The purpose of this study was to evaluate the aspects of medium term conservation under slow growth conditions of two rare plant species from Caryophyllaceae family: Gypsophila petraea (Baumg.) Rchb. and Dianthus callizonus Schott et Kotschy. Different methods like reducing carbon source, reducing mineral concentration and temperatures (25°C and 10°C) were tested. The evaluated parameters were represented by the healthy shoots and rhizogenesis. The presence of hiperhidricity was observed. To check the genetic stability of the shoots maintained under slow growth conditions, the biochemical analysis were performed after 6 months. The physical factors (lack of nutrients and temperature) changed the enzymatic spectra, but the biochemical analysis did not show differences between the clones cultured on the same media variant. The 10°C and the reducing of micro- and macronutrients at 1/4 for G. petraea and at 1/10 for D. callizonus allowed the conservation in optimal parameters for more than 12 months.