The present study was conducted to evaluate the effects of foliar application of nano and bulk calcium chloride and calcium carbonate on the morphophysiological responses of scented geranium (Pelargonium graveolens L.) under water deficit stress conditions. The experiment was carried out as a factorial experiment in a completely randomized design with four replications. The first factor was irrigation levels at two levels: control (80% available water) and severe stress (20% available water). The second factor was calcium chloride and calcium carbonate in both bulk and nano forms, each applied at concentrations of 5, 10, and 15 mM, along with a control treatment (0 mM). The analysis of variance showed that the effects of irrigation stress, calcium levels, and the interaction between calcium and irrigation were significant (p ≤ 0.01) for most evaluated traits. The application of 10 mM nano-calcium carbonate under 80% available water increased stem strength by 49.5% compared to the control. Foliar spraying with 15 mM nano-calcium carbonate under 20% available water increased stem strength by 125% compared to the unsprayed control under the same irrigation condition. The application of 15 mM nano-calcium carbonate under control and stress treatments improved the stress resistance index by 40.3% and 50.6%, respectively. Additionally, the foliar application of 15 mM nano-calcium carbonate and nano-calcium chloride under 80% and 20% available water increased plant height by 31% and 45.7%, respectively, compared to the control. The best treatment for enhancing drought tolerance in scented geranium was identified as 15 mM nano-calcium carbonate.