Studies developed in a scholar context report a restorative effect of nature on human beings, specifically in terms of the psychological recovery from attention fatigue and restored mental resources that were previously spent in activities that require attention. Studies usually compare the performance of children in schools with or without access to green spaces. In this study, the effect of introducing greenery into the classroom context was compared across time. The experiment was developed in two primary schools with pupils in different socioeconomic contexts, at three moments: before introducing an artificial green wall into the classroom, one month later, and one month after the introduction of vegetable pots. Results showed a significant increase in sustained and selective attention, and work memory between the experimental and the control group, notably in the third moment when vegetable pots were introduced. In the second moment (green walls), only the work memory (tested with the inversed number) showed a significant effect. Theoretical and practical implications are discussed in terms of nature’s role both in terms of natural and artificial elements and the cumulative effect of direct interaction with natural elements.