It takes the inventive mind of a deep-thinking stoner to construct an elaborate setup like this. I see two timers, an automated water pump, copious wiring, relays, and autonomous nutrient dispensers. I wouldn't be surprised to learn that this setup is capable of freezing passing UFOs mid-flight.
Yes, his creation does all of that. He is going away on vacation and the plant will be unattended for a week or two. As an engineer, he saw it as a challenge.