My Mom was into organic gardening long before it became really popular. Like I am talking about forty or more years ago. We did not have a garbage disposal, but did not need one.
All vegetable peelings, and left over greens, like the outer leaves of cabbage was all cut up and buried in a spot in the yard. This included egg shells, and coffee grounds. Then, when it was time to plant things in the spring she would use the dirt from that area. Let me tell you, she had one great green thumb.
She also made her own organic earth. I don’t know her formula, but she would take the earth, and add bone meal, and other stuff, then she baked it in the oven to sterilize it.