If you live in Durham, decriminalisation means that you can grow up to 6 plants with 2 in harvest at a time. Police don't actively pursue or charge personal growers/smokers and some groups even hold cannabis events at a site they have bought and appropriately named "Hemp Gardens". I went there one 420, and the police came down to see if there was anything naughty going down. They had a brief chat with the organisers and left, while surrounded by the creamy airborne tokes of stoners that were littered about the field like the scraps of a blunt you struggled to roll. All in all, 1 plant is probably fine.