Nothing is better in winter than a sharing a nice, hot cup of coffee with good company. The joy of coffee doesn’t end there because the gift of coffee keeps on giving! Coffee grounds are fantastic to use in the garden though like with most things in life, don’t go overboard and use in moderation. Most experts agree that some coffee grounds in your garden can be beneficial when used in your compost bin and sparingly as a fertilizer.
In your compost bin it is recommended that 10 to 20 percent of your compost total should be made up of coffee grounds. When you make coffee grounds compost you need to think of the coffee grounds as a compost green. (Similar to freshly cut grass) About 2 percent nitrogen by volume used coffee grounds can also be a safe substitute for nitrogen-rich manure in the compost pile. Some evidence also suggests that worms are very attracted to them so you can use them in vermiposting (worm bin) situations if you want to.
As a fertilizer try not to lay the grounds too thick in your garden, as certain types of plants won’t like them at all. The benefit of using coffee grounds as a fertilizer is that it adds organic material to the soil, which improves drainage, water retention and aeration in the soil. Plants like Azaleas, Gardenias, Hydrangeas, Roses, Rhododendrons, and Blueberries all seem to respond well when grounds are mixed in with their soil. Most edible garden crops also prefer slightly acidic soil, but adding coffee grounds also seems to affect them in different ways. For example, lettuce seems to love coffee grounds, but tomatoes don’t and can be badly affected by the grounds. Researchers are not exactly sure why some acid-loving plants respond differently to fresh grounds than others, but it could be because coffee contains chemicals that stop growth in some plants. This might be helpful when you’re trying to control weeds, but unfortunately, coffee grounds can’t tell the difference between the plants you like and the plants you don’t.
A word of caution on using coffee grounds for houseplants: Moist grounds encourage fungus growth that can be detrimental to your plants. If you use them on houseplants, use only a little and avoid watering your plants unless the soil is dry to the touch. (I learnt this the hard way last year and my indoor plants are still slowly recovering!)
So next time you have a steaming cup of coffee remember to save the grounds or if you are at café ask if you can take some grounds home in a plastic bag. You are not only saving the grounds from landfill but also providing extra nutrients to your garden, Now doesn’t that make your next cup seem even more tempting?