|Akiros Ismort, the Fallen|
It is mid-spring (April-ish in the Northern Hemisphere--The Stolen Land sits about at the level of the northern tier of the U.S.), but you would need to clear, flatten, and plow the rough landscape (requiring a plow at minimum, and usually some horses or oxen), have the right seeds, and actually know how to farm. Most of these folks are more on par with 'farm hands' rather than actual farmers. Remember too, the fort is really more of an open-air ruin than a fort, and most of the bandits don't have much in the way of engineering skills (as attested to by the condition of their lair).
As a side note, I should point out that as bad-ass as Akiros is, he is an paladin/barbarian classes not really known for their technical skills.