A TikTok horticulturalist has revealed that adding coffee grounds to soil can turn hydrangeas the 'deepest blue' and encourage more blooms. Brittany, known as 'allegedlybrittany', shared a video showing the dramatic difference between hydrangeas treated with coffee grounds and those without.
How Coffee Grounds Affect Hydrangeas
Coffee grounds increase soil acidity, lowering the pH level. This allows hydrangeas to absorb aluminium from the soil, triggering a chemical process that turns the petals blue. The method works best on lacecap, bigleaf, and mophead varieties. Oakleaf and smooth hydrangeas, such as Annabelle, will not change colour.
In the TikTok video, Brittany displayed hydrangeas that had not received coffee grounds: they had a pleasant hue but lacked blooms and appeared small. In contrast, the treated hydrangeas showed a stunning range of blue shades, from light to intense, and were significantly larger with abundant blooms throughout her front garden.
Reaction from Gardening Enthusiasts
The video garnered over 145,000 likes and prompted many questions. User Strawberri95 asked: 'I've not heard of this. How does it work? Do you sprinkle the grounds on the soil at the bottom of the plant? Or mix it with the soil?' Beth Dunn responded: 'Sprinkle and water would work. You can also pour old coffee on the roots. The acidity changes the bloom colour and makes them bloom better.'
Alice Benson explained: 'It adjusts the level of the soil's pH. Acidic soil promotes blue or lavender blue blooms, while alkaline soil encourages pink or red.'
Additional Gardening Tips
Hydrangeas are beloved UK garden plants that can flower for months annually with proper care. Using coffee grounds is an easy, cost-effective method to enhance colour and blooming. However, gardeners should note that this technique only works on specific hydrangea types.
