Winter has almost finished but each year same themes return. What reduction in light is caused by a (fixed) screen, what is the best greenhouse orientation etc. etc . Especially in winter it is important to realize a high quality and crop production. In this period, product prices are in general high, which makes precisely winter production so important.
Consequently in winter light is a limiting growth factor and available natural light has to be used as much as possible for the crop- production. In general in the winter this means 1 % more light is 0.8-1 % more production. In the 80's for normal glass it’s already determined that an east-west gutter direction is optimal in winter in terms of light interception by the cover. With the advent of diffuse glass, with or without coatings, condensation properties which can be influenced and possibly other greenhouse cover shapes the optimal with regard to the winter light properties has probably. The points mentioned above should make it possible to get an additional 10% more natural light in the greenhouse on the crop in the winter, but the road to this light gain is still uncertain, because gains at one point can cause a loss to the next. We hope to begin to answer these questions on short term.