Worldwide food creation is seriously hampered by drought. Biochar and potassium silicate are essential for how crops use their energy, whether under favorable or adverse conditions. They may also make plants more drought tolerant. Ajwain (Trachyspermum ammi L) is a medicinal and aromatic plant that is cultivated mainly for its seed, herb, and volatile oil. This present study was carried out to evaluate the effects of biochar and foliar application of potassium silicate K2SiO3 under irrigation intervals (3, 4, and 5 days) on growth, fruits yield, essential oil, and its main components as well as chemical constituents of Ajwain in filed experiments conducted at the Experimental Farm of East of Malawi, El-Minia Governorate, Egypt during the two seasons of 2020/2021 and 2021/2022. A split plot design in four replications was used. Three irrigation intervals in main plot biochar and potassium silicate treatments and/or in sub plot. Results showed that irrigation every 3 and 4 days produced the highest yield with higher quality parameters. While irrigation every 5 days gave highly significant positive values of water use efficiency. Biochar + sprays of K-silicate produced the highest fruit yield. Irrigation every 3 and 4 days combined with biochar + foliar spray of K-silicate achieved the highest values of fruit yield and its components. These results show that biochar + K-silicate treatment can increase water use efficiency and produce high fruit yield.