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What do I add to hydrangeas to make them blue?

Author

Emma Payne

Published Feb 22, 2026

What do I add to hydrangeas to make them blue?

Adding dried coffee grounds to the soil around hydrangeas increases the acidity of the soil, which boosts the blue-producing capabilities of the hydrangea and the ability to absorb aluminum from the soil. Monitor the pH level of the soil over time with a pH test kit; a range of 5.2 to 5.5 is best for blue blooms.

In respect to this, how do I make blue hydrangeas with vinegar?

For each gallon of water in your watering can, add one cup of white distilled vinegar and pour on your hydrangeas. The acidity of the vinegar will turn your pink hydrangeas blue or keep your blue blooms from turning pink. To lower the acidity of your garden's soil, ask your local nursery for limestone.

Secondly, what do you feed a hydrangea to keep it blue? Ericaceous Compost is ideal.

So, to make sure your hydrangea stays really blue add Vitax Hydrangea Colourant, a powder containing aluminium that you can mix with the growing medium when you plant. You can also mix a little into the soil surface each spring and add it to the can when you water your plant.

Similarly, you may ask, do coffee grounds make hydrangeas blue?

Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum.

Does Epsom salt turn hydrangeas blue?

Epsom salt comes from the reaction of magnesium metal and sulfuric acid. Since the blue color of a hydrangea is formed by aluminum made available in acid soil, adding Epsom salt would not make your flowers change color.

Does apple cider vinegar turn hydrangeas blue?

There is one more trick up the apple cider vinegar sleeve: You can actually change the color of hydrangea flowers from pink to blue. Hydrangea flowers will be pink in alkaline soil, but change to blue in acidic soil. So, mix up some apple cider vinegar and water, and give all the acid-loving plants a treat.

What do you put in the soil to change the color of hydrangeas?

Alkaline soil, with a pH above 7.0, promotes pinks and reds. With a pH between 6 and 7, the blooms turn purple or bluish-pink. To lower your pH, add garden sulfur or aluminum sulfate to your soil. To raise the pH, use ground lime.

How do you turn green hydrangeas blue?

A high pH makes the soil more alkaline, which will color the hydrangea blooms pink. A low pH makes the soil more acidic, which turns the hydrangea blooms blue. You can change the color of some varieties of hydrangea by adding aluminum sulfate to make the flowers more blue, or by adding dolomite to make them pink.

Is Baking Soda Good for hydrangeas?

Baking soda is one of the recognised ways to change the color of hydrangeas. It will alter the pH level in the soil and therefore change the bloom color. White hydrangeas are primarily grown in a neutral soil and to keep them that way, you must transplant them into a soil similar to what your plant has been grown in.

How long does it take to turn hydrangeas blue?

It is easier to change blue flowers to pink than to change pink flowers to blue, and some cultivars are more prone to color variability than others. We recommend waiting until the plant is at least 2 years old to give it time to recover from the shock of its original planting.

How do you take care of a blue hydrangea?

Hydrangea Care Tips

Water at a rate of 1 inch per week throughout the growing season.
Add mulch underneath your hydrangeas to help keep the soil moist and cool.
Apply fertilizer based on your specific hydrangeas.
Protect against pests and disease by choosing cultivars with resistant traits.

How often should I put coffee grounds on my hydrangea?

If you're looking to harness the benefits of coffee grounds related to improving the quality of the soil, you can use them in composted form 2-3 times a year. If you want to alter the pH of the soil, you may need to use them more often, scattering them over the soil of your hydrangea.

Should I deadhead my hydrangeas?

You should deadhead throughout the blooming season to keep your hydrangeas looking their beast and encourage new flower growth. However, stop deadheading hydrangea shrubs in mid to late fall, leaving any spent blooms in place.

How do you change the Colour of hydrangeas?

It is much easier to change a hydrangea from pink to blue than it is from blue to pink. Changing a hydrangea from pink to blue entails adding aluminum to the soil. Changing from blue to pink means subtracting aluminum from the soil or taking it out of reach of the hydrangea.

Can all hydrangeas turn blue?

First of all, not all hydrangeas produce blue flowers. These types of hydrangeas have the interesting ability to change the color of their blooms based on the chemistry of the soil. When grown in alkaline soil, the bloom colors are pinker. When grown in acidic soil, the bloom colors are bluer.

Why are my blue hydrangeas turning white?

If your soil is more acidic, pH around or less than 5.5, then your blue hydrangeas stay blue or bluer. White hydrangeas stay white. Don't even try to alter the soil pH to change the color.

Why has my hydrangea lost its Colour?

"Too much direct sunlight, especially in the afternoon, will cause the flower color to fade quicker than normal," she explains. "Your hydrangea should be planted in a spot that is protected from the hot afternoon sun, but still receives the cool morning sun."

How do I add coffee grounds to my hydrangea?

Simply layering the coffee grounds on top of the soil is quicker but may result in an ugly pile of mold that looks messy and smells unpleasant. Alternately, dump your coffee grounds into your compost bin and add the compost as part of your twice-yearly fertilizing ritual for your hydrangeas.

How do you keep blue hydrangeas blue?

Sprinkle elemental sulfur over the soil.

In order to keep your hydrangeas blooming in blue, elemental sulfur should be sprinkled over the soil around the shrub to lower the pH to below 5.5. The exact amount of elemental sulfur required will vary, depending on the soil type and how much the pH needs to be adjusted.

How do you care for a Nantucket blue hydrangea?

Best grown in rich, medium moisture, well-drained soils in part shade. Tolerates full sun only if grown in consistently moist soils. Soil pH affects the flower color of most cultivars except white (blue in highly acidic soils and lilac to pink in slightly acidic to alkaline soils).

When should I acidify my hydrangeas?

Timing of Application. Changing the acidity of soil can take more than just one season, although if you want blue flowers on your hydrangea, the time to add soil acidifier for hydrangeas is in the spring before flower buds form.

How do you make soil acidic for blue hydrangeas?

Adding dried coffee grounds to the soil around hydrangeas increases the acidity of the soil, which boosts the blue-producing capabilities of the hydrangea and the ability to absorb aluminum from the soil. Monitor the pH level of the soil over time with a pH test kit; a range of 5.2 to 5.5 is best for blue blooms.

How do you turn pink hydrangeas blue?

Or to transform established hydrangeas into blue beauties, apply 2½ cups of Organic Soil Acidifier. Spread evenly around the hydrangea out to its drip line, or the widest reaching branches. Then, water well. Repeat every 60 days until you've got the perfect color for you.

Are banana peels good for hydrangeas?

Banana peels also make a great fertilizer for hydrangeas. Use the peels from two or three bananas per plant. Chop the peels into small pieces and bury them around the base of each plant. Using banana peels as a fertilizer for your hydrangeas will also help to repel aphids.

How do you mix Epsom salt for hydrangeas?

So the answer is a definite maybe. The Epsom Salt Council () recommends one tablespoon per nine square feet, applied to the root zone of the shrubs at two- to four-week intervals.

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