Earth based Bioregenerative Life Supporting Systems (BLSS) are subject to 4 main physical factors: gravity, light, temperature and electrical environment. The first 3 are obvious to everyone, the Electrical Environment (EE) is not under the majority of prevailing conditions perceived directly by our senses. The EE is one of the important physical factors directly influencing some plants and in a less obvious way also the majority of plants. There are only two long range forces in nature: the electromagnetic and the gravitational forces. Gravity is very much weaker than the electromagnetic forces FG/FEL=10(-38), where FG is the gravitational Force and FEL are the electromagnetic Forces. The atmospheric electric field prevails all the time over the entire Earth with a mean intensity of 130 V/m. It is therefore a potent factor which may be used by some plants exposed throughout their entire life time to the atmospheric electric field. What effect should the normal atmospheric electric field have on plants? All living plants are good electrical conductors for electrostatic fields. The plants distort the normally vertical field lines, which have to be perpendicular to the plant tissue everywhere in order to avoid the extraction of energy from the field. The meristems concentrate the field lines, thus the electrically charged nutrients are supplied to the growing parts of the plant exposed to the field. This results in electrotropism in some plants. It is very well known that plants do have adaptive capabilities as compared to animals, it is important for their survival, because they cannot run away from trouble. It is found by careful observations of the behaviour of different plants that some plants do respond to the presence of the atmospheric electric field while other plants exposed to the same environment are indifferent to the atmospheric electric field. The plants growing in the Biosphere II were shielded by the metal structure of the Biosphere II. Because these plants which do make use of the atmospheric electric field are also to be found in the Biosphere II and must be deprived of this natural atmospheric electric field and in consequence of some of their natural nutrients. I have experimental evidence that at least some plants do respond to the atmospheric electric field. This effect is the most likely cause of the oxygen depletion and of the carbon dioxide accumulation in Biosphere II. Under the micro gravity encountered in space habitats the restoration of electric fields is even more important for plant growth than it is on the Earth.