My grandmother told me, as quite young child when I "helped" in her garden, that the most important thing about gardening was to take care of the worms. Feed them. Make sure that they had water. Make homes for them in the soil. Give them shade from the sun. In my mind I can still hear her saying, "It's time to feed the worms."
I learned to feed the worms by digging in grandmom's kitchen waste. I learned to keep the soil moist, but not wet enough to drown the worms. She showed me about
compost, which she dug into the soil to "make worm homes". She taught me that mulch gave shade for the worms.
Grandmom may have been not known the science behind what she did, but by caring for the worms she did everything right in order to have a robust garden.
My mother became an avid food gardener, but that was after I had moved away from home. But she apparently learned from her mother the same things that I did, because she had a successful garden. She was a big believer in horse manure. I saw the success she had using it, so to this day I use plenty of manures, horse included.