The reason we don't ever see them arguing is because it devolves into Moon Threats.
"Time to prepare for my British vacation. My only souvenir will be flaming vengeance."
— Garfield
I have reason to believe that last time Celestia and Luna got into an argument, Nightmare moon happened.
Agree with J Teeth, any pony could grow some plants, but EP's are the only ones that can grow stuff fast and in large quantities. As well as being able to grow in conditions no other pony could.
Build a fool proof system, and the world will create a better fool.
My random thoughts
OK, those are good points, but what about the 'instant growth' theory? It's hard to say weither it stands or not. The zap apple trees and that truth plant grew instantly, but they are already magical. Then AJ (as smart cookie) grew that plant right on her hoof...I just don't know what to believe.
Tealove is best pony.
Ask The Mane Six
Right. I think I have it then.
Tealove is best pony.
Ask The Mane Six
Only earth ponies have the ability to farm in such bulk quantities like, say, the scale of Sweet Apple Acres or the massive wheat fields outside Fillydelphia implied by the offical map, I reckon. Unicorns and Pegasi can grow plants, but not as expertly as Earth Ponies, also their cultural habitats don't leave much farmlands (Unicorns were said to live on mountainsides, Pegasi in the skies). Admittedly Unicorns could resort to cave mushrooms and mountainside crops, and Pegasi could eventually stumble upon the science of aeroponics, but neither seems to have come up in canon.
I would really like to know what insane unicorn thought that manually controlling the sun and the moon to begin with was a good idea.
Wow, I'm surprised, but kind of proud it took me a bit to get that picture.
On another note, man, those capes were bitchin'. I really hope they become this season's equivalent to the Gala dresses. They were way too cool to just be an end-of-episode thing.
Life is simple: it has no nontrivial normal subgroups.
Those capes are totally coming back for S3.