Sweet alyssum (Lobularia maritima L.) is known as an insectary plant with great potential in enhancing the occurrence and diversity of beneficial insects in different crops. However, agronomic aspects of the introduction of this plant are still not fully recognized. Field studies aimed at assessing entomological relationships in the quasi-coordinate system focused on evaluating the impact of sweet alyssum as a companion plant in broad bean (Vicia faba L.) cultivation on the prevalence of the black bean aphid (Aphis fabae Scop.) and its natural enemies. It was also sought to determine the optimal row spacing for broad beans when introducing an additional plant between the rows. A 3-year field experiment involved various row spacings for broad beans: 50 cm, 65 cm, and 80 cm, with a control group at a 50 cm row spacing representing conventional cultivation, and another group with standard chemical pest protection as a reference. The results indicated that using sweet alyssum as a companion plant significantly reduced the black bean aphid population. It was comparable to the effect of chemical pest control. This companion planting also considerably increased the population of natural enemies of the black bean aphid, including hoverfly eggs and larvae, as well as various stages of ladybirds, particularly the adult stage. Sweet alyssum contributed to a reduced aphid-to-predator ratio, leading to a significant decrease in black bean aphid numbers and an earlier colonization of aphids by hoverflies and ladybirds on broad bean plants. In summary, sweet alyssum has the potential to effectively decrease black bean aphid occurrences, particularly on ecological farms. Notably, sweet alyssum's competitiveness with broad beans and the different row spacing had minimal impact on predator occurrence, eliminating the need to increase standard row spacing for this plant.