Are you a coffee drinker and a gardener? If so, you are in luck! Used coffee grounds are fantastic for the garden. It is a great way to reuse and repurpose the remnants from our morning caffeine imbibing. Spent coffee grounds are a free fertilizer additive that shouldn’t be thrown away.
Why Are Coffee Grounds Good For the Garden?
Used coffee grounds assist in the retention of nitrogen which is something that all plants need in order to grow well. Nitrogen is a building block in the plant world. Coffee grounds act as a slow-release fertilizer, giving nitrogen, potassium, and magnesium to the soil and helping the plants grow stronger.
The addition of coffee grounds also increases the fertility and texture of the soil which attracts earthworms and beneficial microorganisms. Earthworms break down organic matter into elements that plants can absorb. They also increase the amount of air and water that remain in the soil. Earthworm castings (poop) are an incredible fertilizer on their own, so anything that attracts them is hugely beneficial.
What Plants Benefit From Used Coffee Grounds?
In short, all plants can benefit. There are folks who say the coffee grounds are too acidic to add to all plants, however, that doesn’t hold true. Fresh coffee that hasn’t been brewed is super acidic, which is where this idea comes from. Used coffee grounds lose the acidity and in general have a neutral or close to neutral pH. This means they can be added as a fertilizer for all plants.
How Do I Add Coffee Grounds to my Garden?
There are several methods for adding coffee grounds. The easiest method is to brew your coffee in an unbleached, compostable filter and then deposit the entire thing in the garden, filter and all. The grounds can literally go from the coffee maker to the garden without any steps in-between.
When adding coffee grounds straight into the garden, sprinkle the grounds around thinly and cover them with soil. Do not dump large amounts in places as they will actually clump together and block water from reaching the plants. They need to be spread lightly and mixed in to be effective.
For the best results, add the coffee grounds in small amounts around the plants and see how they do. Start with ¼ cup once a week for several weeks and then evaluate the plant growth. Use less or more depending on the results.
The grounds can also be mixed with water and sprayed or poured on and around the plants. A good ratio is one part grounds to 5 parts water.
Another great way to use coffee grounds is to make your own super-rich potting soil. Mix equal portions of used coffee grounds and topsoil and add it to your garden. As mentioned before, don’t add a thick layer as the grounds can clump together and prevent water absorption.
If you have a compost bin or pile, you may already be adding your coffee grounds in there. This is also an effective method. It will take longer for the garden to receive the nutrients since compost takes time to develop, however, it will be concentrated and better broken down when it is added. Just make sure to get that compost out into the garden as a fertilizer.
Can Fresh Coffee Grounds Be Used?
Yes, you can. The grounds will be acidic, so they should only be used around acid-loving plants like tomatoes, blueberries, hydrangeas, and lilies.
Are Certain Types of Grounds Better than Others?
It does matter how the coffee is made and what type of coffee it is. In general, any type of used coffee ground will be beneficial, however, for the best results, it can be more specific.
Coffee grounds that have been boiled have lower nitrogen volumes. Drip coffee grounds are the best. Grounds from a french press are also good.
Are There Any Downsides to Adding Coffee Grounds to the Garden?
If the grounds are added too densely, it will likely hurt the garden. The coffee grounds can become like a rug on the ground and prevent the plants from breathing and absorbing air.
Do not use coffee grounds as a mulch. It seems like a good idea since they will work to prevent weeds from growing. However, the detrimental effects are much higher than the benefit when added in such high amounts. The plants will feel suffocated and it can actually prevent growth.
Can Coffee Grounds Be Used as a Pesticide?
There are a lot of gardener tales about preventing slugs, snails, and ants from invading by sprinkling coffee grounds around plants and the entire garden. I’ll save you the trouble and hope, it doesn’t work. The thing that the slugs and bugs hate is caffeine but those coffee grounds do not have enough to deter them. Even fresh grounds don’t have enough caffeine. Next time you are sitting and enjoying a nice cup of coffee, remember to save the grounds and your garden will thank you. Do we need reasons to drink more coffee? Check out our lawn care faq’s for answers to common gardening questions.