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Maintaining Optimal Growth in Cold Conditions

With winter fast approaching, the colder temperatures can start to have a major impact on your plant’s growth and development.

During the day (lights on period), the optimum temperature for growth is between 25°C – 28°C and during the night (lights off) the optimum temperature range is 18°C – 22°C, with a relative humidity (RH) of 55 – 60%. When the ambient air temperature is too high or too low, or the humidity is too high, a plant will minimise the chemical processes that take place in order for it to grow. Ideally, you want to maintain climate conditions as close to this as possible, so what’s the best way to achieve this?

Airflow is your key to temperature & humidity control. A well balanced ventilation system will act as a self regulating climate control and continually provide plants with fresh air. The level of airflow or ventilation that is necessary will be determined by a few key factors;

  • Outside ambient air temperature (the air being drawn into the room)
  • The amount of lighting in the room (lights generate a certain amount of heat)
  • Relative humidity within the room (too much humidity will affect plant growth)

Lights are a source of heat within the room. The amount and intensity of lights will be a key factor in determining the amount of ventilation required. Exhausting excessive heat out of the room is a must, however its all in relation to the temperature of the air being drawn in to replace the exhausted air.

This is where outside ambient air temperature comes into play. As a general rule, the more ventilation the better. However, if it was 4°C outside, you wouldn’t want to be drawing large amounts of this cold air into the room as it would quite rapidly drop the ambient temperature within the room and fall below the optimum range of 25°C – 28°C. But ventilation is absolutely necessary, so how do you find a balance?

One method of combating this issue is utilise an advanced ventilation controller such as the SMSCOM Hybrid Controller. The Hybrid Controller uses software controlled temperature sensing technology combined with a mechanical system for controlling fan speed. It is designed to maintain a constant temperature inside your room whilst keeping airflow under control at all times. By controlling the speed at which your fans are spinning, you effectively control the amount of air being ventilated, which in-turn affects the overall ambient temperature.

Another method for climate control is the introduction of a CO2 gas burner into your room, which can assist in 2 ways:

  • It is an extra source of heat
  • It is a great source of CO2

With the increase of available CO2 from the gas burner, it reduces the plants dependency on fresh air for CO2 and subsequently reduces the need to ventilate the room so frequently. This combination means that the outside colder temperatures are negated to a certain degree, allowing you to maintain more consistent conditions within the room.

However, healthy plants that are growing well in optimal conditions will naturally release moisture into their surrounding atmosphere through a process called transpiration. This process effectively increases the overall humidity within the room, which can then start to have a negative impact on growth. Put simply, plants don’t like humidity – however, they create humidity as part of their natural growing process. Coming back around full-circle, ventilation is the most common method used for controlling humidity.

Finding the correct balance of ventilation and fresh air, temperature regulation and humidity control can be tricky, however we are always here to help. If you need assistance in determining the best solution for your particular needs please give us a call or visit us in store and we can go over this in greater detail.