Clay soil is sticky, smooth and heavy when wet and contains at least 25% clay. It’s easily rolled into a ball shape in your hand. It retains a lot of water resulting in poor drainage and is slow to warm up in spring delaying plant growth.
Solution: Add plenty of organic matter to break up the solid structure. It will need a lot of work but if you persist the clay will become easier to manage. On the plus side, it’s richer in nutrients than some other soils.