depends on what your soil ph is and what you plan on growing.

I would use them for the compost, before adding them in the garden. I believe that the compost can almost neutralize and buffer the starting raw material. The compost is much more forgiving than the garden. For example, You could throw fresh manure on the compost and have a perfect compost, you throw the same fresh manure on the garden, you could end up with disease wiping out all your garden.

Additionally, how large of an area are you talking?

25 gallons per week is a lot of UCGs.

Lloyd

Coffee grounds, as determined by numerous soil test labs, are in the 6.8 range, fairly close to neutral. You will not need to add lime because of the coffee grounds but other factors may require that you do. Have a good, reliable soil test done before adding any lime, however.

i had gotten about 100+ lbs from starbucks over the winter.
i had mixed it in the soil in 2 areas i plan on planting Papaya.

Its not bad if you break it up and mix it in well, and it has a couple of months to break down.
some of the stuff on top turned a brown (lighter) color, it seemed it went through a chemical change. that was the stuff in the sun though.

They seem to do well when mixed in with leaves and dry grass.

supposedly there is a chemical in it that can stunt growth
so i (now) only use after composting, and less than %50 grounds.

theres a few threads here that may be of interest...

growth inhibitor in uncomposted coffee grounds?

Here is a link that might be useful: forums2.gardenweb.com coffee+grounds