Transplant experiments are a useful tool both for determining species’ ranges and understanding their cause, yet such experiments have seldom been performed in areas where plants reach extremely high elevations. We examined the position of the upper elevational limits of vascular plants in E Ladakh, India, by transplanting individuals of 14 subnival species from 5800–5850 m elevation to a control site at the same elevation, as well as to edaphically suitable sites at 5960 m (subnival belt with sparse plant cover), to 6030 m (the highest elevation reached by vascular plants in the area) and to 6160 m elevation (no vascular plants observed). Two years later, transplants of 13 species survived at the control elevation, whereas 5 species survived at 5960 m, 2 species (Waldheimia tridactylites, Poa attenuata) at 6030 m, and none at 6160 m. The highest elevation at which transplanted flowering plants survived corresponds well to the observed elevational limit. Soil temperature data at the sites suggest that the growing season, defined as the period with mean daily soil temperature above zero, lasted nearly 3 months at 5960 m, ca 1.5 month at 6030 m, but <3 weeks at 6160 m, moreover interrupted at the highest elevation by several days with temperatures remaining below zero. The experiment confirmed the observed sharp limit of vegetation, set not by any physical barrier per se (e.g. not by the top of the massif), but instead by physiological constraints of the species. The result provides support for the assumptions of mid-domain effect models that domain limits are defined by shared organismal adaptations in relation to environmental gradients, in this case tolerance to freezing temperature.