Coffee grounds are usually added as a soil amendment.  Uncomposted coffee grounds will not make a suitable growing medium.  You would have to compost them for months before using them extensively.  

Read through this page carefully: https://extension.oregonstate.edu/news/coffee-grounds-perk-compost-pile-nitrogen Especially note the paragraph about seed germination. 

Generally, you don't want a raised bed that is totally comprised of organic matter. Note the third bullet in this page about filling raised beds: https://extension.umd.edu/resource/soil-fill-raised-beds

Ellen