I would encourage moderation. Research shows that the build-up of caffeine in the soil of coffee plantations eventually inhibits the growth of coffee plants. I think if you mix coffee waste with shredded leaves and grass, you could make compost. I also wonder if that wouldn't make a good mulch. If you're going to use it as mulch, I would let it sit and decompose in a pile for some time before applying it as mulch.

When I go get wood waste (mostly bark) mulch from the nursery for garden beds, the pile of mulch is usually hot and steaming. Mind you, this is 100% woody waste and it is decomposing. I have seen this freshly applied mulch stun plants, so don't underestimate the need to let it decompose a bit before using it as mulch.

I have not found much information about the waste from the coffee bean processing plants, except some concern about heavy metal contamination from some water sources. The only reference to caffeine inhibiting growth of plants is from Idaho gardener referring to some research found. If there is published research on this subject perhaps Idaho can link it for the rest of us.

"Research shows that the build-up of caffeine in the soil of coffee plantations eventually inhibits the growth of coffee plants."

Care to show the links to this research?

Caffeine is metabolized by soil fungi and bacteria - Pseudomonas putida can live on pure caffeine as its only source of energy.

Slightly off topic, but I'm curious about why a coffee plant would discard roasted but unbrewed beans or grounds in the first place.

I wonder that too.

Then if there are some clean up stuffs, how much of it can add up ?
But anyway, coffe is just acidic. The unbrewed one is more acidic. DEcaf is less acidic. Otherwise it is a good source of nitrogen.

Thanks to all for your replies.

Link to one study that cites the effect of caffeine on growth of plants; here

Are people too stupid to do their own research?

I doubt that says what you think it does.

kimmsr, here is a quote from the article;

"Caffeine has been mentioned as a potent allelopatheic compound, inhibiting selectively weed growth under coffee trees as well as being toxic to coffee roots. It is clear from laboratory studies that caffeine can cause inhibition of seed germination in different species..." (Emphasis is mine.)

What part of this is confusing to you? Too much caffeine is not only hard on other plants, it's hard on the coffee tree, too.

What's chapping my ass right now are the self-appointed net.cops who are to lazy to check up on facts that they personally don't agree to. As Patrick Moynihan famously said, "you are entitled to your own opinions, but you are not entitled to your own facts".

Fact; caffeine, like unfinished compost, inhibits seed germination and root growth.

Try a little harder to make yourself even more obnoxious. What you quoted above is not in the linked article, unless most likely I pay a goodly sum of money to get the whole report.
I get, from what is there, that they are referring to caffeine buildup in the soil of the coffee plantation, probably not of too much concern to most of us that do not dump tons of coffee waste on our soil.

Or perhaps the discarded stuff is chaff from the coffee beans? Our local Master Gardeners use that chaff as one of the ingredients to make their compost for their demo garden

It is possible that if you use large amount of unbrewed coffee, it can have significant amount of caffeine. But coffee ground waste (after brewing) will have very little caffeine left in it.

Maybe the coffee was brewed and they made instant coffee with it, but it looks like it is freshly ground? I can't imagine them not using it for something first, as others have already mentioned.

I would compost it first and use the raw material in small quantities on the plants themselves. By composting the coffee waste, you will eliminate any issues with acidity or caffeine. I use lots of used coffee grounds in my beds around my gardenias, camelias and palm trees, but only to a point as a supplement for which it has yielded very good results. The remainder I compost that makes some great finished compost in about 6-12 months.

Well gang here I am a year after my original post to let you know the results of using the coffee plant waste. I got fifteen five gallon buckets of the waste and used most of it sparingly in my compost pile along with pigeon, chicken, goat and rabbit manure. The other material used was mostly leaves collected and spent straw. The pile heated up normally and the finished compost did not have any adverse affect on the plants this past season. In addition to using the grounds in the compost pile I received several truckloads of wood chips and other tree trimmings. This is the first time that I have used the chips between my garden rows as mulch. My thought was that this might pose a problem while they were breaking down so I also sprinkled coffee grounds on them and continued to do so through the gardening season. .

Thanks for the update flavio. Always good to get the circle completed on these things, and now it's here as a record for anyone else who is looking for info.

Did you find out what exactly this material was? Brewed or unbrewed grounds, chaff, ??? I think with your great sounding mix of materials it wouldn't matter, just curious.

flavio, I have used green beans, roasted beans & grind coffee, chaff for years with great garden soil.

Only problem with my 6 compost piles is that the weeds can get 6 feet tall.

So I have to keep all CP clean of weeds. Did find a small(24inch) snake in one pile.