Plants are essentially biological pumps. Plants loose moisture from stomata on the leaves, resulting in osmotic pressure which pulls water and nutrients all the way from the soil via the roots and up the stems and into the leaves.
 
When cultivating crops like cannabis in controlled environments, all this moisture transpired from the leaves, is essentially "pumped" or dumped into the greenhouse or indoor environment. If you don’t manage this moisture, you will limit your growth potential and potentially place your crop at significant risk. 

Getting humidity right means that:

- Your plants can keep their stomata open to maximize CO2 intake.
- Transpiration is optimized, so the “pump” keeps working and water and nutrients are moved effectively from the roots to the leaves.
-  Your environment isn’t suitable for Botrytis and mildew growth.

Before we delve into humidity further, perhaps let’s get some terminology right.

- Relative humidity (RH) = The measure of water vapour in the air, relative to the total amount of water that the air can hold at a given temperature.
- Dew Point = at a certain temperature, the water vapor in the air is no longer held in a gaseous state, but starts to condense into liquid as mist, fog and water droplets on your plants, flowers and facility surfaces.
- Vapour Pressure Deficit (VPD) = The difference between leaf moisture and air moisture. When VPD is low (humid air), water is not removed from the stomata and the “pump” stops and nutrient uptake slows. When VPD is high (dry air), plants risk losing too much water, which causes stress and wilting and slows growth.

Dehumidifiers should be used in your cultivation space to manage VPD and reduce humidity risks. Keep tuned for the next features on humidity and dehumidification.

Part 2: I will discuss how dehumidifiers work and Quest M-Corr technology, separating AC and dehumidifier functions and calculating dehumidifier load.Part 3: Takes a deep dive on best VPD practices for each growth phase, dehumidifier applications in different types of facilities and localities in SAPart 4: Applications for Quest in Drying rooms
Part 5: looks at cost of ownership and the financial impact of investing poorly. I will also include many testimonials from Quest customers in SA.

Stay tuned and contact me brett@hydrobiz.co.za or my team at info@hydrobiz.co.za for more information.