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Jamie garden
Sal garden worm 9
Sal and worms both lovin' the coffee

Coffee and gardens

The best way to use coffee in the garden? After days – weeks, even – of research, here is my definitive Number 1! Find a warm, sunny day. Put a garden table and a couple of chairs in the sun or shade – whichever you prefer. Brew up one of your favourite Coffee Buddies™. Sit and enjoy, look at the birds, bees and flowers. Ahhhh!!

Now about what you can do with coffee grounds in the garden…

First, make sure your used grounds are mixed with plenty of water. Walk out the back (or front) door and fling the slurry in the general direction of the nearest grass, plant or tree. NOT RECOMMENDED!

But seriously, folks, let’s start with what coffee grounds contain.

There’s caffeine, of course, which tends to inhibit plant growth – so it may help kill weeds, but it may also kill your plants, especially seedlings! Caffeine may help deter slugs and snails, which aren’t keen on it (or the gritty texture of coffee grounds) but opinion on whether this really works is divided. Seems that if there are lots of the slitherers, coffee won’t be your salvation! And the caffeine content of used grounds may have fallen quite a lot – but opinion is divided on this one too.

Then there’s acid. Fresh grounds are acidic – but why in the world would you want to waste your fantastic Get in the Mood® coffee on feeding your plants? Used grounds are probably pH neutral.

And then there’s nitrogen – quite a lot of it, plus a bit of potassium and phosphorus.

But what’s the best way to use it?

Illustrat sal garden
Sal's illustration of herself at her allotment

You can put it on your garden as a fertiliser or mulch, but don’t heap it too thickly because it clumps and prevents water from seeping through. Too much in one spot may also concentrate caffeine in the soil and prevent plants from surviving there next year! Rake it fairly thinly into the top of your soil, and don’t put it too near delicate plants. Or mix it with other compost materials.

And forget using it on your acid-loving hydrangeas and azaleas – because the acid went into your drink! (Tomatoes, though acid-liking, definitely don’t respond to coffee!)

Overall, best to add it to your compost heap. It’s regarded as ‘green’ compost, so it needs to be balanced with ‘brown’ compost such as leaves, woody material or newspaper. Our ambassador Sal has an amazing allotment and she's an avid fan of re-purposing our coffee just like this.

Or you can put it in your worm farm – again, as long as you mix it with plenty of other food and paper or cardboard. I suppose the graininess of the coffee is good for the worms, which need some gritty food for their digestive tract to function properly. It certainly works for my worm farm!

Finally, use it as a cat deterrent! Apparently they don’t like the smell of coffee. On the other hand, dogs that eat anything and everything in the garden (border collies come to mind!) will get an upset stomach from eating the grounds, so beware!

Now relax and have another coffee!



Sal garden 3
The allotment that really does give back!