We have clay soil where we live. Clay soil is good for making adobe and pots. I don't want to make adobe or pots so our soil is kind of useless. It is hard as a rock when dry and super sticky when wet. In its natural state it is not very good for growing a garden.
So I have been creating an unnatural soil. I'm shovelling in compost and gypsum to break up the clay and provide nutrients for our garden. It's a slow task but I figure within the next five years we will have nice rich loamy soil for our garden.
The earthworms are helping too.