To study the influence of low poly tunnel and planting time on the yield and economics of Muskmelon, an experiment were conducted in 2016-17 to 2017-18 at vegetable experimental farm, Nalanda College of Horticulture, Noorsarai, Bihar Agricultural University, Sabour (Bhagalpur). The treatments consisted of five date of sowing ., 5th December, 15th December, 25th December, 5th January and 15th January under open field as well as low plastic poly tunnel respectively. The farmer practice taken as a control in open field. Results were found to be significant for growth parameters and yield. The results clearly indicated that fruit yield/hectare ( q ), number of fruits/plant (), fruit diameter (), were recorded significantly higher when the date of sowing was 15th December under poly tunnel as compared to unprotected or open field. Environment is the aggregate of all external conditions which influence growth and development of plants. Temperature can be controlled and regulated under protected conditions and better growth of plants might be expected under low poly tunnel. Relative humidity reduces evaporation loss from plants which lead to optimum utilization of nutrients. It also maintains turgidity of cells which is useful in enzyme activity leading to a higher yield. However, under farmers field condition 15th February sowing recorded significantly maximum for fruit yield/hectare ( q), weight of fruit (), vine length ( cm ) and number of fruit /plant (). As per as net return is concerned, the significantly higher (Rs 1720075 per hectare) was found under low poly tunnel condition 15th December sowing overall other treatment. Therefore, it was evident from the above results that poly tunnel condition found to be the best for higher off season production of muskmelon and fetch higher return. | Yield and economics of muskmelon as influenced by low poly tunnel and planting time