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Can coffee grounds be converted into a water soluble fertilizer through active aeration?

 
Saybian Morgan
gardener
Posts: 582
Location: Lower Mainland British Columbia Canada Zone 8a/ Manchester Jamaica
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So I'm looking at this weeks coffee ground haul from work and I see 5 gallons, which is the exact amount of worm castings or compost I use in my tea brewer.
I've already broadcast it everywhere and it's boring in it's availability to plants, as I mainly feed it to the mulch to bring the worms higher. If I "worked it into the soil" as all the websites say, I wouldn't have any skin on my hands left by the time I was done.
What I don't know is how the nutrients remnant in the almost carbon like structure are stored or released, so I fail to be able to articulate the reason why I should be able to displace the nutrients into the water.
I know in my setup bacteria is dislodged by aerated force against the dome surface that clamps to the bag, but really i don't believe you can beat atomic structures apart.
Plants work with a myriad of collaborators with innate abilities of there own to augment elements and pass them downstream.

What seems to contradict that clear rational is the particle size and clear mutations of the base bean, from roast, to grind, to brew, to sit in a bag hot and start to go fungi.
I get this intuition it's already carrying the self digestive elements within it's carbon architecture to be separable like the carbon found attached to the nutrients and bacteria in compost.
It's ability to provide the ignition in composting verifies it's catalytic content, which is what where after in many ways from composting and castings.
I feel like there's a third stage before brewing, and I don't know why I feel like comfrey, yarrow, lucerne, kelp, lacto bacillus and molasses are involved.
Its borderline anaerobic if it wasn't form the crumb structure of the coffee mixed with those wet elements, the maximum I want it to go is 3 days in a garbage bag.
Like when you forget the vegetable scraps behind the door and they are steamy when you find them. Active microbe material basically, that will multiply in the aerated water and break down the elements in the grounds to soluble levels all the way through the process.


 
chrissy bauman
Posts: 131
Location: Sunset Zone 27, Florida
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your question was highly detailed and well written

i believe the reason that most of the websites you have found about reusing coffee grounds in the garden - mixing the grounds with other plant tissues is to counteract the the coffee grounds natural acidity. if you are able to truly ferment the grounds, probably a lot of that acidity would break down to a less detrimental form.

if you were to just spread the coffee grounds thinly over a large area of soil, you probably won't have any trouble with the acidity and it will, overall, benefit your plants.

most conventional wisdom would say to compost the grounds with green plant matter, then when it's broken down to use that in your garden. where i live, during our rainy season i put all our kitchen scraps including uncomposted coffee grounds into the garden or even right into the lawn. it naturally breaks down quickly. during the dry season i use the compost pile. but then i'm only one small family, not gallons of coffee grounds from a workplace. i bet blueberries would love some coffee compost or tea.
 
Nicole Castle
Posts: 151
Location: Madison, AL
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chrissy bauman wrote:i believe the reason that most of the websites you have found about reusing coffee grounds in the garden - mixing the grounds with other plant tissues is to counteract the the coffee grounds natural acidity. if you are able to truly ferment the grounds, probably a lot of that acidity would break down to a less detrimental form.


I know there are many web sites which continue to perpetuate this myth, but coffee is acidic; coffee grounds are not necessarily.

Unfortunately this article does not cite sources of the research she reviewed, but it may give the OP some ideas and places to look when looking for more places and ways to use their grounds.
http://www.puyallup.wsu.edu/~linda%20chalker-scott/Horticultural%20Myths_files/Myths/Coffee%20grounds.pdf

 
chrissy bauman
Posts: 131
Location: Sunset Zone 27, Florida
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simple chemistry tells us that if you take a substance, say used coffee grounds, and add water, and the solution is acidic, then the substance is acidic. the nice article above speaks of the pH after composting. i'm not completely sure the writer understands the pH scale, because she said she added grounds and the pH went up, then came back down. so she said she added grounds and the mixture went more basic and then came back to acidic, which is opposite of what would actually happen. so it is unclear if anything she wrote can be trusted, particularly since she didn't actually have research to cite from.
she does make a great point that if used as a direct mulch it can cause compaction, and i can say that i have seen this in my garden. it's like using cat litter or sawdust as a direct mulch, not the most optimal situation for most people, but it is do-able.

She also made the point that it can be applied directly to plants as is, as saybian wanted to do with the water and active aeration. I wouldn't even take the time and energy to actively aerate it, if you had the equipment to do so. just mix with a ton of water and get it onto the soil thinly. but you know it would be completely safe if it was fermented.
 
Rich Pasto
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I tried using coffee grounds to acidify my soil for over a year. Because 'conventional wisdom' said they are acidic. Not so much. peat moss actually tests as acidic - below 6 - grounds pretty close to neutral with my store bought kits.

Then my nitrogen levels tested off the charts, with the PK components still deficient. That area is basically an in ground compost pit now to bring the nitrogen to normal levels and fortify the PK. Best way to use coffee grounds is to use them as the nitrogen source for a compost pile. use that amazing compost to feed your plants. Spreading it in your mulch is doing the same thing, just not in a pile. Your mulch is all carbon, it needs N to compost.
 
Saybian Morgan
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Location: Lower Mainland British Columbia Canada Zone 8a/ Manchester Jamaica
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That article hit the nail on the head, the bacteria that develop on decomposing grounds are extra goodies I can multiply in my tea. I want more than just the npk of things, npk alone is not what I call fertilizer. Those microbes that turn unavailable material into available material is how I get fertilizer out of what's already innate within my soil structure. There's plenty of food out there it's just locked up in one form or another, I don't even want to go into the medicinal aspects of what's being applied to plants or I will be avalanched by evidence I should get off this computer and go jam some comfrey n such in the garbage bag n start cooking.
Yep I'm feeling good to go now, I recommend us all checking out the article as it may unlock another dimension of interest and evidence that in our communities there's an abundant return of surplus that we must prevent from becoming a pollutant. As permies we love free stuff, and turning garbage into gold is our Midas touch.
 
John Polk
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Location: Currently in Lake Stevens, WA. Home in Spokane
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Coffee grounds are acidic until you brew them. Once brewed, most of the acid is in the cup of coffee, not the spent grounds. The tests that I have seen on used coffee grounds have pH's between 6.7 and 7.0

They should not be used on blueberries, or any 'acid loving' plant...they will sweeten most soils.

(And coffee is way too expensive to use unbrewed grounds for agriculture.)

 
Nicole Castle
Posts: 151
Location: Madison, AL
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chrissy bauman wrote:simple chemistry tells us that if you take a substance, say used coffee grounds, and add water, and the solution is acidic, then the substance is acidic.


In the case of coffee, the acidic compounds are water soluble -- so the acidity leaches into the coffee (and out of the grounds) during the brewing process.

i'm not completely sure the writer understands the pH scale, because she said she added grounds and the pH went up, then came back down. so she said she added grounds and the mixture went more basic and then came back to acidic, which is opposite of what would actually happen. so it is unclear if anything she wrote can be trusted, particularly since she didn't actually have research to cite from.


This is exactly the reaction you'd expect from material with a high buffer capacity. Buffers resist change in either direction on the pH scale as as a result the final solution will be to move toward a neutral pH. Coffee grounds have a high buffering capacity, so they help neutralize soil.

For those interested in further reading, I checked Dr. Chalker-Scott's web site directly and found her list of sources for the coffee article:
http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/Literature%20files/Coffee%20ground%20references.html
 
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