Greenhouse technology is an effective method of cultivation of flowers, crops, etc. under controlled environment. For any greenhouse, ventilation performance is a major factor in production, influencing the yield and quality of the products. Natural ventilation can be effectively used to maintain greenhouse microclimate, conducive to plant growth, when the ambient conditions are not extreme. The present paper discusses the modeling aspects of a floriculture greenhouse suitable for operation in typical Indian climate under natural ventilation. Combined ridge and sidewall ventilation is considered in the model. The model is validated against the test results of an experimental greenhouse. Parametric analysis is also done to understand the effects of variations in parameters such as wind speed, solar radiation intensity, effective greenhouse height etc. The study reveals that the performance of a greenhouse under natural ventilation is influenced considerably by parameters such as intensity of solar radiation, effective distance between the side and the roof vents, free wind speed etc. (C) 2008 Elsevier B.V. All rights reserved.