My garden is a raised box about 16 feet by 5 feet. The normal soil where I live is river bottom land...very fertile... and my box has a mix of that soil, some bagged soil, cow manure, chicken manure, soil conditioner and some black loam left over from putting in a new lawn. Brings it up to about 18 inches above the yard.
Everything grows great in it. The only failure I have had was the carrots last year but I think Red_Devil 232 pointed out my problem as growing season is hot hot hot in the Northern California valley interior.
Gotcha! Red Devil knows his stuff! He is the “oracle of gardeners!” (don’t tell him that because he blushes VERY easily! LOL!