Propagating mint in water

I was somewhat sceptic when I was told that if simply stuff in the mint stalks you buy at the farmer's market into soil it would grow and invade the pot: I googled on and I read that it would be safer to root the stalks using the water method to make sure it would survive in the soil.

I followed instructions here and also drew analogies from here, it is day 3 for my mint stalks and to be honest I'm getting dubious about this method, though everyone claims it to be foolproof. Indeed, at the bottom leaf armpits which I had diligently removed before putting into water there seems to be a sign of new life, but it is not a root!!

We'll wait and see. My cut off date is in a week's time...