Greenhouses

In greenhouses construction is very simple:
In the summer greenhouse's too hot air will be led
to the ground with pipes and the same but cooler
air will come back to the greenhouse.

You need not ventilation, less irrigation, less energy
and added carbon dioxide stays better in the greenhouse.
In the winter air circulates in same pipes and bring back
the same warm to the greenhouse.

Lights are perhaps very rapidly beated blue and red leds
because of economize electricity.

Production of food must be more economical.
TH