Plant quality is an important factor in the success of reforestation actions. The current guidelines attempt to produce quality plants by optimizing various phases of production process in nursery. The goal is to overcome the drawbacks of traditional breeding of plants (polyethylene bags, uncontrolled substrate, etc.) by choosing appropriate methods and standards of high quality plants production. Obviously, each combination species-type of production has its own breeding requirements. Hence, this work is carried out to determine the effect of the container dimension/ substrate type on growth and morphological variable of Atlas cypress (Cupressus atlantica Gaussen) seedlings. The experimental design compared the effect of two independent factors : (1) the type of substrate mixture (forest soil-compost ; forest soilpeat, compost-forest soil-peat, peat) and (2) the type (polyethylene bags or container) and the container size (300 cm3, 400 cm3 and 500 cm3). Several morphological parameters were measured such as the height of the stem, root collar diameter, the vigour quotient and the fresh and dry weight both of the roots and the aerial part of the plant. The description of the root system aimed to quantify the number of lateral roots and the pivot length. The root hairiness, the branching degree and the presence-absence of root deformation were also evaluated. The conclusions emanating from this work show a positive effect of peat on the survival and the installation of seedlings. The two studied factors constitute different breeding modalities with significantly contrasted performances. The combination of mixed substrate soil-compost-peat and the container of 500 cm3 was indisputably observed as the most appropriate for plant production. It allows the production of vigorous plants whose growth (height and diameter), biomass, density and branching of the root hairs are significantly higher. This experimentation constitutes the first step towards the development of the production norms specific to the cypress plants. She answers the imminent concerns of the plant nurseries called to change their traditional technique of plants production and to support effectively the afforestation programme.