This paper introduces a longitudinal investigation about the aspects of the Innovative Educational Projccts in Andalusia, in the Environmental Education field. The analyzed period goes from the mid-eighties till the present time. The aim is to study the process of school construction of cross-curricular tapies, with a special interest to the teacher decisions. The facts show that, on the way from the written project till its practical development, there are a number of restrictions and adaptations which end up isolating the innovative experiments in exceptional and specific curricular times and places, and making inactive their own capacity to produce a complete educational change in the school and even in the community.