Accurate measurement of spatial distribution of temperature and other micro-climatic parameters inside a greenhouse is important for their monitoring and control. To that end, suitable sensors in adequate number need to be appropriately distributed inside the greenhouse. Two new techniques, namely, Equal Temperature-Step (ETS) and Equal Segment-Area (ESA) techniques are proposed here for the selection of an optimal number of temperature sensors and their locations in a greenhouse with the objective of minimizing the Average Error (AVE), Root Mean Square Error (RMSE) and Maximum Temperature Error (MTE). These techniques were compared with TAE technique, reported earlier. Computational algorithms for the proposed techniques are also presented. Mathematical model of a typical temperature profile along the length of greenhouse has been developed and used for evaluation of the performance. The study shows that the minima of the three errors did not occur simultaneously for any number and locations of the sensors for TAE method. For ETS and ESA methods, the minima of all the three errors occured for the same number and locations of sensors and a smaller number of sensors needed to be used from error consideration. However, reduction in the errors with increase in the number of sensors was steeper for ETS technique as compared to ESA technique, thereby making ETS the best technique. This work can be readily adopted for the measurement of spatial distribution of any other parameter in a greenhouse.