The secret ingredient to help your roses thrive this summer is going to waste in your kitchen – this is how to use this free trick for bigger, better blooms
Experts say they can be beneficial, but only if you use them correctly
If you've ever wondered whether roses like coffee grounds, the answer is yes, but only when they're used in moderation.
Coffee grounds have long been recommended as a free, eco-friendly way to feed plants, and while roses are included on lists of plants that love coffee grounds, experts say there's a right and wrong way to use them. Adding too much can actually create problems for your roses, even though this is a really popular gardening hack.
While you might want to throw it straight from your coffee machine's grounds container, it's worth noting that there are places you should never put coffee grounds in your garden, as some plants and soil conditions simply won't respond well to them.
'Coffee grounds can be used on roses, but only in the right way,' explains Jo McGarry, a leading expert in garden design from Caragh Nurseries. They're not a magic fix, but they can be useful in small amounts.' And here's why and how to use them correctly to benefit your roses.
Why coffee grounds can help roses
One of the main reasons gardeners use coffee grounds on roses is that they can improve soil health.
As Jo explains, you'll often notice more worms where coffee grounds have been used, which is a positive sign for soil quality. 'You'll also often notice more worms, which is always a good sign, and roses do tend to like that kind of healthy soil.'
Gardening expert Lucie Bradley from Easy Garden Irrigation says used coffee grounds can benefit a wide range of garden plants, from acid-loving favourites such as azaleas, lilies and lupins to hungry plants like begonias and roses.
If you're learning how to grow roses successfully, feeding is one of the most important things to get right. Roses are particularly demanding plants that need a steady supply of nutrients throughout the growing season. Lucie explains that nitrogen is especially important because it helps produce strong stems and healthy foliage, which ultimately fuels flower production.
'Being able to recycle your coffee grounds to boost nitrogen for your roses is a simple, free way to help them without having to rely solely on chemical fertilisers,' she says.
She adds that coffee grounds provide not only nitrogen but also smaller amounts of potassium, phosphorus and micronutrients, including calcium, copper and magnesium. Added to the soil, they act as a slow-release fertiliser, gradually releasing nutrients over time.
Richard Barker, Horticulture expert at LBS Horticulture, also highlights that they help feed beneficial soil microbes, improving overall soil health and making nutrients more available to plants.
The coffee ground mistake gardeners make
The biggest misconception is that more coffee grounds equal healthier roses.
In reality, adding too much can cause problems. Richard warns that coffee grounds left sitting on the soil surface can lock together and form a water-resistant layer, making it harder to penetrate the soil.
To avoid this, he recommends using coffee grounds sparingly and working them into the soil rather than leaving them on the surface.
Jo agrees with this advice. 'If you're going to use them, I'd go easy. A light sprinkle around the base now and then is fine, or even better, pop them in the compost first so they've had a chance to break down properly.'
How to use coffee grounds on roses
Lucie recommends allowing used coffee grounds to dry completely before applying them.
'The best way to add used coffee grounds into the soil to help your roses is to first let them dry completely so that you are able to sprinkle them over the soil rather than using them as soggy clumps,' she explains.
Once dry, she recommends applying up to two tablespoons per plant around the base of the rose, taking care to avoid the main stem.
After sprinkling the grounds around the plants, gently work them into the top 10cm of soil with a hand rake and water thoroughly. This helps speed up decomposition, so the nutrients become available more quickly.
Lucie also says you can create a liquid feed by steeping used coffee grounds in water overnight and using the resulting 'coffee tea' around the base of your roses.
Is it better to compost coffee grounds first?
According to the experts I spoke to, composting coffee grounds is often the safest option. Adding them to your compost heap allows them to break down fully before they're applied to your borders, while also helping you make use of kitchen waste that would otherwise be thrown away.
Once composted, coffee grounds can be used around roses as part of a nutrient-rich homemade compost.
What else should you feed roses?
While coffee grounds can provide a small boost, the experts don't necessarily recommend relying on them as your main rose fertiliser.
'But if you want really good roses, coffee grounds are just a small part of it,' explains Jo. 'A proper rose feed in spring will always do more for growth and flowering.'
Richard recommends using a slow-release granular rose fertiliser, like Miracle-Gro's Rose & Shrub continuous release plant food, £8.49 at Amazon, in spring before new growth begins. Throughout the growing season, liquid seaweed feed, like Envii's SeaFeed Xtra, £13.95 at Amazon, can strengthen roots and improve plant resilience, while tomato feed can encourage stronger flowering thanks to its potassium content.
Jo is also a fan of organic soil improvers. 'Well rotted manure, like Westland's farmyard manure, which you can pick up at Amazon for £13.99, is also a really good option because it feeds the plant slowly while improving the soil at the same time. Seaweed feed is another useful choice if you want something a bit gentler through the growing season.
Lucie adds that banana peels can also be repurposed as a natural source of potassium for flowering plants, such as roses.
Shop rose-feeding essentials
So there you have it. Coffee grounds can certainly benefit roses, but they aren't the miracle ingredient they're sometimes made out to be.
Used occasionally, they can improve soil health, support beneficial microbes and add organic matter to your borders, but they're best used alongside a proper rose-feeding routine.
As Jo puts it: ' Once your soil is in good shape, roses are actually pretty straightforward to grow. Coffee grounds are a nice extra, but they're definitely not the main thing.'
