Providing a proper moisture condition is critical for successful cutting propagation. However, information on the precise moisture level needed for ensuring survival and rooting of cuttings is not quantitatively understood. This study was conducted to investigate the optimal substrate moisture content for enhancing the survival and rooting rates of Lavandula angustifolia for successful cutting propagation. Apical cuttings of L. angustifolia were obtained from Korea University Farm and were stored in a chamber at 15°C for 24 hours before sticking for the cutting propagation. Nine cuttings were stuck in a modified container filled with a propagation mix (Sunshine Mix #5, Sun Gro Horticulture, USA) with a sub-surface irrigation system with three sub-replicates and four blocks. Four irrigation threshold levels, −1.0, −2.5, −5.0, and −10.0 kPa, were provided through an FDR soil moisture sensor (EC-5, Meter Group) based automated irrigation system over six weeks. The volumetric water contents for each threshold level were determined at 0.62, 0.48, 0.35, and 0.26 m3･m-3 for −1.0, −2.5, −5.0, and −10.0 kPa, respectively, using moisture retention curve analysis of the substrates. At the final harvest, cuttings grown at −2.5 kPa showed the highest survival rate (83.3%), while cuttings grown at −10.0 kPa had mortality higher than 50%. Cuttings grown in −1.0 and −2.5 kPa (relatively wet conditions) displayed a relatively higher rooting percentage (53.0 and 47.2%, respectively) while those grown in −10.0 kPa showed the lowest rooting percentage (< 10%), suggesting wet substrate condition should be required to secure the survival and rooting rates of L. angustifolia cuttings. As time progressed, the number of adventitious roots and root length of the rooted cuttings increased, as well as their fresh and dry weights, regardless of irrigation thresholds. However, the number of leaves, shoot height, and biomass of all cuttings except for the −10.0 kPa treatment showed similar growth among the treatments until four weeks after sticking, while it was observed that the number of leaves, shoot height, shoot fresh weight, and shoot dry weight increased as the substrate moisture threshold level increased (p = 0.004, 0.016, 0.018, and 0.010, respectively) at the final harvest. These results suggest that cuttings of L. angustifolia required around four weeks to establish their adventitious root system, then accelerating their leaf and shoot growth further. Overall, −1.0 and −2.5 kPa irrigation threshold levels provided the optimal substrate moisture content for securing high survival and rooting rates of L. angustifolia, and at least −5.0 kPa is needed to emerge roots for surviving.