Sow is an agricultural term meaning to scatter seed over the ground for growing. This is the sense borne by the verb in the idiom sow [one’s] wild oats—though of course it’s metaphorical. The metaphor, which means to indulge in adventure or promiscuity during youth, traditionally applies only to males, but there’s no good reason to enforce this today.
Examples
Might as well make sure the boy doesn’t cause too much trouble while he’s sowing his wild oats, right? [Discover Magazine]
The son, it seems, hasn’t quite finished sowing his wild oats and isn’t really ready to settle down. [Mount Vernon Gazette]
[S]he’s suing her former fiance for at least $62,814 in wedding expenses after he got caught sowing his wild oats in Sin City. [The Consumerist]