Abstract: The invention relates to a method to increase growth or differentiation in vitro in a cell or tissue culture comprising culturing said cell(s) or tissue and applying pulsed radiofrequency (PRF) to said cell or tissue. In said method the cells or tissue are derived from a plant or an animal (including human) and preferably the cells are undifferentiated cells. Also part of the invention is a method as described herein wherein the cells or tissue are derived from a plant and in which differentiation implies the outgrowth of roots and/or shoots or of somatic embryos. The invention further comprises the use of PRF for increasing the growth or differentiation in in vitro cell or tissue culture. The invention also comprises a cell or tissue culture treated according to a method according to the invention. Preferably such a cell or tissue culture is derived from a plant. Then, in yet another embodiment, the invention is directed to a plant grown from such a cell or tissue culture.