And Wikipedia reports differently:
"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 US gallons."
So I suspect there are no real industry standards here, to put it mildly.
"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 US gallons."
So I suspect there are no real industry standards here, to put it mildly.