Coffee grounds. Free to a good home.

Photo: Jenny Harlen

Photo: Jenny Harlen“Hello gardeners! Please take some coffee grinds for your garden!”

What gardener could resist that? Well, unfortunately I had to as I was just a tourist passing by. But I was seriously tempted to drag some home to the friends we were staying with.

Coffee grounds are just great in the garden. The nice thing is that they’re brown, so you can just spread them out under bushes and in garden beds. Smells nice while you’re doing it and pretty soon they just eat their way down into the soil where the nitrogen in the grounds is released to the plants nearby (with some good help of whatever microbes are in the vicinity).

The only disadvantage can be if you use a lot of coffee grounds in your veggie patch that the carrots start tasting like coffee. No, just joking. There can be a risk that heavy metals in the coffee build up in the veggie patch if you overdo it. My feeling is that it would take an awful lot of coffee to get you to that point, and the greater worry would be whether we should be running that much coffee through our bodies. However, worth checking out a bit more if you’re concerned.

The alternative is to dose up bushes, trees, flower beds, even a smallish lawn with coffee grounds — none of that is going to get into the food chain. It’s a cheap source of nitrogen and a cool thing to do, just swag home with a bag of coffee grinds when you pass your neighborhood cafe.

Unfortunately none of the cafes round us do this. I’m hoping that will change gradually, like so many recycling-related things. Common sense does seem to be kicking in all over.

A few years ago I did a deal with the local bakery/cafe to pick up their coffee grinds once a week. I kept it up for a few years until other priorities took over, hopefully they have now adopted a new coffee collector.

My original idea was to do bokashi of the grinds to increase their microbial value in the soil. Great idea, well worth doing, but for me at the time just too hard work. So what I did was just dump the buckets of coffee grinds under our multitude of bushes, one bush at a time. Sometimes the buckets were frozen because they’d been stored outside, I just dumped them under the bush as they were. Come spring the weird collection of coffee towers mushed together and I could rake them out a bit.

Given that we produce bokashi bran here at home it’s not something we have a shortage of. Each spring I’d go around with a wheelbarrow of bokashi bran and throw a handful or two under each coffee bush. The microbes could spend the summer doing their good work.

Obviously you could get the same result using bokashi juice (the runoff from a bucket with drainage tap) or using EM in activated form. Either way, pretty cost effective and hard to overdose.

In the autumn I usually pile up a lot of leaves under the bushes and rake a lot straight into garden beds. Partly because I’m lazy and it’s easy to shuffle them up into the first best spot, but mainly because with such an active soil the leaves are rapidly absorbed into the soil around the bushes. They also keep the worms warm and happy for a good while into the late autumn and that’s always a good thing.

People around here say that coffee grinds are a great way of stopping snails in their tracks. I haven’t tested it myself so can’t say for sure, but it seems reasonable. Tugging a slimy snail body over a barrier of coffee grinds is probably not the most pleasant of options for a snail. Have you tested it? (Not dragging yourself through the grinds, obviously, but spreading them in the garden.) Is it worthwhile giving it a go?

So, all up — a lot you can do with coffee grinds without it being such a chore. Great for the garden but the greater good is probably getting them out of their landfill destiny and into the food/soil loop. Well worth giving it a shot in other words.

And you can always reward yourself with a steaming hot latte the next time you’re there to pick up your grounds!


8 thoughts on “Coffee grounds. Free to a good home.

  1. If I see this happening where I live, I would happily take some and bring the cafe some tomatoes, kale, whatever is ready for harvest as a ‘thank you’ gesture. 🙂

  2. Hi good morning.
    I wonder if I did something wrong. Last year I used bokashi juice which was sometimes a little old, -sour-. I did not noticed any good progress of the earth and plants. How could this be? Thanks ans kind regrads, Bart, Amsterdam

    1. You mean the bokashi juice had been standing for a while before you used it? If it had been exposed to the air for more than a few hours it would have started oxidising. That makes the smell even worse and causes some of the nutritional energy to evaporate as gas. It could also be there’s some form of change in the chemistry which affects its fertilisation value.
      So, to get the best out of your juice, use it straight away. Otherwise drain it into a plastic PET bottle with lid, that will keep it fresher. The less air in the bottle the better, so several small bottles are often better than one big. It will usually keep ok for a few days at room temperature, if you live somewhere hot put it in the fridge.
      For long-term storage, put the PET bottles in the freezer, it’s great to have a supply in spring and summer. Plastic ice-cube bags are also a smart way of freezing the juice in portion amounts. Lots of people do this here in Sweden (where we have no use for fertilisation in the winter) and think it works really well. Most likely some of the microbe strength is lost in the freezing process but that’s not the end of the world.
      So skip the oxidised stuff and keep to the fresh! Good luck!

  3. Hi Jenny
    I’m into my second bucket now here in stockholm. I live in an apartment, and haven’t really figured out exactly how I want to use the bokashi, might be sneaking out and burying.. sort of experimenting. I have used some bokashi mixed with soil (mixed soil into the bin after the two weeks process) at the bottom of some chili plants that had some disease recently, hoping that it would combat the disease, and fertilize them. I might be imagining, but it seems the disease is in retreat. But the smell was quite strong from the bokashi, especially in the beginning. It seems like it fades with time in the pots, but still. Do you use bokashi in your pots indoors?

    I also have one big plastic bag on the balcony with leaves and worms from the forest, old potting soil and bokashi.

    Another thing: I’ve been using the liquid a lot for watering. Everybody keeps talking about how nutritious the liquid is. But I can’t find anyone who’s analyzed it. Like how much nitrogen, phosphorus, potassium and what else. Obviously it would vary depending on what you’ve put in the bin, but still… there would be some general levels. Do you know of any research? It just seems like rumors at this point. I want it to be true 🙂 And I want to know what I’m feeding the plants, and what else they will need added…

    And about putting the brans outside in the garden, or pouring EM in the garden soil etc… How can that work, since the microbes die in oxygen conditions? Would be the same with watering pots with the liquid, by the way.

    Carl Fredrik

    1. Hi Carl Fredrik!
      Good questions, great to hear you’re up and running with bokashi in Stockholm. Guerilla bokashi by the sound of it! You could always check on the Swedish Facebook group “bokashi” if there’s anyone living nearby who’d be interested in picking up your excess bokashi, someone with an allotment maybe?

      Using bokashi indoors can be a bit tricky, I think most people set up an indoor “soil factory” and make the bokashi soil first before replanting indoor plants. Technically, what you’re doing in the pots (mixing bokashi directly into the pot) will work but it often smells more than you’d like, I assume that’s because the plant is being watered quite frequently and bokashi always smells more when it’s wet.
      If you, or anyone else, want to test making an indoor soil factory it’s easy. Just take a bucket or other container and mix 50/50 fermented bokashi and potting mix. Use the kind of soil/potting mix that you’d like your plant to have, probably store-bought rather than outdoor soil. Works fine with tired potting mix from old plants, a better use of resources as you can “restore” the old potting mix. The soil factory shouldn’t be airtight (see it as a hole in the ground), but you’ll need a layer of soil on top of 5-10 cm. Put a newspaper or old towel over the bucket etc to keep it nice and moist and put it in a warm spot. In perfect conditions (like on a heated bathroom floor!) you may even get soil within a couple of weeks, often it takes a bit longer though. If speed is important, chop the food waste into small bits before it goes into the bin.

      This ready bokashi-soil will do a great job in your pot plants and tends to smell less. Dilute it as needed with more soil, often a 30% mix of bokashi in old soil potting mix is good but chillis are pretty demanding so may like it stronger.

      As to the NPK mix of the juice — can’t recall seeing any tests actually. It’s as you say — the juice from every bucket is different and impossible to measure. Although most people seem to find it works in almost all situations.
      There’s a big difference between chemical NPK fertilizer, liquid or otherwise, and bokashi juice. Chemical fertilizers dissolve quickly into the soil and if they are not taken up by the roots of the plant will be washed away. The nutrients in bokashi juice (and indeed bokashi itself) on the other hand tend to stick around in the soil. Some of the nutrients are delivered directly to plants but most are taken up into the bodies of the microorganisms themselves in a process called mineralization. These nutrients become available to plants and other micro life in the soil over a much longer period of time. So the plants can pick and choose what they need, when they need it, in a completely other way. Seems like they find most things they need in the juice.

      As to putting bokashi bran in the garden, watering with EM, etc etc, it all works. Bokashi and EM is of course an anaerobic process (and needs to be run in an airtight manner in the bucket so you don’t get rotten food) but most of the microbes can also work aerobically in the soil. Their job in the soil is not fermentation, rather it is to focus on hanging out and finding food. Beneficial microbes work in symbiosis with plants by delivering needed nutrients to the plant roots. In return for their work they get a little dose of sugar from the plant. Nice relationship, pretty much win-win! But obviously if you’re spreading bokashi bran in the garden it makes sense to do it on a wettish day and if possible scratch it down into the soil so it gets as much contact as possible.

      Hope I’ve answered everything here! Good luck with your projects!

  4. Reblogged this on urbangardeninghamburg and commented:
    Do any Hamburg cafes hand out used coffee grounds? I saw this posted on bokashiworld and asked here in a couple of cafes but they all seem to either mix the receipts in with the used grounds or they use one central bin. Any idea where might keeps their grounds separate and want to recycle them rather than just throwing them in with the normal rubbish?

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