The TikTok gardener showed the video with her thousands of followers10:06, 01 Jun 2026Hydrangeas are beloved garden plants across the UK, coming in an array of colours. When properly tended, they can flower for months on end each year. According to one gardener, you can effortlessly make hydrangeas "bloom better" and alter their colour by adding a kitchen scrap to the soil.‌Taking to TikTok to reveal her gardening trick, Brittany, who goes by the username allegedlybrittany, posted a video of her hydrangeas to her 28,000 followers. In the revealing clip, the gardener displayed her flowers: some had received kitchen scraps, and some had not, and the outcomes were striking.‌The caption of the video said: "This is the difference between using coffee grounds and not. The deepest blue I've ever seen."‌Initially, the TikTok gardener showcased the hydrangeas, which hadn't received any coffee grounds. While they were an attractive colour, they lacked blooms and were modest in size.The video then swept around to the opposite side, where the hydrangeas had been treated with coffee grounds. They were a stunning shade of blue, some paler and others richer.‌They were also considerably larger, displaying plenty of blooms in her front garden.Coffee grounds help turn hydrangeas blue by raising soil acidity, which enables the plant to take up aluminium.When soil is acidic and low in pH, the flowers can readily absorb aluminium from the soil, triggering the chemical reaction that turns the petals blue. It's worth noting that this trick only applies to certain varieties, such as lacecap, bigleaf and mophead hydrangeas.‌Varieties, such as oakleaf or smooth hydrangeas, including Annabelle, will never produce blue blooms.The clip, which garnered more than 145,000 likes, sparked a tremendous reaction from fellow gardening enthusiasts, who were left thoroughly impressed by the outcome.User Strawberri95 said: "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?"Article continues belowBeth Dunn replied: "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 commented: "It adjusts the level of the soil's pH. Acidic soil promotes blue or lavender blue blooms, while alkaline soil encourages pink or red."