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Cucumbers & Coffee Chaff


A couple of weeks ago, our green-fingered roaster Sean drove the two of us out to the Alderman Moore allotment. It was a grey, still afternoon. The plots were empty and quiet, except for a black cat who picked his way silently over the vegetable patches.

We parked up next to the shuttered allotment shop. Sean explained that it covers all three of the Hotwells and District allotments. It stocks an assortment of essentials for the allotmenteers, from second hand tools to seed packets. Everything is sold on subsidy so the money can go back into the association to keep it going and make improvements.

We left the bags of chaff against the small building and labelled them, encouraging people to help themselves. Sean told me that the bags are normally gone within a few days of him putting them out. Impressed by its popularity, I wanted to know what exactly is chaff and why is it so great for the garden?

When coffee is roasted, it sheds a husk, similar to a dried skin. This is chaff, and despite having no purpose in the coffee roasting process, it has incredible properties as a byproduct. When added to your compost heap, it introduces a healthy amount of nitrogen and enriches the soil.

As Sean sprinkled a layer of chaff into his own compost, the bluish outline of the Clifton Suspension Bridge visible in the distance, he explained that chaff works particularly well as a mulching agent. He said it’s best to add a layer of chaff onto your food waste then more compost on top of the chaff. You could add it straight onto the soil but it’s better not to; it’s light weight means it blows away easily and it absorbs water very quickly, which makes it incredibly slimy. It does however make great bedding in chicken coops, particularly as an alternative to sawdust. For more information, take a look at this article

Coffee grounds are also a useful addition to your soil. All the acidity in the coffee is removed after brewing, so as they decompose and provide food for microorganisms, the grounds help the pH of the soil towards neutral. They also act as a great pest repellent; snails and slugs have a strong aversion to a good brew. Like chaff, coffee grounds also help raise the nitrogen levels in the soil.

It’s great to have a renewable use for our coffee bean waste, as well as the opportunity to help out the Hotwells and District allotments in their commitment to making their green spaces as environmentally friendly as possible. There are already compost loos on each site and every structure with a roof has to have a waterbutt attached to it. They encourage people to use water from these rather than from a tap; as well as being better for the environment, it saves money!

Although there is a tentative plan to supply other allotments, our chaff isn’t reserved. If you fancy some for your plot of earth or veg patch, you are more than welcome to drop by the roastery and pick up a bag.

Using chaff or coffee grounds is a win win if you’re a coffee lover and enjoy nurturing your own greens. It’s time to get a little coffee in your garden and make it “smell like a coffee shop after a summer rain.”

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