Temps and Humidity: A Guide

Tara | January 18, 2022
leaf close up
Temperature & Humidity

Temperature is an essential factor to consider when growing indoors as it can impact the plant’s growth and overall health. Maintaining optimal air temperature and humidity levels helps ensure adequate carbon dioxide (CO2) is available to the stomata, allowing for vigorous growth. If the temperature is excessively hot or cold, it can reduce the plant’s chemical and photosynthetic activity, leading to stunted growth and other issues.

Similarly, excessive humidity can suffocate the stomata, reducing the plant’s ability to collect the CO2 needed for growth. High humidity levels can also reduce the plant’s ability to transpire, affecting water movement from the roots to the leaf surface. This, in turn, can slow down growth, negatively affecting the plant’s health.

Moreover, temperature can affect the root system differently from the stem, leaf, and flower structures. If the water temperature is too high, the available oxygen to the root zone can be reduced, causing damage to the root system. This can negatively impact the plant’s ability to uptake nutrition and can lead to oxygen starvation, which is the primary cause of root rot in hydroponic systems.

Therefore, growers need to carefully monitor and control the temperature in the grow room to ensure the best possible environment for cannabis growth. A temperature range of 20-23°C during the day and 20-23°C at night is generally considered optimal. Maintaining appropriate temperature levels is essential for maximizing yields, potency, and overall crop quality.

What Temperature Should My Grow Room Be?

Recommended day temp is 26 – 28 °C

Recommended night temp is 20 – 23°C

Try to minimise the swing between night and day temperatures. Use a thermometer to record temps/swings. A thermostat is also a useful tool for controlling temps.

What Humidity Should I Maintain?

Clone – above 80%

Grow stage – 60%-80%

Bloom stage – 50%-60%

When humidity is too low, an Evaporative Cooler can increase humidity levels. When humidity is too high, consider extra ventilation or a dehumidifier. A hygrometer is a useful tool for measuring humidity.

How Much Ventilation is Necessary?

The purpose of ventilation is to maintain temps and humidity in the centre of the plant canopy. Generally, it is preferable to have too much ventilation than not enough. Replenishing the air in the room provides more CO2 for your plants.

Don’t Overlook Nutrient Solution Temperature

A crucial, yet often overlooked factor in hydroponic environmental control is the temperature of the nutrient solution.

Why Does Temperature Make a Difference?

The temperature of the nutrient solution impacts the amount of oxygen that can be transported to the roots. Cooler water is able to retain more oxygen, while warmer water retains less oxygen.

What is the Optimum Water Temperature Range?

The optimum water temperature range is 18-22°c. The ideal temperature is 20°c.

At 25°c water can hold 5ppm of oxygen. At 20°c water can hold 8ppm of oxygen.

Problems Resulting from Incorrect Water Temperature

When the nutrient solution is too warm, plants may begin to suffer from heat stress. Symptoms of heat stress include wilting and root diseases. Warmer water temperatures also provide the optimum environment for pathogens (damaging microorganisms, fungi, and bacteria) to multiply in the nutrient solution, on the plants roots and in the root zone. The beneficial microorganisms that keep pathogens in check can’t survive in the warmer water, allowing pathogens to multiply. Rotting roots caused by high water temps also feed the pathogens.

Cold nutrient solution problems don’t occur as often, especially in Australia’s relatively warm climate. However if the nutrient solution is too cold, it can stunt and slow plant growth.

Controlling the Nutrient Solution Temperature

We recommend the use of a water chiller during the warmer months. An effective water chiller can quickly chill 2 x 200L barrels of nutrient solution. A water chiller can also be used to regulate the temperature of multiple Turboklone stations.

We recommend the Hailea HC series water chillers. For more information, drop in for a chat or contact us anytime.

Share this article

Related Articles

Get 10% off your first order Subscribe to get code (check your junk folder!)
© Glandore Hydro All Rights Reserved
linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram