Science Forums 2

[Michaelangelica]

Originally Posted by chrisbrandow

I was wondering about the common practice of adding coffee grounds to soil. As I understand it, they can be 20-30% carbon, depending on how dark the roast. Perhaps the carbon content plays a role. For the home gardener this might be a simple way to add carbon.

You could be right. I don't know.Certainly one for Cornell Uni to experiment with.Although Coffee Grounds have a carbon-nitrogen (C-N) ratio of 20-1, this is not charcoal-carbon which Terra preta seems to need.
They are still good to use in the garden Here is some web links I found:-
.

Coffee Grounds 2 0.3 0.2 Highly acidic, best for use in alkaline soils

.http://www.ibiblio.org/london/permac.../msg00085.html
As biofuel
http://72.14.209.104/search?q=cache:...ient=firefox-a
In compost
http://www.newsflash.org/2003/05/si/si001535.htm

When used properly, coffee grounds can act as a green material with a
carbon-nitrogen (C-N) ratio of 20-1.

helping salty soil (This is a good use)
http://www.stansw.asn.au/ys/mcleod.htm

organic content (Coffee grounds) of the soil had a protective effect on salt toxicity to carrots.

Coffee grounds as fertilizer (A good gardening site too):
http://www.backwoodshome.com/articles/nyerges44.html

Used coffee grounds contain about two percent nitrogen, about a third of a percent of phosphoric acid, and varying amounts of potash (generally less than one percent). Analysis of coffee grounds shows that they contain many minerals, including trace minerals, carbohydrates, sugars, some vitamins, and some caffeine. They are particularly useful on those plants for which you would purchase and apply an “acid food,” such as blueberries, evergreens, azaleas, roses, camellias, avocados, and certain fruit trees.

We dry our coffee grounds in the oven, too. Then we scatter them lightly, as a mulch, around those plants which we feel would benefit from them. We don’t scatter them thickly when they are wet, because the coffee grounds have a tendency to get moldy.

The growth of plants that like or need lime (which we can provide with eggshells) can be stimulated by adding a mixture of ground-up eggshells and dried coffee grounds.

In Commercial Mixes
Grow Joe Fertilizer:
http://growjoeplantfood.com/coffee.html
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PS
Just had another thought re DIY Planet Coolingthread.
If we all collected Coffee grounds from GJ's and Starbucks (who it is said have a policy to give C.G. to gardeners -yes Star an GG's are breeding here too!) we would be helping to cool the planet.
My reasoning:-
Coffee grounds otherwise go to landfill, and break down anerobically causing methane gass a major green-house gas.
(Landfills are the major source of methane)