Warrandyte Chat

Sometimes it is difficult to know how to make a difference. From the cars we drive to the food we eat and the fabrics we wear, each choice has a wide range of variation in how it impacts the environment, and keeping tabs of this can be exhausting.

I decided to do something that had an immediate and beneficial impact on the environment, cost me nothing, and made my favourite pastime of vegetable gardening even more satisfying.

Since March 2010, I have collected 850 Kilos of used coffee grounds, and it has all been used in my compost bin, dug into the raised garden beds, around the base of fruit trees, liberally sprinkled over the lawn, or handed out to family and neighbours.

You might think that coffee grounds are a weird thing to want to put into the garden, but if we go through some of the environmental benefits and physical properties of the material, it quickly makes sense why it is catching on. As the hundreds of YouTube videos attest to, you can’t keep a good secret these days.

Availability

Approximately 20 grams of coffee grounds remains every time an espresso machine is used, which is then typically thrown into the bin, and ends up in landfill.

20 grams might not seem like a big amount, until you consider that 5000 lattes work out to about 1 tonne of used grounds. Imagine all the people that stop into a cafe or use an espresso machine at home at least once a day. All those hundreds of thousands of drinks make for many tonnes of landfill each and every day.

Given there is so much of the stuff being generated, availability is not an issue. Most cafe owners would be more than happy to put some coffee grounds aside for you if you ask. One chain that actively provides this service is Starbucks, who have an initiative known as ‘Grounds for your Garden’, and if you have been in their stores over the past five years may have noticed a stack of 2 kilo bags sitting in a basket at the front of the counter.

Another way to get supply, and one of the things I do, is to arrange to collect coffee grounds generated at work. My building has at least 5 espresso machines which are emptied daily, and all the used grounds are left for me in a room in the basement car park. It took a couple of tries to get the process working, but now I’m collecting around 100 Kilos per week, thanks to all my colleagues and their love of coffee.

What is in Coffee Grounds?

There will always be variation with a natural product, and the specific contents of coffee grounds can change slightly depending on the specific origin of the beans, how they were roasted, ground, and used in the espresso machine (including the water that was used).

Nitrogen is an abundant element in our atmosphere and when converted to a solid form is readily used by plants. Coffee grounds have a carbon to nitrogen ratio of 20 – 24:1, which is about the same as grass clippings.

The relatively high nitrogen content makes coffee grounds a ‘green’ addition to the compost bin, and a great offset against high carbon ‘brown’ additions such as leaves (60:1), straw (75:1), and cardboard (350:1).

Much of the nitrogen within coffee grounds is of a type that must first break down in the soil before the plants are able to make use of it, which makes the grounds just like a slow release fertilizer when put directly into the soil, providing ongoing nitrogen input into the garden.

Used coffee grounds are slightly acidic, with a range typically between 6.9pH and 6.2pH. It would be higher except that most of the acid within the beans is extracted during brewing.

For many vegetable and ornamental plants, the desirable pH range is 6.9 to 5.8. A pH level of 7.0 is considered neutral, and from there it is increasing in alkalinity.

Coffee grounds contain phosphorus and potassium (which with Nitrogen completes the macronutrients required for all plant growth), and includes magnesium (a secondary nutrient) and copper (a micronutrient), in sufficient quantities that you will not need to get these from other sources.

Impact on animal life – to deter or attract

In learning about organic gardening, I have come across a large number of traditional methods for controlling garden pests. If for example, I make a solution of soap, garlic, chilli, and water to deter aphids, then that’s one less bottle of chemical poison in the environment. Coffee grounds have long been used in gardens because of their impact in controlling pests.

When applied to the soil, coffee grounds will deter snails and slugs, which are affected by even trace elements of caffeine, and I have heard but not confirmed that they don’t like travelling over the course grounds. I have seen a dramatic reduction in snails and slugs since using coffee grounds in the soil. If you have them in plague proportions and the above is not effective, you might want to try fresh coffee grounds, before the caffeine has been extracted.

I have seen a similar reduction with ants, and although not as troublesome as snails and slugs, they can prove damaging to seeds and seedlings when in large numbers. Having a layer of coffee grounds acts as a barrier that ants will not readily cross, and while the effects are not as long lasting as the chemical ant barriers, they do not contain all the poisons either, and it is no trouble putting down more grounds once the first lot has broken down.

Although I have never had a problem with cats in the garden, there is some evidence to suggest that they do not like the smell of coffee grounds and will prefer to keep away from it.

One creature that does love coffee grounds is perhaps the most beneficial to the garden, these being earthworms. From my own experience and from many others, they love the stuff, are attracted to it, and your soil will be healthier as a result. This applies just as much to the worm farm as it does to applying it directly into the garden. Worms of all types will be more productive as a result.

Preparing your own soil

A gardener once told me that he didn’t feed plants, he fed the soil which feeds the plants.

As long as you have good quality soil, you will have more healthy and productive plants. In addition to the result it brings to the garden, there is a great deal of satisfaction in returning a good percentage of our ‘garbage’ back into the earth.

When added to your compost bin or heap, coffee grounds will raise those internal temperatures, which speeds up decomposition, and the end result will be beautiful, black, rich compost. The most common ingredients I use for compost now are kitchen scraps (no meat or pineapple and limited citrus), shredded cardboard and paper, coffee grounds, leaves and twigs, and any edible plants no longer being productive.

I would recommend limiting the use of coffee grounds in the worm farm or compost bin to about 25% of the total volume. The reason being is that you need a balance of ingredients with most recipes, and this is no different.

If you would rather use liquid fertilisers, add half a kilo of coffee grounds into a bucket with 10 litres or so of water, let the mixture warm up to ambient temperature, swish it all around and then apply directly onto your plants.

I have heard that this works particularly well with roses, camellias, azaleas, gardenias, hydrangeas, rhododendrons, and blueberries.

There is one final benefit; your garden will carry the aroma of freshly prepared coffee for sometime after being applied!

Ground to Ground

If you are around Centre Rd Bentleigh in Victoria, a cafe by the name of Bent Espresso has a large bin of coffee grounds behind the counter. I normally take the whole lot home, and would be thrilled for you to take as much of it as you can.

You may also notice that they have a logo stuck onto their espresso machine with the title ‘Ground for Ground’.  The logo is included in this article and you are welcome to make a copy and hand out to as many cafes as are interested. The intention is to make it easier to ask (I know from experience it can difficult asking for something they only ever throw in with the rest of the rubbish), and easier for them to give. Having the logo displayed means they understand, and want to make a difference also.

If you are in Australia and need help getting some stickers, you can email me and I’ll post some out to you (shanegenziuk@gmail.com).

If you are already collecting coffee grounds, hopefully something has been covered here that is new to you, and for those of you that are yet to try it, hopefully this is an opportunity you can share with us, to make a tangible difference to our environment, and our gardens.

Cheers – Shane Genziuk

From Linda Rogan of FOWSP (Friends of Warrandyte State Park):

Hi Mick,
Hope all is going well out your way.  The cool change has certainly been
welcomed.

I would like to utilize Warrandyte Chat to let people beyond FOWSP know
about a Blue Banded Bee project we are starting at the nursery.  We are
making nesting blocks for these bees that dig holes in the ground in order
to nest.  It will be very helpful if we can acquire some material from
current Blue Banded Bees nests to rub on the bricks and attract the bees
with the smell of others.  They are nearby as they do visit many of the
flowers in the nursery. I have been told that it is not uncommon for these
bees to next in the walls of mud brick houses.  My plea is that anyone who
is aware of Blue Banded Bees or other native bees on their porperty, contact
me if they are happy for me to come and take a little of the material (just
the loose diggings and frass) for our project.  I have attached a photo of
the bee so people will know what they are looking for.

Thanks,
Linda