What is the ideal grow room temperature?

The recommended day temperature with the cultivation of your “favourite plant” lies between 25 and 28 deg C. With higher temperatures the growth will slow down and the yield and quality will decrease (many growers experience this during summer). In the dark, other chemical reactions occur in the plant than in daytime. A lower temperature suits them best. The recommended night temperature lies between 15 and 20 deg C. With temperatures lower than 15 deg C the growth is obstructed, lower than 10 deg C the growth stagnates and lower than 5 deg C will damage the plant. The most ideal situation would be a grow room with both heating and airconditioning. 

The roots are especially sensitive to low temperatures. The absorption of nutrients through the roots is an active process. This means that the root needs energy to absorb the nutrients, but also to be able to select these nutrients. The root can, to a certain point, choose which and how much nutrient it absorbs. This process can be seriously disturbed with too low a temperature, because then there is insufficient energy available for this process. Therefore you have to make sure that when watering the plants the water is approximately 23 deg C. With cultivation on rockwool the nutrient solution temperature is held constant with the use of a special twin glass sleeved aquarium heater that has a built-in thermostat.