Apparatus system and method of maintaining differential atmospheric control with respect to CO2 and O2 gases in a first, stem/leaf zone, Z-1, of a plant from a second, root zone, Z-2, of the plant. The atmosphere in a stem/leaf zone is controlled to be high in CO2 while the root zone Z-2 is isolated and provided with ambient or higher O2, at a pressure to prevent infiltration of CO2 from zone Z-1. The differential atmosphere in each zone can be selectively monitored and adjusted to provide improved growing conditions. The inventive plant environment control system and method is particularly useful in the field of hydroponic and aeroponic growing enclosures, wherein nutrients are periodically provided to the roots, and a high CO2 atmosphere, plus heat and light of appropriate growth-enhancing wavelengths, are provided to the leaves for forced, high-yield growth of selected plants indoors, regardless of the season.