Soil is one of the essential components required for plants to grow. Soil amendment becomes a necessity for poor and marginal lands to be brought into agricultural applications. The methods involving inorganic fertilizers are very common but not sustainable due to environmental impacts. A sustainable amendment in the form of biochar for soil is gaining popularity with time because of its carbon sequestration ability, high resident time in soil, and ability to enhance soil quality with minimal negative impact. In the current study, biochar made from Napier grass grown with saline water as a tool for soil amendment was explored for sandy soil, which has lower nutrient content and water holding capacity. Under optimized preparation, biochar was produced from the Napier grass grown with saline and sweet water. The effect of this biochar on the pH, electrical conductivity, water holding capacity, porosity, and cationic exchange capacity on the desert soil was studied to check its suitability for soil amendment and the results were compared with commercial potted soil available in the market. The results indicated a significant improvement in the physical properties of the sandy soil and were comparable to the commercial potted soil. Effect of the biochar on plant growth was studied in a pot experiment conducted for 90 days in which cow pea plant was grown in pots containing desert soil and soil amended with 10% and 20%(W/W) biochar. Analysis of variance (ANOVA) was used to identify significant differences in plant growth between the different mediums used for growth. Linear regression was also used to evaluate the predictive power of the variables identified by ANOVA.