lol - I don't grow (obviously) but I know people who do (legally). They don't use LEDs, but I did use LED lights to grow some indoor veggies. From what I read (again I'm no expert) the low end LED stuff just doesn't cut it. Maybe there's a high-end LED market I'm unware of?
If you could design an algorithm for your wardriver gear, you might be able to detect when growers switch from 18/4 to 12/12 hour light cycles.