The Farmers Dilemma

An old farmer wrote to his son in prison. "This year I won't be able to plant potatoes because I can't dig the ground, I know if you were here you would help me." The son wrote back, "Dad don't think of digging the ground because that's where I buried the guns." Police read the letter and the very next day the whole ground was dug by police looking for guns but nothing was found. The next day the son wrote again, "Now plant your potatoes Dad, it's the best I could do from here..