Vapour-pressure deficit the plant may dry out and die. For this reason the ideal range for VPD in a greenhouse is from 0.45 kPa to 1.25 kPa, ideally sitting at around 0.85 kPa. As a general rule, most plants grow well at VPDs of between 0.8 and 0.95 kPa. In ecology, it is the difference between the actual water vapour pressure and the saturation water vapour pressure at a particular temperature. Unlike relative humidity, vapour-pressure deficit has a simple nearly straight-line relationship to the rate of evapotranspiration and other measures of evaporation. To compute the VPD, we need the ambient (greenhouse) air
Aerated water Aerated water Aerated water is, correctly speaking, water to which air is added. The term is, however, frequently applied to carbonated water. Sulfur compounds dissolved in water are not necessarily dangerous, but can give the water a bad taste or foul smell. These compounds can be removed in several ways, the most effective being by exposure to chlorine gas. However, aeration can also be effective if the amount of sulfur in the water is relatively low. During aeration, water is pumped into a non-pressurized tank and agitated. This physically removes many of the sulfur compounds, which are then vented. Exposure