The strawberry spider mite Tetranychus turkestani Ugarov & Nikolskii (Prostigmata: Tetranychidae) is an important pest on greenhouse cucumber. Therefore, understanding the effect of sublethal concentration of acaricides using demographic toxicological analysis is important for successful management of this pest. Laboratory studies were conducted to assess sublethal (LC₂₅) effects of Biomite^®, a natural based miticide, on the population growth and life-table parameters of T. turkestani. Three commonly greenhouse cucumber cultivars including Milad, Khasib and Puia were used in the study. Developmental times of T. turkestani immature stages were decreased on treated cultivars, while total life spans were significantly increased on treated cultivars when compared with the control groups. For Milad cultivar, adult pre-oviposition period (APOP) was significantly decreased when females were treated with LC₂₅ of Biomite^®. However, the total pre-oviposition period (TPOP) increased in the treated females. The intrinsic rates of increases (r) were higher in all the treated cultivars in comparison with control. The r values were 0.20, 0.21 and 0.18 day^-1 in the control group of Milad, Khasib and Puia cultivars which increased to 0.36, 0.38 and 0.37 day^-1 in the treated females, respectively. The age-stage survival rates of the female adults increased in the Biomite^® treated cultivars. The life expectancies of one-day-old female adults of T. turkestani were estimated to be 5.73, 6.54 and 6.14 days on the control group of Milad, Khasib and Puia and 8.96, 10.46 and 10.19 days on the Biomite^® treated cultivars, respectively. It could be concluded that sublethal concentrations of Biomite^® stimulated fecundity of females and as a result increased population development. However, further studies in greenhouses and in the field are required to confirm the results.