Greenhouses create an optimal growing environment for crops through climate control and protection from harsh weather and pests. This research project assessed the current challenges that exist within the protected agriculture industry and developed a new greenhouse design accordingly. The work focused on a new method of greenhouse cooling, for use in warm climates. A strong emphasis was put on affordability, ease of access to technology, and water and energy efficiency. The result of this research is the Natural Ventilation Augmented Cooling (NVAC) greenhouse. The NVAC greenhouse is naturally ventilated and improved by augmenting the thermal buoyancy and wind effects with a strategically placed misting system. The greenhouse structure is comprised of tall sidewalls, oversized side vents, a roof vent and an additional inside roof. The misting system is located above the gutters of the greenhouse and sprays a mist of water horizontally between the top roof and the added inside roof. The added roof guides the cooled air to the plant space and prevents water droplets from reaching the crop foliage. Test units were built a) at the Macdonald Campus of McGill University in Ste-Anne-de-Bellevue, QC, Canada b) in Trents, Barbados and c) in the controlled environment of a research greenhouse at the Macdonald Campus of McGill University. In its final design under field conditions, the NVAC greenhouse provided temperatures 1.3 to 3.6 C cooler than outside temperatures, while increasing relative humidity by 5.7 to 17.7%. This is in contrast to inside temperatures being warmer than outside conditions in most natural ventilation greenhouses. The temperature response was rapid, dropping by 3.3 C within 120 s after activation of the system. Under field use, the NVAC greenhouse used 5.6% of the electricity required to run a pad and fan system in a comparable greenhouse. Under the low wind conditions of the controlled environment research greenhouse, the cooling performance of the NVAC greenhouse design varied from 1.9 to 12.6 C while the relative humidity increased by 1.4 to 31.2%, depending on the ambient conditions. Accordingly, the NVAC greenhouse was able to reduce the vapor pressure deficit (VPD) by 0.3 to 4.9 kPa. It was shown that the NVAC greenhouse can provide air movement in the plant space of the greenhouse at velocities up to 0.40 m/s without the use of fans. The conditions provided by the NVAC greenhouse offered an improved greenhouse climate in terms of plant growth and plant stress by means of cooling and an increase in relative humidity. In contrast to conditions of high temperature, the photosynthetic rate (Pn) in mature and fruiting bell pepper (Capsicum annumm, var. Bell Boy) was 28% higher under NVAC system conditions. Plant fluorescence (Fv/Fm ie ratio of variable to maximum chlorophyll fluorescence), an indicator of plant stress, was not depressed and the transpiration rate of the plants was reduced, by an average of 31%, with the use of the NVAC greenhouse. By monitoring diurnal tomato fruit growth, it was found that the NVAC greenhouse moderated the plant water status and prevented fruit shrinkage. By means of the cooling and humidity control of the NVAC greenhouse, the diurnal fruit growth patterns were more uniform in comparison to hot, harsh conditions. Under low wind condition, the NVAC greenhouse is capable of providing an improved climate that is comparable to that provided by pad and fan and fogging systems, and offers advantages over these traditional systems such as prevention of foliage wetting. The NVAC misting system can be used either intermittently or continuously to …