Sowing wild oats

I'm pretty tired, so this is going to be a copy-pasted explanation from Wikipedia (sorry):

"Sowing wild oats" is a phrase used since at least the 16th century; it appears in a 1542 tract by Thomas Beccon, a Protestant clergyman from Norfolk. Apparently, a similar expression was used in Roman Republican times already, e.g. by Plautus. The origin of the expression is the fact that wild oats, notably A. fatua, are a major weed in oat farming. Among European cereal grains, oats are hardest to tell apart from their weed relatives, which look almost alike but yield little grain. The life cycle of A. fatua is nearly synchronous with that of Common Oat (see also Vavilovian mimicry) and in former times it could only be kept at bay by checking one's oat plants one by one and hand-weeding the wild ones when they were in flower but the grains had not ripened yet, lest the wild oats seeded themselves out. Consequently, "sowing wild oats" became a way to describe unprofitable activities. Given the reputation of oat grain to have invigorating properties and the obvious connection between plant seeds and human "seed", it is not surprising that the meaning of the phrase shifted...''