What if you only have two-hundred pounds of seed, though? I may not know much about farming, but I do know that one needs two-hundred pounds of seed to upgrade a mace or make a statue.
Then I won't have to worry about little Ghreyfain's running around, will I?.
The better comparision Jason should've made was with cattle or hogs.
I didn't know you could upgrade the damned MoD until I read a Dan Simpson's WT.
For first time players - you're best off doing what Jester did: packrat
EVERYTHING you find. Stuff it inside one of the tables/barrels/crates in Athkatla. I typically use the ones in front of the Copper Coronet.
Other than becoming a packrat, (and reading WT) the only in game way to find out about the upgrade is to stuff MoD in the bag of holding and talk to Cromwell. IIRC, he digs through your stuff and mentions something about needing a special metal. And depending on your style of gameplay (ie: how fast you save Imoen), reloading from a save isn't always a choice.
I do agree that making the choice is very roleplay. What's more important to your PC: helping the temple of Helm (and thusly increasing the workload of countless acolytes and workman's comp. suits due to repetative stress disorder from polishing) or sticking it to a snooty 'ar-teest' by blagging him the wrong material?