Why and How to Control Temperature and Humidity in Your Grow Room?

Most novice growers have a handle on controlling a room’s temperature. Many may even know a thing or two about air circulation. However, novices often tend to struggle when it comes to maintaining the ideal relative humidity (RH) level in their grow room. For instance, did you know that humidity changes when you turn your grow room lights on and off? Sadly, many growers fail to pay attention to humidity until they encounter diseases such as bud rot or powdery mildew.

RH is the percentage of how much moisture is in the air versus the amount the air is capable of holding. RH and temperature have an inverse relationship. This means the RH in a room increases as temperature decreases, and vice versa.As for how humidity affects plants, remember, your marijuana crop respires CO2 from the environment through their leaves. During this process, they lose some of the water retained in their foliage.

Temperature and How It Relates to Humidity

Temperature and relative humidity are closely related to each other.

Temperature and Humidity Monitor, humidity is measuring how much water is “being held” in the air compared to the maximum amount of water that can be held at that temperature.Warm air can “hold onto” more water than cool air. Plants will tend to thrive at different relative humidities depending on the temperature of the air. Once the air becomes too saturated with water, it will tend to form dew or films of water over leaves, which leads to mold.

For those interested in learning more about the science behind this, there is a term used by greenhouse growers known at VPD, or Vapour Pressure Deficit, that roughly measures the temperature and relative humidity.

According to Wikipedia: “the ideal range for VPD in a greenhouse is from 0.45 kPa to 1.25 kPa, ideally sitting at around 0.85 kPa. As a general rule, most plants grow well at VPDs of between 0.8 to 0.95 kPa.”

When growing plants, temperature is just as important as the Relative Humidity (RH) of the air, if not even more so! You need to control both temperature and RH at the same time to get the best results when growing cannabis.

If the air is too hot and dry (high VPD), plants will tend to have stretched growth.
If the air is too cool and humid (low VPD), plants are more prone to problems with mold or fungus.

Regulating Temperature
The temperature in a grow space has an impact on the metabolic rates of the plant. The porous openings on the plant determine the intake of C02, heat, and light. Simply put, stomata are an inbuilt AC unit for plants. As the stomata open and produce water vapor, they transpire and remove freshwater from the roots up.

That said, when the temperature in the environment is low, this might slow down the plant processes, and this might hurt their overall growth. However, when the climate is warmer than usual, these systems work harder, and the stomata might close up. If the stomata close up, the water and nutrient delivery decreases and the plant fails to cool down as required.

You can regulate the temperature by manipulating for critical factors. They include:

The light – perhaps the most significant impact on the garden temperature relates to the type of light you are using, and the amount of heat it produces. Different grow lights will provide varying levels of heat and signatures. All these also depend on the size of your space, which in turn affects the room temperature. Incandescent lights such as metal halides and compact fluorescent lamps can produce lots of heat in small areas. That said, even some LED bulb brands can also produce heat.

Airflow – controlling the flow of air is an efficient technique for regulating the flow of hot and cold air in a grow room. The flow of air is vital in ventilation, especially in regard to the elimination of bad quality air from the grow room. More so, airflow is also crucial for canopy plants, which require top-notch ventilation and air quality.

Regulating Humidity
Humidity is the measure of water vapor in the air. There are four things you can use to help control it.

Dehumidifiers: Dehumidifiers remove moisture from the air. These units are used much more frequently in indoor grow spaces because plants in a confined space tend to create moisture, and the space will usually feel warm and humid.

Humidifiers: A humidifier can produce a constant flow of water vapor for an indoor garden. They use cool water to create a mist that disperses throughout the space and increases moisture levels. Here we recommend Eco Farm Humidifiers for you which we have already tested and found them in our top list.

Airflow: As with regulating temperature, regulating airflow will allow you to move moisture in and out of your grow space and control humidity. Simply opening up a grow space, i.e., opening the door to your grow room or tent, can bring down the humidity level.

Water: In the absence of a humidifier, you can mist plants with a spray bottle to create extra moisture.

ECO FARM Hydroponics 8L Capacity Air Humidifier Grow Room Tent

Indoor Household air Humidifier growing Room Tent Diffuser

Increases humidity in dry living spaces and grow room.

-Removes unpleasant odour and other smell.

-Removes dust and indoor air pollution.

-Disinfects and deodorizes indoor air. -Creates clean,hygienic and bacteria-free air.

-Place: Applicable for room size: 30m2.

-Working time: 14-28 hours.

-Caution: Better use clean water.

-Better switch off when power off.

-Waterless automatic protection.

-Mist-out mouth rotatable at 360°C.

-Chrome decorated switch for Mist Adjustment, Time setting and Night Light.

-Removable water tank with a wide mouth for easy filling.

-Low noise.

Pure Enrichment MistAire Ultrasonic Cool Mist Humidifier

• ULTRASONIC COOL MIST TECHNOLOGY: Safely moisturizes the air for up to 16 hours of continuous operation so you can breathe easy and get more restful sleep | High and low speed settings make it easy to adjust mist direction and speed to fit your comfort level
• 1.5-LITER WATER TANK: Provides ideal coverage for bedrooms, offices, and other medium-sized rooms
• OPTIONAL NIGHT LIGHT: Offers soothing glow for maximum relaxation
• AUTOMATIC SHUT-OFF: Turns humidifier off when water level is low or the water tank is removed
• WHAT YOU GET: Humidifier, AC power adapter, disk cleaning brush, user manual, industry-leading 2 Year Warranty, caring customer support 7 days a week, and the peace of mind that comes from a trusted brand with millions of customers worldwide.

Overall

Unfortunately, temperature and humidity control can only be as good as you are informed as a grower. You have to learn about the correct principles and methods behind growing specific plants. This way, you can give the plants an ideal environment to grow and survive, thus improve the result of your yield.

Broadly speaking, most plants perform best at 77°F (25.9°C), while some prefer the temperature to be at an average of (81-86°F). Using an informed approach is your best bet at achieving the best grow room results.

Also in Indoor Growing Guides