Guest blogger William Habblett
Harmony Landscape and Design, llc
Did you know coffee is good for us? Well, I don’t know about it being ingested; I’m a horticulturist, not a health practitioner, so I will leave that discussion up to you and your health care practitioner. When it comes to the garden and plant beds, coffee grounds can be you and your plant’s new best friend. Not to mention, that it is a great way to recycle coffee grounds if you are not set up for composting in your landscape.
A few years ago, I started listening to people using coffee grounds around their blueberries and other acid loving plants, and they were touting how great their plants were doing. Well, the scientific data doesn’t necessarily support the acidic action to the soil profile. It would most likely only be in the immediate area of the grounds themselves. However, that doesn’t mean that there aren’t some great benefits to laying out the coffee grounds.
Coffee grounds themselves are comprised of nitrogen rich proteins, lipids, fatty acids, and cellulose that are great for your plants and the soil environment that they are added to. Over time, beneficial fungi and bacteria break down the different compounds for plant availability and improve microorganism soil life. It also increases the availability of soil bound nutrients such as phosphorous, zinc and iron –alleviating a common problem in our alkaline soils.
It has also been found that coffee grounds are a viable food source for earthworms. Earthworms will pull coffee grounds deeper into the soil, which may assist in soil structure. By moving humic (organic) substances into the soil profile, earthworms increase nutrient availability.
Sounds great, right? Now before you run out and throw coffee grounds on everything, a couple words of caution. Fresh coffee grounds can be phytotoxic, so don’t mix into the soil or apply on bare roots. Apply a thin layer on top of the soil, like mulch, and let the grounds and micro life do their thing. You don’t want to apply this to your seed beds. Coffee grounds that haven’t been composted can impact soil germination and initial plant growth, so spread this out when your plants are already growing. You don’t want to apply coffee grounds any thicker than a half inch deep to your beds. They are such a dense binding material that they can cause the surface to become hydrophobic and inhibit air or water intake into the soil.
So, while you are enjoying your daily brew, now you have a great way to rid of the evidence and help your garden and landscape beds. And another great note, there is evidence that shows that coffee grounds bind with pesticides and heavy metals which prevents their movement into the surrounding environment.