The most serious of these is to stimulate the development of sustainable and, at the same time, environmentally friendly systems. Therefore, this study aimed to determine the effect of two biostimulants on the bean yield and fiber fractions in seeds: neutral-detergent fiber, acid-detergent fiber, lignin, cellulose, and hemicellulose. The field experiment performed in 2016–2018 in Poland. Over the growing season, plants were treated with biostimulants seaweed extracts (concentrations of 0.7% and 1%) and amino acids (0.3% and 0.5%) based products. Plants were sprayed a single time in the Biologische Bundesanstalt, Bundessortenamt and Chemical industry (BBCH) 13–15 phenological phases and a double spray in the BBCH 13–15 and 61. The study showed a significant increase in bean yield (average 32.08% compare to control) when seaweed extracts was used in the form of a double spray at a higher concentration. In the case of the application of amino acids-based product, the best results (increase of 21.97%) were obtained using a double spray at a lower concentration. It was found that the tested biostimulants changed the fiber fractions of bean seeds. The acid-detergent fiber (ADF) content was the highest (average increase of 2%) after double plant treatment with seaweed extracts based product. While the increased concentration of neutral-detergent fiber (NDF) (over 4%) resulted from double spraying with lower concentration of this biostimulant. The increase in the lignin (ADL) (1.12%), hemicellulose (HCEL) (4.54%), and cellulose (CEL) (0.91%) represented plant response to the double application of this biostimulant in the higher concentration. The results indicated also that the use of amino acids-based product caused an increase in the ADF (0.28%), NDF (10.27%), ADL (0.63%), and HCEL (9.99%) contents in bean seeds as an effect of double plant treatment with this biostimulant at lower concentration.