Q.Composting
The soil in my backyard in National City, California is very hard because of the lack of rain. At the same time I have a bad back and taking care of a compost bin or pile, least of all turning it over, is hard for me. So what I did is to limit the number of holes that I can plant in. At the end of harvest, I would dig up the already softened hole and slowly fill it up with all the food scraps, veggie and fruit peels and stuff on the hole and cover it with dirt. By April I plant on it. Am I doing it correctly?

This article has great information on trench composting.
https://www.gardeningknowhow.com/composting/basics/trench-composting.htm