Two field experiments were carried out during the winter seasons of  2011/2012 and 2012/ 2013 at The Experimental Farm of The Faculty of Environmental Agricultural Sciences, El-Arish, Suez Canal University, North Sinai Governorate, Egypt. The experiment aimed to study the effect of spraying tomato plants (Solanum lycopersicum) GS 12 cv.  with different calcium sources (calcium chloride, calcium carbonate and calcium chelate as well as without calcium) at different times of application, viz, T₁: spraying one time at full blooming, T₂: spraying one time after 15 days from T₁, and T₃: spraying two times at T₁ + T₂ on marketable yield, unmarketable yield (expressed as fruits infected by blossom end rot (BER)), and quality of fruits after 10 days of beginning the storage period. Plants were grown under low tunnels. Spraying tomato plants with Ca⁺ as CaCl₂ or CaCO₃ and other Ca sources increased the marketable yield/ fed. , and also increased fruit shelf life period expressed as decreasing in fruit weight loss and increasing fruit firmness. Foliar application of CaCl₂ recorded the lowest values of lycopene contents in both seasons. Time of calcium application did not reflect any significant effect on both marketable and nonmarketable yield as well as marketability (%) and BER incidence (%), and almost pH and TSS values. Application of T3 increased the fruit contents of vitamin C (V.C), while using T2 decreased the content of lycopene. All interaction treatments with control (without application of calcium) decreased marketable yield, marketability (%), but it increased unmarketable yield, BER incidence (%), fruit weight loss and TSS in the 2^nd season. Therfore, spraying tomato plants grown under low tunnels in calcareous soil with Ca in different sources had positive effects on both marketable yield and blossom-end rot incidence, total yield, marketability%, BER% and on fruit quality after 10 days of storage period compared to control.