Short ones:
- Why did the potato cross the road?
He saw a fork up ahead.
- Why didn't the mother potato want her daughter to marry the famous newscaster?
Because he was a commontater.
A longer one:
An aging man lived alone in Ireland. His only son was in Long Kesh prison, and he didn't know anyone who would spade up his potato garden. The old man wrote to his son about it, and received this reply, "For HEAVENS SAKE, Dad, don't dig in that garden, that's where I buried the GUNS!"
At 4 a.m. the next morning, a dozen British soldiers showed up and dug up the entire garden, but didn't find any guns.
Confused, the man wrote to his son telling him what happened and asking him what to do next.
His son's reply was: "Just plant your potatoes."