There is limited information about seedlings technology production of Prosopis alba ("algarrobo blanco" tree), a native species of commercial importance in Argentina. Therefore, the objective of this present work was to evaluate the effect of different substrates and containers on P. alba seedlings growth in two nurseries with contrasting environmental conditions. Composted pine bark and soil (CPT) and composted pine bark, perlite and vermiculite (CPV) mixtures were tested in 10 types of containers with different heights and volumes. For each combination of substrate and container, total porosity (PT), water retention (RA) and aeration porosity (PA) were measured. All these properties were influenced by container characteristics and substrates, showing the highest PT and PA values in CPV and bigger containers, while the RA was higher in CPT and smaller containers. Seedling growth, measured as seedling collar diameter (DAC) and total height (AT) was affected by the substrate and container type, showing higher growth in bigger containers. Furthermore, growth increased with volume and diameter of the container, being less influenced by the height. As a result, containers choice must be done based on the size and desired seedling production time, along with substrates that balance good porosity and water retention.