In short, the answer to your question is “it depends”…!!
In terms of composting ingredients coffee grounds are classed as a “green” – full of Nitrogen. If you feel you already have enough “greens” in your compost mix (grass clippings, veg peelings, weeds etc,) then from reading the above replies it seems to me that it would make sense to spread coffee grounds on top of your soil. I have no experience of this.
On the other hand, if you have an excess of “browns” such as shredded leaves and twigs, straw etc then I think it would make sense to add it to these in the compost bin to get a nice balance (3 parts brown to 1 part green is a common estimate of this).
I don’t have access to horse or cow manure so I am making as much garden compost as I can by making it as quickly as possible using the “hot†technique. At the moment I already have a good balance of green and brown material for my compost bin but I continue to pick up quite large amounts of coffee grounds from our cafe at work. I add them to the compost as I give it it’s first turn – usually about a week after first making the heap. My theory is that the compost is thereby getting a big input of nitrogen for a second “stew†without further addition of complex plant material which would take longer to be broken down. If I did not have enough coffee grounds I use grass clippings instead as these also break down very fast.
I’m aiming to continue making compost into the winter for as long as possible (I am trying to think of ways to insulate my compost bins!) and whilst I will continue to have free access to shredded and partially-composted garden waste (brown) from the council I will find it difficult to get enough greens – so I will probably try mixing the browns with just coffee grounds (plus water and rock dust) as a first mix. I don’t yet know how well this will work out but it will be a fun project over the winter when there’s not much else to do in the garden – at least turning compost keeps you warm!!
Does that help?
Compostpope