Industrial effluents are increasingly explored for reuse in agriculture; however, their concentration-dependent effects on crop growth and physiology remain inadequately understood. The present study examined the impacts of varying concentrations of fruit processing industry effluent on the growth and biochemical parameters of Arachis hypogaea L. (groundnut), along with physico-chemical investigations of the effluent. Seeds were sourced from a private agrocentre, and different effluent concentrations were used for irrigation. Growth and biochemical parameters were assessed at 7, 15, and 30 days after sowing (DAS). The results indicated that lower effluent concentrations, particularly 5%, significantly enhanced plant growth and biochemical attributes. At 30 DAS, plants treated with 5% effluent showed maximum shoot (37.5 cm) and root length (24.3 cm), as well as the highest fresh (23.73 mg g⁻¹) and dry weight (10.13 mg g⁻¹), whereas the lowest values for these parameters were recorded under 100% effluent treatment. Biochemical parameters showed a similar trend, with maximum chlorophyll a (3.144 mg g⁻¹ fresh weight), chlorophyll b (1.443 mg g⁻¹ fresh weight), total chlorophyll (4.587 mg g⁻¹ fresh weight), carotenoids (2.010 mg g⁻¹ fresh weight), protein (8.342 mg g⁻¹ fresh weight), and amino acids (2.843 mg g⁻¹ fresh weight) recorded in plants treated with 5% effluent at 30 days, whereas exposure to 100% effluent caused marked reductions in all biochemical constituents, indicating phytotoxic effects. Overall, the study demonstrated that diluted fruit processing industry effluent (up to 5%) can be utilized for irrigation and may serve as a liquid fertilizer, whereas untreated or highly concentrated effluent is toxic to Arachis hypogaea L.