Coffee grounds add nitrogen to the soil in addition to other trace minerals. They also help the soil hold moisture and add some acidity to the soil. (They will lower the pH level of the soil) I've also read in many places that the caffeine in coffee grounds act as a lethal neurotoxin for the control of slugs and snails.

Here is a link that might be useful: Controlling slugs with coffee

all additions of organic material are good for a healthy soil - grounds will not affect the pH level of a soil, as their pH is close to neutral - like any organic material they aid the tilth of the soil and provide moderate amounts of fuel for the soil microbes and are 'good' for any plants - roses seem to respond well to grounds spread as a light mulch around them

the FAQ for the soil forum has a section on grounds

Bill

Again, the caffeine in coffee grounds ends up the same place as all of the acid: in your coffee cup. The grounds do not contain enough of those chemicals to affect slugs. Some will swear that it works (for their slugs), and would be worth trying certainly. I can't help but think it's sort of like grits and ants: there is NO way that grits can kill ants but for generations some folks continue to swear it works!

There have been some studies done with caffeine, but the dose has to be pretty powerful, I believe. Anyway, as Squeeze says.....the grounds are a good amendment when used conservatively.

Alright... Fresh coffee grounds will add acidity to your soil because it has not yet been taken out from brewing. If you want to take care of slugs, you will need to apply grounds that have not been brewed. I've never heard of the "grits" thing but have seen some pretty convincing stuff about the slugs.

As I said, it is certainly worth trying....though I think that the used grounds are better for the soil and its' inhabitants than raw grounds. I've heard both sides of the story.....some that are convinced that slugs eat coffee grounds and others that swear that their slugs are slayed or at least repelled. I'M going to try it!

I checked my book, "Texas Organic Vegetable Gardening" by J. Howard Garrett, and it says: "Approximate analysis is 2-3-6. Coffee grounds are an excellent natural fertilizer with an acid pH and up to 2 percent nitrogen. Collect grounds at home and from your local restaurant or coffee shop and use in the compost pile or apply directly to the soil at 20-80 pounds per 1,000 square feet." BTW, it's an EXCELLENT book!

Thanks for all your replies! Very imformative. I am excited to hear that caffeine repels snails and slugs (Thanks Todd in Texas) We have quite a few in our garden..And I will try to look for that book Gardener972. I would like to know a little more about organic gardening. So far we just throw all the vegetable waste (peels, onion skins etc) around the plants and let it do its thing with the soil. I will be applying the coffee grounds to my plants, esp the roses. Thanks again :-)

So, if I'm reading this correctly I can put the coffee grounds (and tea leaves) right on to the soil and just mix it in?

yes, Beatle - just don't put thick layers as they'll form a crust and repel water

Bill

Here is a link that might be useful: starbucks take on grounds

Thanks Bill, I'll make sure I don't do that! I appreciate your quick responce!

Beatle