coffee as soil amendment

username_5(banned for no reason)November 2, 2005

Why is it that some go bannanas over coffee grounds as a soil amendment?

Am I missing something?

I mean sure, they make a fine amendment and using them for the soil is preferable to using them in a landfill, but it seems some actually take the trouble to go to starbucks or elsewhere to get a free, small bag of them.


Is there any way in which coffee grounds offer more benefit to anything than say grass, leaves, grains purchased in bulk, manures etc. In other words given the ease of obtaining large quantities of many other excellent soil amendments, why are some going through the trouble of aquiring coffee grounds in rather small quantities?

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They are extremely appealing to red wigglers, so if you are into vermiculture, that's one reason. They are also a great addition to compost and composters are an eager, aggressive bunch and seemingly will go to great lengths to acquire freebies for their compost pile. They also make a very nice, free, organic amendment for acid loving plants. I don't go out of my way to obtain them, but if I am visiting my local Starbucks and they have a few bags available, one or more will go home with me.

    Bookmark   November 2, 2005 at 10:13PM
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My nearest $bux (and there arent any indie coffee houses on my end of the boonies) happens to not bag their grounds. A guy was getting them regularly for his garden. Seems like hes quit for the season.

Ive asked a few times, and one of the employees is a bit more entertained by my crazy than the other usual guy, but Adam (finally learned his name) came to the door with the bagged grounds as I was getting ready to leave tonight (it was nice enough to sit outside)

So yeah, Adam has a special place in my heart! Ive already promised the guys and gals some tomaters next summer! I get a good 10+ lbs most times I go.

I am a coffee shop kinda gal, and theres not much else going on in the evenings on my end of town (ok, sportsbars) I also like free stuff that stays out of the waste stream.

    Bookmark   November 3, 2005 at 1:02AM
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People who do see spectacular results by adding coffee grounds to their soil probably do not have a good healthy soil and any addition of organic matter helps. Since the nearest Starbucks, or any other coffee shop is 30 miles away and not on my normal travel route its not someplace I would go normally and to expensive to make special trips. Compost and shredded leaf mulches work quite well in my garden and when I do put some of my coffee grounds down I see little reaction from the soil dwellers. However there was a vast improvment in soil acitvity at church when I put the coffee grounds in a flower bed there, a flower bed that had no organic matter in it when I started.

    Bookmark   November 3, 2005 at 7:11AM
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I use them on my acid loving shrubs for the acidifying effects and the worms. It does take a lot to "blue up" a Nikko Blue hydrangea though.

    Bookmark   November 3, 2005 at 7:30AM
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ive read theyre nearly neutral, most of the acid comes out in the coffee- Ill have to get out my happy little pH paper and take a look....

    Bookmark   November 3, 2005 at 8:56AM
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captaincompostal(z7 AL Bham)

During this season on my farm, I use lots of bags of strong smelling coffee grounds from local coffee shops, as a pest control and soil amendment.

Slugs and snails and some worm pests are repelled or harmed by coffee grounds.

    Bookmark   November 3, 2005 at 9:01AM
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username_5(banned for no reason)

good info folks, thanks.

    Bookmark   November 3, 2005 at 10:34AM
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My reason for grabbing coffee grounds is they guarantee the compost will be HOT!

    Bookmark   November 3, 2005 at 11:36AM
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rhizo_1 (North AL) zone 7

garnetmoth, you read right.....used coffee grounds are practically neutral in their pH reaction. That's been a difficult myth to bust!

    Bookmark   November 3, 2005 at 12:57PM
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U5, It's also one of the most convenient sources of nitrogen for me. I have very few lawn clippings because of droughts in our area. I get them in reasonably large hauls-probably 1/3 of a large garbage bag-from starbucks when I go to the movies. I do not always get coffee, sometimes I do, depends on if I want coffee. I ask them for the full bag so they don't have to re-bag it into the special 'grounds for the garden' bag which saves them time and I get more so it's win win.

    Bookmark   November 3, 2005 at 1:20PM
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I may not be as clever as I like to hope, but the espresso pies made me get to wondering today, Id like to offically coin the phrase "Yuppie Manure" for used coffee grounds! I am a coffee drinker, and have been since like 8 yrs old (Imagine, i might have hit 6' without all that caffiene!)

I mean it in all sillyness. Regular joes like joe too. its just really funny to me.

I just got finished cooking a mostly manure pile, and I know it has its benefits- (Neighbors are really sweet and raise donkeys) but the stuff was DRY, and I really had to water to ever get it to cook. The coffee grounds come wet, so I think they start faster. I can feel the heat rising off the pile toady, didnt dig all the way in.

    Bookmark   November 3, 2005 at 4:26PM
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Do you have any actual anylsis of the pH of them?

    Bookmark   November 3, 2005 at 8:48PM
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username_5(banned for no reason)

Just for giggles and because I wanted to put the claim to the test I just tested my pot of coffee and the left over grounds using ph paper that indicates in the 4.5-7.5 range in 1/2 increments.

The coffee was 5.0 and the grounds between 6.0 and 6.5

I would imagine there is some variability in the ph of the grounds based upon how much water is flushed through them. In this house we like our coffee strong and black so we use a lot of grounds. If we used less grounds it might be closer to neutral with the same amount of water flushing through them.

Also i didn't have distilled water on hand to run the test on the grounds so I had to moisten them with stored rain water (ph tested @ 5.0) which is acidic by nature. However, it was the least buffered water source I have on hand so it is what I used. It is possible the ph of the grounds is actually slightly higher. I won't know until I have some distilled water to test with.

Of course the water used to brew the coffee was tap water which is well buffered and on the mildly alkaline side. I don't know how that affected the ph of the coffee and won't know unless I brew a pot with distilled water.

Regardless, it is definitely true that the coffee itself is more acidic than the grounds.

Due to the water sources used it means if anything the coffee could be more acidic than 5.0 and the grounds less acidic than the 6-6.5

    Bookmark   November 3, 2005 at 10:05PM
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Around this time last year, I began reading about used coffee grounds on this forum and at the Soil and Compost Forum.

In 2002 I began gardening on a new property where the soil was poor - one side sand, another area clay, ash pockets from a forest fire years ago, not to mention the granite boulders. For two years I gardened in this soil from hell, not being able to afford loads of amendments to change it's composition. Things grew, but not like at the 'old' place.

Last fall, I approached a gas station which serves a lot of coffee about getting their UCGs. It was on my way home from work, so that was good. I won't spend $$ and go out of my way. Deal was I would give them a clean bucket every night, and take the UCGs out.

Started building a compost pile with UCGs a year ago. Leaves were available freely too - and lots of them - and seaweed is a stones throw at the neighbours' beaches, banana peels from the bakery on the way home, pumkins at this time of year, etc.

Throughout the winter, the pile was warm and sometimes hot. The snow always melted on the very top and surrounding area, which kept the pile moist.

By the spring, I had a nice withrow pile surrounding a maple. It was 4 feet high and 3 feet wide and quite long. I began using it in the gardens.

First thing is I HAD WORMS!!!! I had never seen worms here in 2 years.
Then I saw a lot less slugs!! I have a nice hosta garden, and the slugs weren't there... YES! Oh, and the deer were staying away too - could it be they don't like coffee either? And the ants in the gardens up against the house were no more. Others have noticed that ants appear to 'disappear' when you compost/amend the soil with UCGs.
Growth was amazing and full and strong and lush and... well, you get the point.
By the end of June, the winter pile had disappeared, but we were already using the spring piles. The UCGs make the compost heat-up really nice, and the spring piles were ready to go.

I now bring home about 300 lbs of wet UCGs a week. We have only 3/4 acre, but there's still a lot more amending to be done. Right now we have 4 piles one the go, and I will start the winter pile this month.

It smells nice.
It heats the pile.
It attracts worms.
It repels slugs.
It is a good nitrogen scource.
And best of all, it feeds the soil which feeds the plants!

    Bookmark   November 4, 2005 at 7:39PM
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buffburd(z5 NY)

username_5, seems like you could just use regular tapwater for your Ph tests and call it good, since the coffee shops aren't likely to be using distilled water in their machines. And as someone mentioned, the grounds come wet.

    Bookmark   November 4, 2005 at 8:00PM
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"Smells good" is an important consideration. At my last house I used mostly coffee grounds, eucalyptus leaves, and seaweed in my compost pile. When it was steaming it smelled like ocean, coffee, and eucalyptus although by the time it was done only the eucalyptus scent remained. Mmmm.

    Bookmark   November 5, 2005 at 5:04PM
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reptilegrrl(z9 Houston)

I would use them in a compost heap but I would not add them "straight" to my gardens. I was advised to do that several years ago and my plants did NOT benefit from it.

    Bookmark   November 6, 2005 at 2:43AM
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vstech(z7 Charlotte)

well last month I started picking up a bag of UCG's each day from two diff places. well three at first, but one of them didn't like doing it, and the manager complained and made me stop coming. (can I say D'in doughnuts?) anyway the other two places are still giving me 5-10 gallon and sometimes 30 or more gallon bags of the stuff each day, and I am using it with my TONS of leaves and soon I will have very happy compost for my CLAY soil. I am also putting a thin layer on top of newspaper covering it with leaves and sprinkling that with more grounds. so far so good. we will see this spring what good it does. I haven't seen any slug damage since I started this practice. and that alone is worth the work to haul all this coffie!

    Bookmark   November 8, 2005 at 9:01PM
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Karchita(WA Z8)

This myth that coffee grounds are acidic and should only be used for acid-loving plants is unbelievably persistant. To clarify, coffee is acidic; used coffee grounds are neutral.

The FAQs for the Soil & Compost forum says UCG are neutral. The grounds from espresso places are quite dry. The bags that Starbucks uses state that the pH is 6.9. I see no reason to question that, but other, wetter grounds may be a little lower in pH because less acid is removed by other brewing methods.

As for the original question of what is the appeal, I think mainly it is that they are free, especially since other organic amendments can be very expensive. For many people it is more convenient to get them at the closest coffee shop than to buy something at the garden center. And UCG are really concentrated, so a little goes a long way.

For me, they have worked best as a top dressing if you don't put too many on at once, but success may depend a lot on climate, too. My lawns really love it, as do my hostas. I also use a lot in composting, especially this time of year when I have lots of browns and few greens.

    Bookmark   November 9, 2005 at 3:12AM
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Well I guess my follow up question is " if they have a nuetral pH when dry, but lower when wet/liquid, wouldn't they be wet when they are in the soil or rained on?"

    Bookmark   November 9, 2005 at 4:39PM
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username_5(banned for no reason)

The ph isn't affected by whether or not they are wet. From what I can tell the acidity leeches out of them during the brewing process. The more water that passes over them, the closer to neutral they become.

    Bookmark   November 9, 2005 at 4:51PM
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Karchita(WA Z8)

Right, sorry if I wasn't clear. I meant that the pH depends on the brewing method. If it was espresso, the steam leaves the grounds dry, but the acidity is removed and ends up in the coffee. Drip brewing leaves them wet and slightly more acidic and the coffee is weaker than espresso. Either way, they would still be neutral or nearly neutral in your garden, whether they get rained on or not.

    Bookmark   November 10, 2005 at 2:05AM
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Large amounts of UCG added to the soil are not a good idea. It depends on what plant you are growing. It would be much better to create a compost pile with them. I had some plants die right away from adding coffee straight to the soil. But, people are always looking for shortcuts and coffee grounds are free so people do add a lot of them to the soil hoping for a quick fix, but it takes a few years of soil improvement to see great results. Cala lilies like coffee grounds, but never add a huge amount, unless you let it wait for a few months to cure, before planting.

    Bookmark   July 30, 2006 at 11:10AM
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I bury wet coffee grounds all around my bananas and elephant ears. I also spread starbucks dry coffee grounds all over my lawn and flower beds. All are doing great with no damage anywhere. If you spread them too thick in one place and they dry they will repel water. That is the only way I have ever heard of them doing damage. I add about 5 gallons per banana and elephant ear plant every two weeks, and they are gone when I add the next batch.


    Bookmark   July 30, 2006 at 10:14PM
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I have used straight coffee from the can (not brewed) in the tomato holes for the past two years. My tomato production has increased to what I would guess is doubled over the past two years. Cause and effect? dunno, but I see no evidence that it has caused any adverse reactions.
Mrs H

    Bookmark   August 2, 2006 at 3:58PM
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Dear All,

After reading this blog I still have a few questions about coffee. I am the holder of a 5lb bag of French roasted coffee beans that have become too old to use for coffee. I've been holding on to them because I can't stand the idea of wasting them. Again, they are whole beans. I am wondering if sprinkling them around my Mountain Laurels and Rhododendrons will help them or hurt them? I wonder if sprinkling them under my hostas will ward off the slug attack also. Can anyone suggest?

Thanks, madamebutterfly

    Bookmark   June 19, 2009 at 10:59AM
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Madame -
The worst that can happen is that the beans decay and increase the organic content of the soil.

    Bookmark   June 19, 2009 at 1:28PM
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tapla (mid-MI z5b-6a)

Actually, I would brew them first & then add them to the soil.

You've come a long way since posting this way back when, ehh, D? ;o)


    Bookmark   June 19, 2009 at 4:17PM
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"Why is it that some go bannanas over coffee grounds as a soil amendment?.....some actually take the trouble to go to starbucks or elsewhere to get a free, small bag of them "

1) It is free
2) It is HUGE not a small bag
3) The (soil like) texture of UCG is perfect
4) Seems to be deterring deers, slugs
5) Smells divine!

    Bookmark   June 2, 2011 at 2:34PM
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I am an avid gardener , and have with in the last few years added a raised vegetable garden amidst the myriad of other raised flower beds that i have. I have only recently come across using UCG's for soil amendment. I can boast of naturally rich nutrient rich soil already, due to the forrest behind my house with the various deciduous trees. however, i believe in repurposing stuff and reducing the carbon footprint, so i have started recycling my UCG's into my compost along with banana peels. Roses love the banana peels (burried around roots) much safer for the plants than that "Miricale G" stuff ;) . but i am also deligted to know that the vermiculture love the coffee grounds,as they are a good source to airate the soil. How much is too much UCG? i have 7 raised 4x8 foot beds. (Depth of bed is approximately 1' deep. i also plan to put aged cow manure along with it over the winter. ( i live in Northeast). any one have an idea how much i could safely add in mulch pile to increase within safe quantities? i rotate my crops in each bed yearly. but want to do the best i can to maintain a proper balance within each bed consistantly.

Best regards and happy gardening!

    Bookmark   September 23, 2013 at 10:41AM
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I don't know how much is too much. I had awful clay soil. Last year we Put 12" tall borders on top of the clay (2 10x6 beds) and started filling them with whatever I could find. Mostly compost and wood chips. This year I have added a ton of coffee grounds around the plants on top of the soil, never mixed in except by worms. My neighbor works at Starbucks and brings me about 50# a week of grounds. They all go on the garden beds.

My neighbor used garden soil to fill her beds. My tomatoes and peppers have outproduced hers. She uses Miracle Grow, I've used no fertilizer. Hers have suffered insects, blossom end rot. I have had no issues. I don't know if it is all due to the grounds or the compost base but IMO you will never have too many grounds. I wouldn't mix them with the soil just as I wouldn't mix in unfinished compost but as a topdressing they have definate value.

    Bookmark   October 1, 2013 at 8:06AM
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