Rods, poles and perches
The ancient measures are not without their content of confusion. An acre of land in Great Britain was traditionally 4,840 square yards in England, but in Scotland it was 6,150 square yards and in Ireland 7,840 square yards. There is a very interesting account of the way in which many measures tie to the acre at http://www.baronage.co.uk/bphtm-02/moa-10.html which makes good reading for an idle few minutes. Even current terms can be contradictory: I learned as a child in England that "a pint of water weighs a pound and a quarter," only to be told categorically when I reached the United States "a pint's a pound the world around."
A more encyclopaedic listing of many measures is at http://home.clara.net/brianp/. It is British based, and is a quick source for odd words that crop up in fiction and nonfiction from the old country.
How does this fit into a horticultural magazine? Well, to be honest, I can only say that it is my magazine to do with as I please, and what pleases me this time is this little diversion. My readers are smart enough to stop reading if the first paragraph doesn't seem interesting, and the consummate argument - the price of the magazine is right. So there.
I can slide back, though, by pointing to a part of the title which relates to the land on which we dig. A rod (which is the same length as a pole or a perch, 16.5 feet), is a frequently used measure in surveying - four rods make one chain (22 yards), 10 chains make a furlong, and 8 furlongs make a mile. But the final one of this trio is the really interesting one, and this information is courtesy of Michael Quinion's great site (http://.www.quinion.com). A perch is, of course, 16.5 feet long, but is also a square measure (160 perches make an acre) and has in the distant past been a volume measure for masonry at 24.75 cubit feet. Add to this its use as a name of a fish, and the thing on which a bird stands/sits, and you have a word with about as many meanings as another of my favourites, cob. How many can you come up with for that ? (I know seven offhand, all connected with the countryside.)
Since I am harking back in time, let me end with the old civil service closure to letters (Am I cynical in thinking that it was a sardonic statement?) Here goes: