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.
Recommended day temp is 26 – 28 °C
Recommended night temp is 20 – 23°C
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.
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.
A crucial, yet often overlooked factor in hydroponic environmental control is the temperature of the nutrient solution.
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.
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.
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.
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.