Rising world population and higher per capita incomes anticipate increased demands for agricultural produces by the mid-21st century. As a result, issues arising from conventional agriculture could be tackled by growing nutrient efficient plants and effective agricultural practices. Greenhouse horticulture, is a sustainable alternative to maximises resource use for vegetable production. Cucumber (Cucumis sativus cv. Lebanese and Continental), a widely grown vegetable is primarily cultivated in greenhouses. Therefore, greenhouse experiment was conducted at three different electrical conductivity levels (EC 1.0, 2.5 and EC 3.5) to evaluate its effect on productivity and quality of cucumbers. Statistical analysis performed on the collected data illustrated no significant effect on productivity and photosynthesis rate of cucumbers however, chlorophyll fluorescence established an inverse relationship with electron transport rate showing comparable differences between EC 1.0, EC 2.5, and EC 3.5. To obtain response of potassium transporter genes at different EC levels relative expression analysis on cucumber leaves and fruits revealed interesting participation of genes like KEA3, KUP5, KEA5, KEA4, HAK5, KUP11, KAT3 affecting overall morphology of crop. Post-harvest results revealed highest percentage of weight loss in EC 1.0 of Lebanese and Continental at 2°C and 7°C. Metabolomics approach at different EC levels including carbohydrates, sugars and amino acids will participate in improving the fruit quality of cucumber by establishing strong link with physiological parameters and potassium transporter genes. These results can be taken as recommendations for better quality and yield enhancement by using low fertigation levels to achieve more resource-sustainable and profitable cucumber production in greenhouses.