A superabsorbent hydrogel, capable of absorbing sixty times its volume in water, was synthesized by copolymerization of polyacrylamide and kappa carrageenan isolated from the red alga Hypnea musciformis. We assayed the potential of this gel to partially replace traditional germination and culturing substrates for lettuce Lactuca sativa of the Green forest variety. The gel was tested in combination with natural fibers (rice bran) and peat, in varying proportions, as germination and culturing substrates. Water retention in the substrate increased when greater concentrations of the gel were employed. During the seedbed stage there were no significant differences in foliar area or in the number of seeds that germinate upon addition of the gel between treatments. In the field stage, there were no significant differences in growth between plants germinated in gel compared to plants germinated in peat or bran-peat mixtures. Since our gel is much cheaper and has a great moisture reatining capacity 8 - Universidad Jorge Tadeo Lozano - Direccion de I nvestigacion Resultados de I nvestigacion - Facultad de Ciencias Naturales - 89 Agradecimientos Los autores agradecen al Centro de Investigaciones y Asesorias Agroindustriales (CIAA) de la Universidad Jorge Tadeo Lozano el prestamo de sus instalaciones para los ensayos de germinacion y cultivo. De igual manera manifiestan sus agradecimientos a la ingeniera Sandra Pulido por la disponibilidad del semillero del CIAA, al Ingeniero Cesar Salamanca por los ensayos de absorcion de agua y a la estudiante Luisa Yepez por su trabajo de campo. Los autores le agradecen tambien a Miguel Angel Rodriguez, profesor del Departamento de Ciencias Basicas, su asesoria en el analisis estadistico. than traditional substrates, we strongly recommend its use as a germination and culturing substrate for orchard greens.