World-class nutrients for plant growth in soil, hydro and coco A passion for growth and bloom, a commitment to quality and a deep-rooted knowledge of what makes plants grow has been the trademark of HESI and its world-class line of nutrients and supplements. HESI is designed to stimulate plant growth and increase yields by integrating optimal vitamin compounds geared towards each phase of the plant's life cycle. The secret of HESI's potency is not really a secret at all! It comes from years of experience and scientific know-how all combined with a passion for quality. It's the science behind growth and bloom that makes HESI the grower's choice.