Nutrients’ distribution during fertigation of a felt-based living wall

The lack of space in cities has favoured the development of vertical gardens in indoor and outdoor environments. For an adequate development and appearance of the plants in these living walls, it is necessary to provide nutrients (usually by means of fertigation). One of the main limitations is the difficulty in obtaining a uniform distribution of nutrients, especially in felt systems. The objective of this research was to identify whether the distribution of nutrients (particularly iron and phosphorous) applied by fertigation in a felt living wall depended on the species used and the location of the plants in height. Three modules of a Fytotextile^® felt-based living wall were used, each module containing three columns of different species: Soleirolia soleirolii, Philodendron hederaceum, and Nephrolepis exaltata. Fertigation was applied using a Hoagland–Arnon solution for 4 months. Measurements of leaf area, normalised difference vegetation index (NDVI), chlorophyll meter readings (CMR), fresh and dry weight, and P and Fe concentration were carried out for each of the plants. Comparing variables within the same species at different heights showed no significant differences in the variables. This means that the distribution of nutrients along the living wall (especially in height) was uniform. It is important to note that these results could vary for other types of living walls or for other configurations of the fertigation system.