I have used UCG as a mulch between rows of carrots as an odour mask against carrot rust fly. It's doubtful if it worked. The odour dissipates quickly and I didn't re-apply often enough.

The carrots grew fine and the UCG was tilled in this spring. I can only believe that it has had beneficial effects for the soil.

Some people have reported that coffee grounds can form a crust when they get very dry which will shed water and is hard to wet again. Watch out for that if you use them. You can mix them with something else or cover them with a layer of another mulch to keep that from happening. I haven't use them, just reporting what I've seen here.

thanks for both of these comments to my post! I had forgotten about them drying and forming a crust, I remember reading that as well some where.. maybe I will just stock pile them and when the garden is ready to be tilled I will spread them, then.

If you want to use them now, just apply and scratch them into the soil a bit; that's all it takes to keep a crust from forming.

Gary

From Linda Chalker-Scott, "The Informed Gardener", comes the following recommendations on UCG as mulch:

⢠Coffee grounds are finely textured and
easily compacted.

⢠Compacted coffee grounds create a
barrier to moisture and air movement,
especially when applied in thick layers.

⢠Therefore, I recommend against
using pure coffee grounds as a mulch;
instead, try using a thin layer (no more
than half an inch) of coffee grounds
and cover with a thicker (four inches)
layer of coarse organic mulch like
wood chips.

Full article available from the link below.

Here is a link that might be useful: Coffee grounds

This post was edited by TXEB on Tue, Jul 9, 13 at 7:50

Uncomposted coffee grounds don't make a good mulch, but they are a heck of a good soil amendment.

Just mix them into the soil instead of leaving them on the surface and instead of being water repellant they become water retentive.

Also, they summon crowds of earth worms which absolutely adore them as a food source. The worms will loosen and aerate your soil as well as leave behind worm poop which is an awesome organic fertilizer.

Can you find some fallen leaves and grass clippings? Voila you have compost!
Just mix it up with a bunch of other stuff and you'll be happy! Nancy

I remember someone posting pictures of their coffee grounds + shredded leaves used as mulch. It looked great, I don't know how thick it was though.

I have used coffee grounds on many planting beds but never as the sole type of mulch and never thick enough to crust over and prevent rain, or water from any other source, from getting through to the soil. Even with 10 pounds of coffee grounds I did not have enough to cover the soil more than 1/8 inch.
Coffee grounds are a good source of Nitrogen with some P and K, 2.0-0.3-0.3 and a pH in the 6.5 range and a C:N ratio of about 11:1, so they are a good soil amendment. If you have a very small garden or pick up a truck load of coffee grounds I think it would be difficult to have enough to cover the soil 1/2 inch deep.

Thanks again for the great info, I haven't been able to check this forum for several days, and like magic, more useful information!

I sprinkle my used coffee grounds over my lawn as well as my garden beds.

I will periodically get grounds from a local coffee shop and sprinkle them over my mulch. Seems to make the garden look a bit more freshly mulched.

I like using them as a thin mulch in my baby palm tree seedling bed and using them as a soil amendment that it is tilled in with my Mantis Tiller.

BTW: I have never had a problem using them as a thin top dressing especially around my gardenias and camellias. They really like the used coffee grounds.

Unless you visit a lot of Starbucks, the coffee ground coming out of your coffee maker is not going to be significant to mulch to a thickness of over 1/2 inch.
I use it in a recipe to make slug killer. I add little bit of sluggo type bait, play sand, ground eggshell saw dust. Voila! And use it generously around the seedlings. Slugs hate rough surface to crawl on. If they do, they will bleed to death. Things like coarse stone dust is also good to mix in.