Application of biostimulant in the form of a spraying requires appropriate selection of technical parameters. One of the key factors in ensuring that the liquid is sprayed correctly is the choice of suitable spray nozzles. This study investigated selected technical parameters of seaweed biostimulant spray applications as a factor for plant biometrics, crop quality and yield, and the economic viability of production. This objective was achieved by conducting a two-year field experiment involving spraying soybean plants with a biostimulant containing seaweed extract. The spraying was carried out with two types of nozzles (standard and air-injector), for which the droplet size and the degree of plant coverage were tested at 4.0 MPa. The surface tension of the spray liquid and the area and volume of the droplets were tested. The height of soybean plants, the height and the position of the first pod, the number of pods, seed yield, and the weight of 1000 seeds were measured. The physical properties of the liquid sprayed on the plants and the type of nozzles used were factors affecting the height of the first pods, plant height, and protein content. The application of biostimulants using standard nozzles is more economically advantageous compared to nozzles with an air-injector