A mathematical model was developed in order to predict quantities of CO2 and O2 gas exchange, transpiration, biomass production, food production and nutrient absorption by candidate crops in Closed Ecology Experiment Facilities (CEEF) in which material recycling in a controlled ecological life support system (CELSS) is to be made. This model includes effects of physical parameters such as light intensity, air temperature, humidity and atmospheric CO2 concentration on these processes and plant aging effect on these processes. Using results from experiments in which candidate crops were grown under controlled environment and data from literature, mathematical models for each crop was given physiological parameters. Then, changes in biomass and food accumulation, gas exchange and transpiration of each crop with time were calculated. It was shown that amount of these physiological processes as a whole crop community in CEEF can be stabilized by simultaneous cultivation of different age crops.