Coffee Grounds in the Garden:The Benefits and How to Use ThemFirst up, coffee grounds make a great fertilizer for your plants They’re high in nitrogen, phosphorus, and potassium, which are essential for plant growth.coffee grounds can be used to repel pests like ants, slugs, and snails. Simply sprinkle them around the base of your plants to create a barrier.And finally, coffee grounds can be added to your compost pile. They’re a great source of organic matter and can help balance the pH level of