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
Vapour Trail (song) Vapour Trail (song) "Vapour Trail" is a song by British shoegazing band Ride. It is the closing track of the band's debut album, "Nowhere" (1990), released on Creation Records, and was later released as a single in the United States in early 1991. Written by lead guitarist Andy Bell, the song features a distinctive swirling guitar riff, a strong, fill-based drum beat, and a coda that includes a string quartet. The song is the band's most well known and would later be voted number 145 on Pitchfork Media's "Top 200 Tracks of the 90s". "Vapour Trail" is written in standard