Climate control is an integral part of modern cultivation. You can find these systems in greenhouses, indoor growing spaces, hydroponic operations, vertical farms and more. In most cases, this includes humidity control and air circulation, which drastically reduce disease outbreaks and crop loss.
Humidity control, nutrient transport and plant growth
The amount of nutrients a plant absorbs is largely what determine its growth. These nutrients are found in the soil or growing solution. So when plants uptake water through their roots, they receive these essential materials.
The plant transports this nutrient-rich water throughout its body, absorbing the different nutrients where it needs them. The plant eventually evaporates the excess water through the leaves.
This transpiration of water vapor, from the leaves, creates the force that sucks in water through the roots. This is the xylem pull. The faster the transpiration – the faster the plant takes in water and nutrients. When evaporation slows down, or ceases, so does the water uptake.
This is where humidity intersects with plant growth. Humidity directly affects the transpiration from the leaves. When relative humidity is high, meaning there is a lot of water vapor already present in the air, the rate of water evaporation slows down. This can also be described as low VPD (vapor pressure deficit). When the air is relatively dry, meaning VPD is high, the rate of transpiration goes up.
Many modern greenhouses adhere to the practice of plant empowerment, often referred to as next-generation growing. This cultivation theory emphasizes the optimization of plant growth. One of the major parts of plant empowerment is greenhouse climate control, specifically humidity control.
Each plant has its own ideal VPD level at which it grows fastest, healthiest and at the highest quality. For most crops, this range is between 0.8 kPa and 1.2 kPa.
By assuring the relative humidity levels are within optimal range, growers can help ensure their crops maximize their potential.
Air circulation completes climate control efforts
Greenhouses are dynamic environments. While we attempt to evenly control the climate throughout the entire space, the plants themselves constantly change their immediate surroundings.
As plants transpire, the area around them becomes humid. This is the boundary layer. When plant placement is dense, or when foliage grows too lush, it may trap the boundary layer. This causes pockets of humidity to form.
These pockets, or microclimates, are usually dealt with by increasing the dehumidification efforts. But dehumidifiers alone aren’t always able to reach these small air pockets, leading to overuse and unnecessary energy expenses.
This is where air circulation comes in. Properly designed circulation is meant to homogenize the climate in the space. It achieves this by effectively sending air in all directions, to all corners of the greenhouse. In this fashion, it quickly disperses the boundary layers, even inside the canopy.
By eliminating microclimates, the entire growing space experiences one uniform climate, which makes climate control much more effective. This helps increase rate of growth and quality of the crops, while decreasing unnecessary energy consumption.