Incandescent Jokes

Q: How many pot growers does it take to screw in a light bulb?
A: None, they use fluorescent bulbs instead.
Note: Fluorescent light is closer to natural sunlight than an incandescent bulb, so anyone using artificial light (which pot growers might do to keep their crops covered and safe from flying, prying eyes) to grow stuff would probably use fluorescent light rather than incandescent.