We conducted a study of soil quality in traditional backyards (family orchards) in the tropical humid southeast of Mexico. The aim of the study was to increase soil fertility by the inoculation and reproduction of cultured earthworms and leguminous plants. Individual earthworms of Glossoscolecidae sp and Dichogaster saliens (oligochaeta) were introduced in soils with fresh organic matter. The highest earthworm growth rate (3 mg day-1) was found in substrates with 1.5% Mucuna pruriens var. utilis (leguminous). Cultured earthworms (27 gm2) were introduced during the rainy season. We established four backyard treatments with six replicates 3 x 2 m each. The highest organic matter content (5.45 ± 1.6%), total nitrogen (0.27 ± 0.05%), extractable phosphorous (40.6 ± 22.5 mgkg-1) and potassium (1.05 ± 0.88 mgkg-1) was found in soils treated with earthworms and Arachis pintoi, with a significant difference (p < 0.05) from the control treatment.