Outdoors it's possible to grow most crops with a visit once a week, or even less. Under cover, unless you are ruthless with your planning and invest in automatic systems, you MUST visit more frequently, probably at least twice daily, and preferably more often. Outdoors we can often rely on nature to provide the water and change the air as our plants require. Under cover we are in charge and must do these important tasks not only well, but also with monotonous, unbroken, regularity.