Trade gallon

A trade gallon is a unit of volume for standard plant containers in the horticultural industries. It equals 3 US liquid quarts or 0.75 usgal,  although some sources state that a trade gallon equals 2.7 L.

Notably, 10 trade gallons equals 30 US quarts, which in turn equals 1.0 cubic foot, a common unit of measurement for soil.