The present work investigated the effects of a combined biostimulation treatment of some agricultural crop seeds on their germination and seedling growth. The biostimulation consisted of two steps: a pretreatment of the seeds by immersion into a clay-lignocellulose solution and their laser exposure at 532 nm wavelength. Three agricultural crop species were selected for the treatment, namely, wheat (Triticum aestivum L.), corn (Zea mays L.) and bean (Phaseolus vulgaris L.), which can be considered as key staple crops for most of the global human population. The study revealed that the crop seeds subjected to the combined treatment, involving 7 min laser exposure, presented the shortest germination period among all the sample series, especially as regards the beans, which exhibited a 50% reduction of the germination period from 120 h (control) to 60 h. Also, the combined treatment (with 7 min irradiation) induced obvious growth stimulation, leading to enhanced seedling growth rates, specifically, of 71.8% for wheat, of 54.5% for beans and of 47.61% for corn, as compared to the control samples measured 72 h after planting.