Coffee Compost for Containers
Now with these thoughts in mind, can you believe this statistic I came across? ‘They’ say, and it is generally acknowledged, that 500 billion cups of coffee are consumed globally each year. How they work that one out is a mystery to me – but we all know that coffee is a mainstay at the start of the day for many people ... and if we consider using the spent coffee grounds from what we've brewed in the garden – that is an awful lot of fertiliser!
Coffee in the garden? In your containers? Well yes actually – there are some very good uses that we explore below. Even though there is a lot of research on the subject that is on-going (some of the results have been conflicting, others incomplete, evidence is still being reviewed and discussed) it is nevertheless a very popular gardening practice. Perhaps it is a case of bumblebee logic? You know, where the bumble bee can't fly because of its body design and weight ... but the bumblebee doesn't know this so it flies anyway.
I have been using coffee grounds for a long time and have yet to lose anything in my containers or my garden (except for chasing away ants and snails!) I feed my soil regularly but do not add too much ever, maybe that is why I feel so comfortable in spite of some of the uncertainty a person can read about. I say it is a matter of personal choice – as is the case with many gardening tips and practices.
For me, coffee gardening is easy to implement; good for the soil and good for plants. So, let’s see.
Now we‘re not considering instant coffee here, (I am not even sure if you would use it at all) but we are considering the spent coffee grounds from fresh brewed pure coffee (no chicory mixes) most usually made in a Bodum or French Coffee Filter machine. Come to think of it, these used grounds are usually just thrown away and for the most part wasted, unless of course you know better.
I learnt about the uses of coffee grounds in the garden at one of my Garden Circle meetings some time ago and have been using it since then most and more often than not. Besides my precious containers, I've a very large garden to care for so I rely on neighbours who recycle their grounds my way, as well as two very busy Starbucks-style restaurants from whom I collect fairly regularly. I cover all my garden bases around every two to three months and also shred the unbleached coffee filters.
Note though, that if you are not a coffee drinker and can’t find a source of used grounds, do not be tempted to use 'un-coffeed' coffee beans ... spent, the grounds are not so acid and as they decompose in the soil, their PH neutralises further so they will not upset the PH levels of the soil. That having been said, and even though there is an acidic aspect to spent coffee grounds, do not think that their addition to your soil can take the place of acidic composts – they can’t.
So how can you use coffee grounds in your garden? There are several ways and, believe it or not, there are several other uses for grounds that are not garden related (I have a brief summary of these at the end of the article just for interest). Anyway, it is a good start to and an organic approach to your soil and plants.
Preparing your coffee grounds for garden use:
Once you have collected enough coffee grounds, you can begin to make them work for your containers. How much is enough? Can’t say – it obviously depends on how many containers you have or how big your garden space is. Go for a ‘less is more’ approach until you get used to using it.
Use dry grounds as they spread more thinly and more easily. To dry them I spread them out on trays or any flat surface and let them dry out, tossing them now and again. Of course sunny days are best, but drying them inside the kitchen is fine too. It usually takes around two to three days to dry completely, but of course it depends on how much you have. You can use them wet, no problem there at all – just be careful to spread the grounds thinly. You can also freeze your spent coffee grounds for later use if you have too much or once dried, you can keep them in an airtight container and label them clearly as used coffee grounds. If they happen to go mouldy, you can still use them in the garden, but my choice is to throw them away and be more careful with my drying and storing in future. They will keep a long time, but make sure you start off with a fresh product – collect more often and use quickly.
Don’t forget - use your gardening journal to note down your coffee gardening actions – how much, where, when, results and so on.
The nutrients found in coffee grounds that are so beneficial to plants and soil and all include nitrogen, carbon, calcium, phosphorus, magnesium and trace amounts of other important minerals. Imagine that all free and we usually throw it away. Still it reminds me of that saying – ‘Before you know how to ride a bicycle, you didn’t know how to ride a bicycle.’ Gardening, like life is just so – until you know how to do something you don’t! Anyway – using spent coffee grounds you can:
• Add them to your compost heap if you have one, and keep it small. Do not add more than 20 to 25% of coffee to your other compost ingredients. The coffee will speed up decomposition.
• Use them as a soil conditioner, they improve soil tilth; enhance plant growth because grounds are a free source of nitrogen amongst other precious trace elements.
• Add them to your worm bin. I read that they are a delicacy for earthworms (my favourites!) and better than ice-cream! They feed off them, but the grounds also supply a source of roughage which aids in the breakdown of food, soil aeration, microbial action and the production of the compost. Coffee grounds provide your plants with major nutrients N-P-K in a slow release form - just what the doctor ordered.
• Use them as mulch. Don’t spread it too thickly or it will go crusty and may even become mouldy. Besides, it will stop air into the soil and may be a barrier to your watering. When using it as mulch, add a pinch of lime if you like (not imperative) and spread just about a half an inch layer on top of the soil, muss it up and then cover this with bark chips.
• Use them to repel ants, slugs and snails. Luckily, containers are not badly affected by these (except some vegetable ones) and in that instance, just add a line of grounds around the periphery of the container, and the slugs should stay away.
• Use them as a liquid fertilizer, but here we are speaking of the grounds being seeped in more water, we are not speaking about left over black filter coffee. This is still acidic and often too much so for your plants.
• Many flowers love them – Roses! Tomatoes! Hydrangeas! Camellias! Gardenias! Rhododendrons! Blueberries! Cranberries! Citrus! But don’t stop here – any plant will love what it does to the soil. Have you got a lawn lurking somewhere as a backdrop to your containers? Lawns love it.
Other non-gardening uses for Coffee Grounds. In brief, I found out the following. I haven’t tried it for these purposes, but think I will as I go along, why not?
• Neutralise odours in the ‘fridge, just place a cup of grounds in the back somewhere. Replace every two months or so.
• Scour away grease and grime from pots and surfaces. Rinse well once done.
• Make a hand scrub by rubbing the grounds between your palms. This has a two-fold use. One, it will take away any rough skin and you will end up with soft hands, and two, food smells like garlic or onion and fish may be lessened if not eliminated.
• Fortify seedlings and promote germination by adding small amounts to the soil for a nutritional boost. Water them in with a spray.
• Use them as a wood stain or hide furniture scratches – depends on circumstances but it’s worth a try.
• Throw damp grounds over your fireplace ashes before cleaning the grate. They will help minimize the ash dust.
• Beauty uses include using grounds as a defoliant and/or an anti-cellulite rub.
Not bad for a ‘waste’ product that is usually thrown away unused. Repurposing coffee grounds is certainly worth your while!
Perhaps we can agree with Thomas Jefferson who apparently said “COFFEE. The favourite drink of the Civilised World." Yes – it’s very likely.
What do you want your container garden to do?
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