How can winter greenhouse lighting be managed?

Users that utilize greenhouses in the winter must have daylighting issues. 

Why is this, then? How are these issues to be resolved? 

1. The greenhouse's interior and outside temperatures varied by between 10 and 15 degrees Celsius. 

2. Based on observations of the sun's brightness, the amount of light entering the room is adequate to meet the sound field crop's photosynthetic total compensation point. 

3. If there is a significant temperature differential, opening the insulating curtain gradually over a period of time rather than all at once can help moderate the inside temperature fluctuations.