How do you know plants suitable for soil temperature?

Different plants to survive in different season, but in today's agricultural technology development, whether in what season we can eat different fruits and vegetables, everyone will say that is because they grow in the greenhouse, but the temperature in greenhouses plants need is how many? How do you know the specific heat temperature and soil temperature? Everyone will say, it is good to put a soil thermometer inside, but often workers would know in greenhouse, the temperature in the greenhouse is different from morning till night, if you want to in the greenhouse crop growth is very good, always paid close attention to the change of temperature, but how to focus on? Should people keep on the thermometer? This is too unrealistic, below, to everyone said one bimetallic thermometer, it is the electric contact bimetallic thermometer, it is an automatic alarm thermometer, has brought people great convenience. It on the basis of the original instrument installation of electric contact structure, using the drive contact changes when temperature changes, when the temperature reached or exceed the set value, when touch point contact with the upper and lower limits or disconnected at the same time, make the circuit of relay action, close contact signal, to control and alarm automatically. It a mercury-free harm, easy reading, solid and shock resistant, waterproof, anti-corrosion, vibration resistance and other characteristics, intuitive and convenient alternative to other forms of thermometer table, can replace industrial glass mercury thermometer, can be applied to most of the corrosive medium, gas measurement. In addition, it has many kinds of structure forms, can meet different requirements. Can say electric contact bimetallic thermometer to grow crops in the greenhouse of people has brought great convenience, can need not pay attention to the temperature of the thermometer can always understand the relative changes.