Timely harvesting is an important prerequisite for quality standardization in the traditional Chinese medicine industry. To determine the harvest time of Artemisia argyi and clarify the influence of meteorological factors (MFs) on the harvest time, we selected two excellent germplasm resources, namely, “Nanyang 1” (NY) and Luoyang Artemisia argyi (LY), as examples. We examined the changes in yield, quality, and related traits on 11 sampling dates (SDs) after the six true-leaf stage. Additionally, we analyzed the relationship between eight MFs on different SDs and yield, as well as quality indices. The results show that the SDs and MFs have a significant impact on yield and quality. The dynamic changes in growth traits and dry matter accumulation characteristics of NY and LY were basically consistent. From 75 to 90 d, Artemisia argyi was in the middle and late stages of the transition from vegetative growth to reproductive growth, during which the amount of dry matter accumulation stabilized. The leaves are the most representative medicinal part, with the comprehensive values of the LY leaf yield and main medicinal ingredient contents reaching their maximum at 75 d; the comprehensive values of the NY leaf yield and main volatile ingredient contents reached their maximum at 75 d, while the comprehensive value of the flavonoid and phenolic acid contents reached their maximum at 90 d. Therefore, LY is suitable for harvesting at 75 d, while NY can be harvested at either 75 or 90 d, depending on the harvest goals. In addition, the mean daily minimum temperature (MDMNT), effective accumulated temperature above 10 °C (≥10 °C EAT), and mean temperature daily range (MTDR) were found to be key MFs affecting harvest time. The dry matter accumulation of the roots and stems was significantly positively correlated with the MDMNT (p < 0.01). The dry matter accumulation of the leaves was significantly positively correlated with ≥10 °C EAT (p < 0.05). The total volatile oil content was significantly positively correlated with the MTDR (p < 0.05). These show that meteorological factors affect the harvest time in production practice. This study provides scientific support for determining the harvest time and managing the cultivation of Artemisia argyi.
