Different Types & Brands of Digital RH Meter 
_
_______
Relative humidity (RH): The amount of water in the air compared to the total amount
of water that the air can hold at a given temperature. (%RH = Amount of water in the air X 100 Amount of water possible at a given temp). As the temperature increases the amount of water that the air can hold increases. When the air is saturated water molecules condense. This causes clouds when at altitude or fog when near the ground. How does this relate to plants growing in a greenhouse?
*As the RH increases around the leaf (concentration of water molecules outside increases) it makes it more difficult for the water molecules inside the leaf to move out (transpiration) via diffusion.
*Therefore, as the RH increases, transpiration decreases, water and therefore nutrient movement decrease, and nutrient deficiencies can result.
*ALSO, as RH increases and transpiration decreases, leaf temperatures often increase, since transpiration is the plant’s way of cooling itself.
Optimum RH range for tomatoes (and most plants) = 55% - 95%
In USA & other other advenced Western countries during hot, dry weather, fan and pad cooling adds moisture to the air.
On hot, humid days, fan and pad cooling adds moisture but does not cool as well.
During cool, damp weather, RH inside the greenhouse can approach 95%.
of water that the air can hold at a given temperature. (%RH = Amount of water in the air X 100 Amount of water possible at a given temp). As the temperature increases the amount of water that the air can hold increases. When the air is saturated water molecules condense. This causes clouds when at altitude or fog when near the ground. How does this relate to plants growing in a greenhouse?
*As the RH increases around the leaf (concentration of water molecules outside increases) it makes it more difficult for the water molecules inside the leaf to move out (transpiration) via diffusion.
*Therefore, as the RH increases, transpiration decreases, water and therefore nutrient movement decrease, and nutrient deficiencies can result.
*ALSO, as RH increases and transpiration decreases, leaf temperatures often increase, since transpiration is the plant’s way of cooling itself.
Optimum RH range for tomatoes (and most plants) = 55% - 95%
In USA & other other advenced Western countries during hot, dry weather, fan and pad cooling adds moisture to the air.
On hot, humid days, fan and pad cooling adds moisture but does not cool as well.
During cool, damp weather, RH inside the greenhouse can approach 95%.
Posts
No comments:
Post a Comment