The plant cell wall, a complex cellular structure that surrounds all plant cells, plays an essential role during plant growth, but also acts as a physical barrier against environmental stresses. Understanding the growth mechanism of a plant cell wall is of fundamental importance for improving crop yield. In particular, the enzymes that regulate and modify the complex structure of the cell wall need further attention. We use the onion bulb epidermis as a model for growth studies. As the bulb is organized in different layers of different ages, this provides the possibility to study different growth stages within the same individual. Our work focuses on understanding and characterizing the molecular mechanisms that mediate plant growth through the differential expression of genes that metabolize the cell wall. Likewise, we study the involvement of cell wall compounds in this growth using biochemical techniques and microscopy. A total of 10 genes encoding enzymes participating in the regulation and maintenance of the cell wall (Expansin, Fucosidase, Galactosidase, Glucanase, Pectin methylesterase, Pectin/pectate lyase-like, Polygalacturonase, Xylanase, Xyloglucan endotransglycosylase/hydrolase, Xylosidase) were selected and their expression was studied using RT-qPCR. We identified a significant difference in the expression of cell wall enzymes and in their correlation with cell wall composition in different growth stages. These results provide evidence that the onion epidermis can be an excellent model for studying plant growth. Our recent progress in the mathematical modelling of the cell wall growth mechanism will be presented.