VPD, or vapor pressure deficit, is a measure of the difference between the amount of moisture in the air and the amount of moisture that the air can hold at a given temperature.
In the context of cannabis cultivation, maintaining the right VPD is important because it can affect the rate at which the plants transpire, or lose water through their leaves. A VPD range of 0.8–1.1 (kPa) is ideal in the vegetative stage, while a VPD range of 1.0–1.5 (kPa) is ideal in the flowering stage.
If the VPD is too high, the plants will transpire at a faster rate and may become dehydrated. This can lead to reduced growth and yield, and can even cause the plants to become stressed or die. On the other hand, if the VPD is too low, the plants may not transpire enough and may become waterlogged, leading to an entirely different set of problems like mold and rot.
Erratic VPD
Sub-optimal conditions lead to out-of-whack VPD and unhappy stomata
Stable VPD
With conditions in check, you can see that the leaves look much healthier.
Controlling VPD
By controlling the VPD, we strive to optimize the growing environment for our cannabis plants and help ensure that they grow and develop properly. This helps maximize yield and dramatically improve the quality of our final product. However, if the VPD fluctuates frequently or erratically, it can be difficult for the plants to maintain this balance. This can cause the plants to become stressed, which can negatively impact their growth and development.
For example, if the VPD fluctuates from very high to very low on a regular basis, the plants may not be able to transpire at a consistent rate. This can lead to inconsistent growth and development, and can ultimately reduce the yield and quality of the final product. Our stable and consistent VPD control supports healthy transpiration and optimal growth and development of our cannabis plants.
Bright lights, big sweaty
In a high PAR (photosynthetically active radiation) environment, plants are able to photosynthesize at a faster rate and produce more energy. However, this also means that they will transpire at a faster rate in order to maintain a balance with the surrounding air. In order to support healthy transpiration and optimal growth and development of cannabis plants in a high PAR environment, it is even more important to maintain tight control over the VPD. This will help ensure that our plants are able to transpire at a consistently high rate and maintain the optimal balance between moisture and evaporation.
