How do you Lvl up the green thumb:Richard?

Stationing this hero will let you earn Exp for him when you do Rapid Production in the farms. This will increase the Heroes Level. You can also increase this quickly by using Hero Exp items from rewards. To do this go to the hero menu and tap on the hero then tap the Level icon.

To unlock and upgrade the heroes skills you need wisdom medals. Tap on the scroll icon at the bottom of the heroes screen to see the skills and tap each to see what you need to unlock or upgrade them.