In soil science, agriculture and gardening, hardpan is a general term for a dense layer of soil, residing usually below the uppermost topsoil layer. There are different types of hardpan, all sharing the general characteristics of being distinct soil layers that are largely impervious to water. Some hardpans are formed by deposits in the soil that fuse and bind the soil particles. Others are man-made, such as hardpan formed by repeated plowing or heavy traffic that compacts the soil.

Hardpan can be a problem in farming and gardening, by impeding drainage of water and restricting the growth of plant roots. In these situations, the hardpan can be broken up by digging or plowing. The broadfork is a manual tool specifically designed for this task; a digging fork or a spade might also be used. The chisel plow does a similar job with the help of a tractor.