A field experiment was conducted during two growing seasons to study the effect of foliar application of potassium dihydrogen orthophosphate (KH₂PO₄) at different concentrations; 0, 1000, 2000, 3000, 4000 ppm, and sowing date (15^th October, 1^st November and 15^th November) on the growth, fruit yield, and essential oil productivity of coriander (Coriandrum sativum L.). Among the three sowing dates tested, plants sown on 1^st November recorded the best results regarding all characteristics during both seasons, except for plant height during the second season only and stem diameter during both seasons which were significantly increased for the plants sown on 15^th October. Plants grown on 15^th October significantly surpassed those grown on 15^th November in most of the studied parameters. Foliar application of KH₂PO₄ fertilizer exhibited a significant effect on plant height, branch number/plant, stem diameter, umbel number/plant, fruit dry weight per plant and per fed, harvest index, essential oil percentage and essential oil yield per plant and per fed. The highest concentration of KH₂PO₄ (4000 ppm) showed the best results of all studied parameters comparing to the control and the other concentrations in both seasons. The best results were noticed in the plants grown on 1^st November and treated with potassium at 4000 ppm in all parameters except for plant height which achieved the best combination when plants were sown on 15^th October and treated with potassium at 4000 ppm.