The study looked at how adding a substance called poly‐γ‐glutamic acid (γ‐PGA) to sandy soil affects its ability to hold water. Different amounts of γ‐PGA were tested, and it was found that using 1.2% of γ‐PGA was the most effective in increasing the soil's water retention capacity. This amount helped to improve the soil's ability to hold water without needing more γ‐PGA. The study also showed that the effect of γ‐PGA on soil water retention depended on the amount used and the number of wetting‐drying cycles the soil went through. Overall, adding 1.2% of γ‐PGA to sandy soil can be a good way to improve its water holding capacity.