How about starting with "unpowered" grennhouse that only works during the day using natural sunlight. A little power could be used to plant seedlings, harvest trees and pull out weeds. But way less than now. Speed would be 60% from now.
The next tire could then be lights at night. This could used increased power at night and extra pollution at night.
An additional tire could be to use extra light even during the day and increase the CO2 content of the air. So the greenhouse would need 2 pipe inputs, one for water and one for CO2. It could have a third pipe to output excess O2 but that would probably be anoying to connect pipes to.