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  • Topics

  • Posts

    • MrSlatersParrot
      VPD is another way to measure humidity. You can't measure it directly, it has to be calculated. It's a better way of setting the humidity levels if you're comparing grows at different temps.   For plant growth the leaf temp is often taken into account because it's cooler than the air if the plant is transpiring effectively, because of evaporation. An IR thermometer is a useful thing to have.   If you know that your plants want eg 25°C and 60% RH then give them that, you don't really need to worry about VPD. There are online calculators that let you play with this if you want.   Transpiration is affected by different humidities, too dry and the plant will try to close it's stomata to limit water loss, which also limits gas exchange and therefore CO2 intake, so photosynthesis is reduced, too humid and the water doesn't evaporate off the leaves fast enough and transpiration is reduced and so is growth.   Plants do transpire in the dark, I believe about 10-15% of lights on rate.    
    • Saddam
      It's Rogue One, bro.
    • Acl70
      Yes back in the early 90s
  • Images

  • 125 Cream of the Crop - February 2024

    1. 1. Please vote for your favourite photo


      • Jon Smith
      • murphyblue
      • Shumroom
      • Killuminati7
      • Military Grade
      • Rednose
      • Văru'
      • Wag
      • Ned The Head

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