Our love for fine coffee generates a whole lot of smiles … and great big piles of used coffee grounds. If you’re reading this blog, we’re guessing you have the same situation at home.
Wondering what to do with all that good grit once your brewing is through? Take it outdoors, and your plants will thank you -- as long as you use moderation.
Ask any local farmer or master gardener: Some plants will be much more sensitive to caffeine than others. Too much coffee may inhibit plant germination and growth. Fine coffee particles can also lock together into a clay-like barrier that resists moisture penetration, leaving plants dried out and thirsty.
The bottom line is that applying a thick layer of used coffee grounds directly around plants and seedlings is just too much of a good thing. The acidity in coffee can vary widely, which affects soil pH levels and is another reason why a light touch is best.
The good news is coffee grounds contain strong amounts of essential nitrogen, as well as potassium, phosphorus, and other micronutrients that plants love.
To reap these benefits, the best approach is to temper the intensity of caffeine and acidity by adding used coffee grounds to a compost pile. Mixing your old grounds with other organic matter helps to draw out valuable nutrients that are imparted to the final compost. Balance coffee with dry, carbon-rich materials like grass clippings or newspaper, and rake the pile thoroughly to prevent clumping.
If you are not composting right now, but you still want coffee to enhance your garden, it’s okay to sprinkle used grounds thinly around well-established plants. Just be sure to use it sparingly, and mix everything well with the existing soil. In this way, your coffee grounds act as a kind of slow-release fertilizer.
Not big on gardening at home? You can bag up some used coffee grounds to share with a neighbor or community garden, and help others as they grow.