How Natural Ventilation Works in Greenhouse

Natural ventilation in greenhouses functions primarily by wind blowing in one side and out the other. Wind can also create a vacuum pressure along the roof to “suck” the air out while letting air in the same vent or into the side vents. A secondary, much smaller effect is that of buoyancy, which predominates on hot, low wind days. In all cases, it is important to have at least one very effective inlet with multiple outlets; and that the air moves from inlet to outlet through the plants for good ventilation. For gutter-connected multi-spans, a combination of windward side vents and continuous leeward roof vents tends to result in the most effective ventilation design. For retractable roof designs, open windward side vents are as important as the open roof area to achieve mid-summer cooling.