I live on a 6 acre hobby 'farm' and have had a huge garden in the ground in my own native sandy loam here... but the only good pepper plants I've ever managed to grow were grown in partially composted coffee grinds mixed about 50% with sand... in pots.
But that was when I worked at the Google Waterloo office and could get as much a quantity of grinds as I wanted from the cafe there. Wish I still had access to that. 1 day of grinds was a 5 gallon bucket!
Every coffee shop I've worked at had someone who would come by and pick up the grounds every few days. It was always clearly just some guy who had a never-commented-on-or-explained arrangement with the owner, rather than like a company using it for commercial compost. You might be able to ask around and get a similar thing going?
Also even years later I strongly believe that, somehow, a trash can full of espresso grinds is the heaviest material in the world. Shit's denser than lead idk.
We’ve been able to just call up the local Starbucks’ and usually at least one is happy to give theirs, last time we went 4/4 and got more than we knew what to do with.
But that was when I worked at the Google Waterloo office and could get as much a quantity of grinds as I wanted from the cafe there. Wish I still had access to that. 1 day of grinds was a 5 gallon bucket!