Origin of the phrase "sow wild oats"

In Collin's dictionary, to sow your wild oats mean

If a young person sows their wild oats, they behave in a rather uncontrolled way, especially by having a lot of sexual relationships.

What is the meaning behind the expression “sow wild oats”?
Where did it come from? Why was “wild oats” chosen?

According to etymonline.com,

Wild oats, "crop that one will regret sowing," is first attested 1560s, in reference to the folly of sowing these instead of good grain.

It is less clear when the meaning changed to its current one. That is, currently, to "sow wild oats" normally means (for a man) to have sex with as many women as possible. "Wild oats" here specifically means hypothetical unwanted offspring.

Here's a decent primer on the idiom: http://www.worldwidewords.org/qa/qa-sow1.htm

Wild oats are a weed whose seed looks a lot like certain cereal grains, and is thus hard to separate when sowing. Quoth the webpage:

So sowing wild oats was the archetypal useless occupation, indeed worse than useless. It’s not surprising that the phrase sowing wild oats was applied figuratively to young men who frittered away their time in stupid or idle pastimes.

So it's pretty much the same meaning as 1542, the first known usage, with perhaps a little more promiscuous sexual connotation these days.