Abstract: A method of developing and maturing somatic embryos in a growth environment, which method comprises manipulating the water availability of the growth environment using a physical means of control. The invention also provides a growth environment for maturing somatic embryos, wherein the water potential of the embryogenic tissue is manipulated to optimize somatic embryo development and maturation. The invention further relates to a somatic embryo matured by the method of the invention. In the invention, a physical means of control is used to affect the water potential of the embryogenic tissue and developing somatic embryos growth medium, rather than a chemical means such as the introduction of PEG, to stimulate the maturation of the embryos. The physical means may be operated, for example, by separating the somatic embryos from the growth medium by a porous support, or by introducing a gelling agent (e.g. gellan gum) into the growth medium in larger than normal quantities.