Whenever I brew freshly ground coffee in a cafetiere, it always feels so wasteful to be throwing something so pure and natural away after so little use.
Before we moved house, we used to just dump all of the used coffee grounds into the compost bin, that seemed to work fine.
But since moving house, we no longer have a compost bin and now I am wondering what can I do with all the used coffee grounds, besides putting them in the bin? I wondered if coffee grounds are good for the garden, do they provide nutrients for garden plants and help to fertilise the soil?
What Are Coffee Grounds Good For?
Coffee grounds are excellent for some plants in the garden; they give fast- maturing vegetables and acid-loving plants a boost by giving them extra nitrogen.
However, used coffee grounds are not as acidic. After they have been brewed, the water will neutralise them, leaving them with a near neutral pH balance of around 6.5.
There are still benefits to using leftover coffee grounds in your garden though, regardless of the pH level, to help create a nutrient rich soil.
Three Ways to Use Your Used Coffee Grounds in the Garden
1. Put Your Used Coffee Grounds in a Compost Bin
Throwing your coffee grounds into the compost bin is the easiest way to put your coffee grounds to good use, quickly and easily.
Adding coffee grounds to a compost bin helps to add nitrogen the pile.
Coffee grounds are also a great source of food for worms, if you get worms into your compost bin, they do an fantastic job of helping to create the most beautifully rich and soft compost.
2. Use Your Coffee Grounds as a Fertiliser
By adding coffee grounds directly to the soil, there will be a slow release of nitrogen.
The main reason why coffee grounds are good to add to soil is that by adding organic material to the soil, you will improve drainage, as well as water retention and the aeration of the soil.
The coffee grounds also help microorganisms that are beneficial to plant growth thrive, (coffee grounds also attract earth worms – a good thing!)
How do I add the coffee grounds to the soil?
You can work the coffee grounds into the soil around the plants, using a fork or even just your hands. If you’re lazy, sprinkling them on top and watering them in will also work (just maybe not as well, because the goodness has further to go down to get the roots.)
You can also pour leftover diluted coffee directly onto the soil too.
3. Using Coffee Grounds for Acidic Benefits of Garden Plants
Some fast maturing vegetables and acid loving plants get a boost from coffee grounds because they provide extra nitrogen.
To use coffee grounds to lower the pH level (or raise the acidity level) of soil, the coffee grounds must be unwashed but not have been brewed. Washing or brewing the coffee grounds with water raises the pH level of the grounds and reduces the acidity level. Used coffee grounds will have a pH level of near neutral, (around pH 6.5).
So this is not an option for your used coffee grounds.
But – if you have a large pack of coffee beans or grounds that you want to get rid of, simply sprinkle them around acid loving plants in your garden to give them a boost.
Plants to Use Coffee Grounds On
- Hydrangeas – acidic soil ca help to turn the flowers from pink to blue. (The colour of the flower depends on the acidity of the soil.)
- Azaleas – using coffee grounds on azaleas will help to promote blooms and vibrant colour.
- Roses – Apply coffee grounds conservatively to roses, for a nitrogen boost. (Roses don’t like the soil too acidic and using too many coffee grounds could damage the plant, use sparingly and assess.)
- Lettuce and Tomatoes – Use coffee grounds to provide these plants with more nitrogen. You can also make a ring out of the coffee grounds around the plants, to deter pests such as slugs and rabbits.
- Blueberries – Blueberries grow better in soil that is more acidic. Apply coffee grounds thinly around bushes to boost fruit production and to deter pests.