Clay soil has the smallest particles among the three so it has good water storage qualities. It’s sticky to the touch when wet, but smooth when dry.
Due to the tiny size of its particles and its tendency to settle together, little air passes through its spaces. Because it’s also slower to drain, it has a tighter hold on plant nutrients. Clay soil is thus rich in plant food for better growth.
Clay soil is cold and in the spring, takes time to warm since the water within also has to warm up. The downside is that clay soil could be very heavy to work with when it gets dry. Especially during the summer months, it could turn hard and compact, making it difficult to turn. (When clay soil is worked while it’s too wet though, it’s prone to damage).
If moistened soil feels sticky, rolls up easily, and forms into a ball or sausage-like shape, then you’ve got yourself clay.