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I’m a Certified Nutrition Coach, gluten-free recipe creator, and home detoxification expert with a focus on gut health. I show burned-out women with digestive issues how to take a proactive, holistic approach to healing by sharing nutrient-dense recipes, and sustainable lifestyle tips that are easy to implement in everyday life.
Besides the warmer weather, nothing gets my heart more excited for spring as the promise of big, gorgeous blue hydrangeas in my garden. Whether you clip them for arrangements or admire them from your porch or kitchen window, there’s a reason blue hydrangeas bring so much joy–they’re simply breathtaking.
In this post, I’ll show you how to encourage your hydrangeas to bloom in heavenly shades of blue using a free, non-toxic, natural by-product: coffee grounds.
Table of Contents:
ToggleThe secret lies in the soil’s pH level. Alkaline soil leads to pink flowers, while acidic soil (containing aluminum) turns them blue. This is where coffee grounds come in—they help lower the pH naturally.
But hold that coffee filter—not all hydrangeas can turn blue.
Panicle hydrangeas (H. paniculata) produce white or green flowers, while oakleaf (H. quercifolia) and smooth hydrangeas (H. arborescens) typically bloom white, sometimes with a hint of blush.
Only bigleaf hydrangeas (H. macrophylla) are color-shifters. I grow‘Endless Summer’, an excellent choice for growing blue hydrangeas with coffee grounds. ‘Nikko Blue’ is another popular cultivar. Depending on your soil’s pH, these varieties can bloom in pink, periwinkle, or blue—sometimes all on the same plant for a gorgeous natural ombré effect (and my personal favorite).
Before you start sprinkling grounds, it’s helpful to test your soil’s pH. You can grab a simple kit online or at your local garden store—or just wing it like I did and let your hydrangea surprise you next spring.
Here’s a quick cheat sheet:
There are plenty of commercial products that will acidify your soil and encourage blue hydrangeas, but I prefer non-toxic gardening for wellness, sustainability and simplicity. Coffee grounds gently shift the pH without synthetic compounds like aluminum sulfate.
Bonus perks:
No need to baby your plants with daily doses—your hydrangea isn’t that needy, and your cup is already full (see what I did there? 😉).
Start in late fall or early spring, before new growth appears. This process is gentler than aluminum sulfate and it takes time. If your soil is highly alkaline it may take a full season before your hydrangea turns blue.
Keep in mind, this method won’t affect existing blooms—only new ones. Continue monthly during the blooming season to encourage blue blooms and enjoy the variety of colors throughout the process!
Rather than just another task, make feeding your hydrangeas a mindful ritual. A ritual is anything done with intention.
I like to collect my coffee grounds throughout the week and head outside Saturday or Sunday morning, barefoot, to feed the soil. I listen to the birds, put fresh homemade hummingbird food in my feeder, feel the sun on my skin, and offer a little gratitude as I scatter the grounds. It only takes a minute or two—but it roots me in the moment and sets a calm, grounded tone for the day.
Come May, when those first buds pop and my yard is full of periwinkle blue hydrangeas, I feel so much joy.
Use a natural soil acidifier, such as coffee grounds to reduce the pH of your soil to 5.2-5.5 for blue hydrangea blooms.
The pH of your soil determines whether your bigleaf hydrangea produces pink, periwinkle or blue blooms. Acidic soil (5.2-5.5 pH) produces blue flowers, while alkaline soil (pH over 7.0) results in pink blooms.
🔹 Don’t forget to save this natural gardening tip on Pinterest so you can enjoy blue hydrangeas all summer!
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