Understanding plant responses to environmental factors is crucial in controlled environment crop production. This chapter summarizes current understanding of interactions of key aerial environmental factors affecting plant growth and their strategic applications to improve the productivity, profitability and sustainability of greenhouse cultivation. It reviews the current body of knowledge regarding plant responses to environmental interactions. Environmental factors discussed include light intensity, temperature, air circulation, relative humidity and carbon dioxide concentration. Interactions of (1) light and temperature; (2) light and carbon dioxide; (3) light and plant canopy structure; (4) temperature and temperature integration time; and (5) humidity, air circulation and light are also presented (it must be noted there are many other combinations of factors, not only of aerial factors but also of root-zone factors). A case study is provided on tipburn management of strawberry using night-time humidity control. The chapter concludes with a look towards future trends in research.