The best time of day to water plants is in the evening or early morning. This is because water applied during the day, particularly at noon, will be most affected by evaporation by the sun's energy before it can soak into the soil. By watering during the evening or early morning, the water has a chance to seep into the soil to allow maximum availability to the roots of plants. 
        
             
        
        
        
The greenhouse effect is the trapping of a stars warmth in the lower atmosphere of a planet by gasses in the air trapping the energy. This is similar to what actual greenhouses do, where they trap the warmth and humidity of the air inside it so plants can flourish. Farm animals produce a huge amount of the greenhouse gasses required for our planet to trap the suns warmth.