Objective To determine the optimal application concentration of CaCl₂ for the management of autumn field Muskmelon production during seedling stage, and to provide theoretical reference for improving the stress resistance and strong seedling rate of Muskmelon seedlings.

Methods The main variety of sweet melon planted in the field, 'Xizhou Mi 17', was used as the test material. Five different concentrations of CaCl₂ treatments were set up to analyze the differences and correlations in growth and development, root morphology, and other indicators of Muskmelon seedlings.

Results  Spraying exogenous calcium significantly increased the plant height, stem thickness, leaf area, and root vitality of Muskmelon seedlings at different leaf stages within the concentration range of 0-5 mmol/L. Within the concentration range of 5-20 mmol/L, the plant height, stem thickness, leaf area, main root length, lateral root number, root surface area, root volume, root crossing number, and root branching number of each treatment showed an overall decreasing trend with the increase of calcium ion concentration; Stem thickness is significantly positively correlated with root vitality, main root length, plant height, and leaf area, and root biomass is also significantly positively correlated with plant biomass.

Conclusion Foliar spraying of 5 mmol/L CaCl₂ has a good promoting effect on the coordinated growth of aboveground and root systems in autumn Muskmelon seedlings.