluminum sulfate. This is because aluminum sulfate helps to lower the pH of the soil, making it more acidic. The more acidic the soil is, the deeper blue the hydrangeas will be.

Aluminum sulfate is also necessary for hydrangeas because it helps to provide them with the aluminum they need to grow. Aluminum is an essential nutrient for plants, and without it, they will not be able to thrive.

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So, if you’re looking to make your hydrangeas as blue as possible, be sure to use aluminum sulfate. It’s the key to getting those beautiful, deep blue blooms!

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How Much Aluminum Sulfate to Add to Make Hydrangeas Blue

​If you want stunning blue hydrangeas, then you need to use the right soil. Aluminum sulfate is the best way to create the perfect environment for these flowers. Here is everything you need to know about how much aluminum sulfate to add to make hydrangeas blue.

When it comes to soil, hydrangeas are picky. They prefer soil that is acidic, with a pH of 5.5. This can be achieved by adding aluminum sulfate to the soil. But how much aluminum sulfate should you add?

The amount of aluminum sulfate you need to add to the soil depends on the current pH of the soil. If the soil is already acidic, then you will only need to add a small amount of aluminum sulfate. However, if the soil is neutral or alkaline, then you will need to add a larger amount.

To figure out the right amount of aluminum sulfate to add, you will need to do a soil test. This will tell you the current pH of the soil. You can then use this information to figure out how much aluminum sulfate to add.

Once you know how much aluminum sulfate to add, you can apply it to the soil. It is best to apply it before planting the hydrangeas. You can either sprinkle it over the soil or mix it in.

Be careful not to add too much aluminum sulfate to the soil. If you do, it can damage the roots of the plants. It is also important to water the soil after adding aluminum sulfate. This will help to prevent root burn.

Now that you know how much aluminum sulfate to add to make hydrangeas blue, you can enjoy these beautiful flowers in your garden.

Caring for Hydrangeas With Aluminum Sulfate

​Hydrangeas are one of the most popular flowers in the world. They are beautiful, versatile, and easy to care for. One of the most common questions about hydrangeas is how to keep them blooming blue.

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The answer is simple: aluminum sulfate.

Aluminum sulfate is an inexpensive, readily available product that you can find at most garden centers. It is the key to keeping your hydrangeas blue.

Here are some tips for using aluminum sulfate:

  • Apply it to the soil around your hydrangeas once a month.
  • Be sure to wear gloves when handling aluminum sulfate, as it can be irritating to the skin.
  • When applying aluminum sulfate to the soil, be sure to water it in well.

By following these simple tips, you will be able to keep your hydrangeas blooming blue all season long!

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Potential Problems With Aluminum Sulfate

​If you’re looking to add aluminum sulfate to your soil in order to make your hydrangeas blue, you may want to reconsider. Although aluminum sulfate can indeed make hydrangeas blue, there are a few potential problems that you should be aware of before using it.

One potential problem with aluminum sulfate is that it can make the soil too acidic. If your soil is already on the acidic side, adding aluminum sulfate can push it too far and make it difficult for other plants to grow.

Additionally, aluminum sulfate can bind with other minerals in the soil and make them unavailable to plants. This can lead to deficiencies in important nutrients like calcium and magnesium.

Another potential problem with aluminum sulfate is that it can be harmful to aquatic life if it leaches into waterways. When used as directed, aluminum sulfate should not pose a risk to waterways.

However, if you live in an area with heavy rains, there is a risk that the aluminum sulfate could leach out of the soil and into waterways, where it could be harmful to fish and other aquatic creatures.

If you decide to use aluminum sulfate to make your hydrangeas blue, be sure to use it sparingly and only in well-drained soil. By doing so, you can help minimize the potential problems and ensure that your plants get the nutrients they need.

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How to Make Hydrangeas Blue By Adding Aluminum Sulfate to Soil


​In conclusion, you can make hydrangeas blue by adding aluminum sulfate to soil. This will change the pH of the soil and make the flowers blue.

It is essential to know the right amount of aluminum sulfate to add to the soil. The general rule is to use two tablespoons of aluminum sulfate per gallon of water. Then, apply the solution to the soil around the base of the plant. Be sure to water the plant thoroughly after applying the solution.


Why do hydrangeas turn blue with aluminum sulfate?

Hydrangea flowers change color based on the pH of the soil. Aluminum sulfate increases soil acidity, encouraging the plant to absorb aluminum. This aluminum uptake is what turns the hydrangea blooms into that beautiful shade of blue.

When is the best time to add aluminum sulfate to the soil for blue hydrangeas?

The ideal time to add aluminum sulfate is in the early spring before the hydrangea starts actively growing. This allows the soil to adjust gradually, influencing the color of the upcoming blooms.

How much aluminum sulfate should I use?

It’s crucial to follow package instructions, but as a general guideline, one to two tablespoons of aluminum sulfate per gallon of water is a common recommendation. Be cautious not to overdo it, as excessive amounts can harm the plant.

Can I use aluminum sulfate on any type of hydrangea?

Aluminum sulfate is most effective on mophead (Hydrangea macrophylla) and lacecap hydrangeas. Other varieties may not respond as dramatically to changes in soil pH.

How long does it take for hydrangeas to turn blue after adding aluminum sulfate?

Patience is key! It may take a growing season or two to see significant changes in bloom color. Be consistent with soil amendments and monitor the pH regularly.


Hello, I'm Kenneth C. Sather, the Head Content Writer at Aker Kits, a thriving urban gardening blog. With a passion for cultivating green spaces within the urban jungle, I strive to connect with our readers through insightful and engaging content.

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