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From Cup to Compost

It is pretty hard to believe that spring is past and summer is here! I love this time of year. Gardens are buzzing with life. I want to take this time to discuss using coffee grounds in compost. Coffee grounds are extremely rich in nitrogen, and can be a great, organic way to boost your garden growth. They have to be used correctly, though.  It is not a simple matter of dropping them on your plants and walking away.

Building your compost heap

Worm Castings
Worms decomposing organic material at Cocafelol in Honduras.

First, let’s talk about compost.  Many people like to compost all plant waste that comes from their kitchens. I love doing this too, but I have heard recently on my favorite podcast, You bet your garden, that it is actually best to decompose most kitchen scraps in worm houses rather than your traditional compost heap. Compost piles outside in nature will take a very long time to decompose your carrot peels, avocado skins, and other veggie scraps. There is one thing you all have in your kitchens that an outdoor compost heap will LOVE. That is coffee grounds. Your best bet for fabulous compost made with coffee grounds is to collect your leaves in the fall, shred them, mix them with your grounds, and use that as your compost pile. You will need about five times more leaves than coffee. The carbon from the leaves will decompose with the nitrogen from the coffee, and you will end up with a balanced additive for your gardens.  

Coffee grounds look kind of like dirt. I think that sometimes tempts people to skip the decomposition process. That process is extremely important. Before decomposing, coffee grounds are so nitrogen rich, that heavy doses can “burn” the roots of your plants. Too much of a good thing is a bad things in this scenario. Also, nitrogen stimulates green growth and can inhibit flowering and fruiting in plants. If all you add is nitrogen, you may not end up with as many tomatoes as you were hoping for this year.

Composting balances acidity of grounds

Coffee grounds are acidic. Some NH plants, like blueberries, love acidic soils. I may consider adding a tiny

coffee compost gardening
We use our coffee compost on the herbs and veggies we grow at the cafe. Was there arugula on your breakfast sandwich? It may have been grown with coffee compost.

amount of grounds to my blueberry soil when the plants are done flowering, but it would be purely experimental. In general, it is not a good idea to acidify the soil in your flower and vegetable gardens to that degree. This being said, last year before I did my research, I added grounds directly to my garden and it was fine. It didn’t kill anything. I think it may have become more of a problem over time if I had continued at that rate. When you compost your coffee grounds, the process will balance out the pH, so your final product will not be as acidic.

Need some grounds?  We’ve got plenty.

We produce mounds of grounds at A&E ;-)! If you would like to take some home just bring in a 5 gallon bucket with your name and phone number and we will easily fill it for you in a day. All it takes is patience. Heap those fall leaves with coffee grounds in October. Take coffee grounds home and add them to your existing compost heaps now. They are fabulous for compost! They just need to go through that whole process before being used.

coffee compost
Coffee cherry heap at Cocafelol in Honduras 2016.

We compost all of our grounds in a giant heap behind the plaza at A&E.  This reminds me of the giant heaps of coffee cherries the coffee farmers compost during the depulping process in coffee production.  We purchase organic beans that are produced with care and nature in mind.  I think it is really cool when we can continue that cycle of caring for the earth on our consumer end.  The beans that were grown in far away lands can help nourish our flowers and veggies in the granite state.