In Andisols of Southern Chile, crop yield is mainly limited by P fixation and aluminum phytotoxicity (Al3+), but scarce information in these soils is known in rotations, including wheat after Andean crops. It is very relevant to the knowledge of suchcrops’ root architecture to improve productivity through a greater absorption capacity of water, nutrients, and tolerance to biotic and abiotic stresses. The objective of this work was to evaluate root architecture at early phenological stages of Andean crops in an acidic Andisol from Southern Chile. During the 2019/2020 season, a field trial was established using four non-mycorrhizal cultures: Buckwheat (Fagopyrum esculentum L.), amaranth (Amaranthus spp.), lupine (Lupinus albus L.), and quinoa (Chenopodium quinoa L.), and compared with oats (Avena sativa L.) a mycorrhizal culture. During the growth period, four plant and soil samplings were carried out, evaluating phenological stages, root architecture, together with soil pH and P-availability. During the first half of the vegetative cycle, the growth of the crops was continuous but drastically reduced at the end development cycle due to the prevailing drought during the summer months. These climatic conditions affected quinoa and lupine growth showing high sensitivity to water stress. In general, all crops showed good root architecture, suggesting a more efficient P mobilization. A greater root length was obtained in buckwheat, while a better adaptation capacity to the environmental conditions was observed in quinoa. It is concluded that through suitable agronomic management by incorporating quinoa or amaranth as pre-crops of wheat in a rotation, the P-availability for the next crop could be increased by reducing the application of chemical fertilizers.