That's pretty good never really tried anything like that for 2 reasons
1. Don't want to mucky up my Charger
2. Don't think it would work (Previously)
Plus I think my Charger would break a tomato in half, 3 pins on them (Being a Brit), we have Earth pins on them just above the 2 pins you have on the charger in that video (I'm guessing your European? by the look of that Plug, Maybe American I think they use 2 pins as well).
But good, might try it with one of my old phones, my mum has got some tomatoes growing might nick one of those and try it in a few days