I was reviewing the planter pots on Amazon when I came across this in one of the reviews: "A Trade gallon is a term used to denote the sizes of standard plant containers in horticultural industries. A trade gallon is equal to approximately .71 U.S. liquid gallons." I DIDN'T KNOW THAT. Since it is seldom that the pots one sees in garden sections are labeled with their gallon capacities, I've always determined their number of cubic inches and then converted this into dry gallons, using 268.89 cubic inches per gallon as the key. I have to wonder how widespread the practice is. I know a 2X4 isn't really 2" X4", but does this sort of deceptive practice exist in every industry? Is there anything that can be believed? More importantly, I'd just like to know if this labeling practice is universal throughout the nursery industry.
Is there such a thing as a "Horticultural gallon"?
Nursery Container Volumes:
Product Numbers, Dimensions & Volumes
Diameter x Height Volume Gallons Volume Liters
1T Trade 1 Gallon 6 1/2 x 6 1/2 0.75 2.84
2T Trade 2 Gallon 8 1/2 x 8 1.60 6.06
3T Trade 3 Gallon 10 1/4 x 9 2.80 10.60
3S Squat 3 Gallon 11 1/2 x 8 2.80 10.60
3F Full 3 Gallon 10 1/2 x 10 3.00 11.36
5T Trade 5 Gallon 12 x 10 1/2 4.10 15.52
5S Squat 5 Gallon 13 1/2 x 10 3/4 4.86 18.40
7T Trade 7 Gallon 14 x 11 3/8 6.20 23.47
15 15 Gallon 17 3/4 x 16 14.35 54.31
25 25 Gallon 23 x 17 3/4 25.70 97.31
Well, I don't know what to make of these figures. My question is still, is there such a thing as a horticultural gallon, which is in common, even universal, use? I didn't run all of them through my method, but my calculations for the first and the last two are as follows:
(1) 3.14x3.25x3.25x6.5/268.89=,803 US dry gallons
(9) 3.14 x 7.75/2 x 17.75/2 x 16/268.89=14.72 US dry gallons
(10) 3.14 X 11.5 x 11.5 x17.75/289.89=26.78 US dry gallons
I don't know what "T" refers to, and I'm not interested in liters.
Fraid so, Pop. All the shrubs I've purchased from nurseries or by mail order have come in pots closer to tapla's "trade" gallons than true liquid gallons. By the way, the volume figures in his list are slightly smaller than the volume you get if you calculate pi r squared x height, so I guess they are assuming the soil line doesn't quite reach the top of the pot.
Okay, now I what "T" refers to. Well, some people don't catch on as quickly as others. Still, that was dumb of me. Anyway, I'll stick to my method, except that I am going to create a table that shows the gallonage, dry gallonage, of the most commonly used sizes. Why bother? Simply because most of the pots/tubs/vessels I see at Home Depot don't even mention their capacity. As far as the pots I see for sale on Amazon, I'll just have to keep Trade practice in mind. It makes me wonder, though, in how many other industries are their sizes not the real sizes.