Coffee Grounds In Your Garden !

If you are trying to keep up with the garden trends this year or are perhaps looking to recreate the wildflower garden border trend then coffee grounds are a great plant fertiliser.

Russell Birchell, Founder of ‘Hedging UK’ says, “Coffee grounds imbue the soil with vital nutrients such as potassium, nitrogen and phosphorus, leading to healthier plant growth and greater blooming potential in the long run.”

When it comes to how you should spread your coffee grounds and how often there’s a little more choice to it than simply dumping the grounds into your soil and calling it a day.

“Coffee grounds can be used in various ways in the garden, ” agrees Peter Ivanov, Professional gardener at ‘FantasticGardeners’. “For example, they can be incorporated into compost bins or worm bins to add nitrogen and increase microbial activity, which will make them more nutrient-rich.”

If you don’t have a compost bin then you can also use the grounds directly as a mulch around acid-loving plants, explains Peter. Plants such as azaleas, rhododendrons, blueberries and roses are particularly fond of acidic mulch as they naturally help lower soil pH over time.

Peter also suggests mixing the grounds into the soil as this can improve soil structure and drainage, however, he does warn against overuse as they are not compatible with every plant species.

“It’s not suitable for all plants and the main problem is that if they’re applied in a larger quantity to the top of the soil, their small particles can clump together and prevent water and air from reaching the roots of the plants,” explains Peter.

To prevent this he recommends using the coffee grounds on the border soil of established plants only and making sure you aren’t putting them in the same spot every time. 

“Coffee grounds can act as a great deterrent for slugs and snails because the rough texture of them can irritate their soft bodies, making it uncomfortable for them to crawl across the soil,” It’s not just the texture of the grounds however, the actual caffeine content is also believed to have a toxic effect on slugs and snails too.

Peter does point out that the grounds alone won’t completely deter the plant-eating pests, and suggests using them alongside other types of barriers and traps too. The grounds as pest control will also need to be applied often as they will deteriorate, especially if it’s rained recently.

Although adding coffee grounds is one of the easy gardening tips that every gardener should know, there are a few do’s and don’ts. Due to the acidness of the grounds, there are some plants you should not be putting them anywhere near for example tomato plants and seedlings as this can interfere with their growth and germination. 

“It’ll be best to compost them first to reduce their acidity and allow them to break down, making them suitable for a wider range of plants,” explains Peter. Once you’ve composted your grounds then they should be safe to use for the rest of your plants and flowers, but you must add the grounds gradually.

Peter warns of creating a water-restricting barrier with the grounds which could eventually cause your plants to wilt and die. He recommends adding a layer of another type of organic mulch, such as wood chips, just to stop the grounds clumping together and stop water movement.