Greenhouse Temperature

how to meet the temperatuer in the greenhouse for crops growing

The indoor air design temperature is usually set by the greenhouse construction company for greenhouse design requirements, based on the type, variety, growth period (or growth period) of the crops to be planted in the greenhouse, and the cultivation season (the time of the entire crop cycle in a year) ) derived. For example, tomatoes have different requirements for temperature at different growth stages: the suitable temperature for seed germination is 25~30°C, and 28°C is the optimal temperature. Most varieties have low germination rates above 35°C, and it is difficult to germinate above 40°C; the seedling stage has different temperature requirements. It has strong adaptability. The suitable temperature is 23~28℃ during the day. If the temperature is too high, the seedlings will easily grow. The flowering period requires a higher and strict temperature. Generally, 25~28℃ is suitable. If it is higher than 33℃, it will cause flower drop. The fruiting period is generally The day temperature is 25~28°C. Fruit coloring has strict temperature requirements. 19~24°C is beneficial to the formation of lycopene, while temperatures above 30°C are detrimental to coloring.

Although the maximum cooling load must be estimated during ventilation design, there is no need to determine the design value according to the lower limit for the suitable temperature range of cultivated tomatoes of 25 to 28°C, because the values of other parameters are considered to meet the minimum requirement during calculation. Unfavorable conditions, so the cooling load estimated based on the upper limit of 28°C can already meet the temperature requirements of crops during the entire growth period. However, considering the economics of equipment configuration and greenhouse engineering construction, the upper limit of suitable temperature is not The only option. According to cultivation practice, as long as the night temperature can be lowered so that the average temperature of the day is controlled at 21°C, the temperature requirements of tomatoes can be met. For example, the maximum daily temperature control target can be 30~32°C, as long as the night temperature can be lowered so that The average temperature of the day is controlled at 21°C, which can still meet the temperature requirements of tomatoes. Therefore, for areas with large temperature differences between day and night and good lighting conditions, the indoor air design temperature can be higher than the upper limit of suitable temperature, but it should not exceed the maximum temperature limit.