Determining the Appropriate Surface Area of Greenhouses with Economic Indicators Case Study: Tehran Province

The increase in the area under greenhouse cultivation in Tehran Province is important for the increase in production and for its substantial social importance due to the preservation of agricultural land, especially small farms. In addition, the increase in the number of greenhouses producing summer crops in this province attracts idle capital to the agriculture sector thereby creating jobs. The present research used stratified cluster sampling for selecting the counties of interest having the largest areas under greenhouse cultivation of summer crops in Tehran Province in order to select the producers in each greenhouse size range (taking into consideration the number of producers in it) via random sampling in which a table of random numbers was employed. Fifty-five greenhouses were selected in the province, 22 greenhouses producing only cucumbers, 15 greenhouses producing cucumbers and tomatoes, and 18 greenhouses producing cucumbers and bell peppers. The results of the cost-benefit analysis (CBA) showed that production of greenhouse summer crops was economically justified for greenhouses larger than 3000 m2 in surface area. However, the trend in the profitability of activities was a rising one for greenhouse surface areas of up to 4500 m2 beyond which a falling trend was observed. Finally, it was suggested that the Jihad Agricultural Organization of Tehran Province refuse to issue an establishment license for the production of greenhouse summer crops in areas lower than 1500 square meters and provide the necessary incentives for the production of greenhouse summer crops in Tehran, in areas between 5000 to 7500 square meters.