I always think of my Dads garden when I see pictures of yours. His was on the side of his Chicago backyard next to the garage and was about as wide and long as yours. For manure he would take a shovel and drive a mile or so across the Indiana border where there were some riding trails. Open the trunk and shovel it in.
Dear old dad! I worked at a family-owned (not mine) dairy farm (approx. 300 Holsteins), prouder/retailer in the late 60's and early 80s (many stories, by the grace of God, just ask) and could get manure for free, yet had no garden. But my dad made a small one when he retired, and so I asked the boss if I could borrow a dump truck and have a worker (binge alcoholics) get some manure. The worker asked me if I wanted one or two scoops of the front-end loaded. Two are better than one I thought.
Well, I drove it home, about a mile the way the crow flies, and dumped it off to the side of the front yard and left it there and went back to work at the dairy (deliveries). Well, working at a dairy farm you kinda get used to the homey smell, and the manure was still rather "ripe" as we say, but a close neighbor couple did not share my tolerance to this fragrance, and reasonably objected. And mom said that she could smell it from the bottom of the hill we lived on.
So I got the wheel barrel and put 25 loads on dad's approx. 20'x12' garden. And only half was gone. So I found another spot, and my younger brother took some to some friends of his (they remained so), to help grow food, and thus the cycle of nature was complete.
As said, lots of memories (I can remember at age 73 - likely about average on FR) thank God. Yet ice cream melts, and souls live forever, and God later called me to leave all in '86 to serve Him for free. Thanks and glory be to God in Christ