The Pyongyang Dental Hygiene Products Factory built two solar greenhouses on the roof of a workshop building to produce vegetables.

At those greenhouses, based on the soilless cultivation method by nutritive liquid and the hydroponic cultivation technology, all operation processes such as the supply of nutritive liquid and the control of temperature and humidity are put on an integrated control system.

Several layers of shelves were installed on the floors and walls of the greenhouses to expand the cultivation area and ensure high density. And water tanks of tens of cubic meters were arranged to breed catfish, tilapia and other fishes. The water for fish farming is recycled.

Ri Yong Suk, manager of the factory, said that the produced vegetables and fishes are used for dietary life of the employees.