Grow Systems Hydroponic systems are classed as either active or passive, the majority of our hydroponic systems are active offering the best results. Active hydroponics is when nutrient solution is actively delivered to the plants roots via a pump. No growing medium is necessary in active hydro; which allows an abundance of oxygen into the root zone. This constant supply of oxygen, water and nutrients results in optimum growth and yields. Passive hydroponics is when nutrient solution is constantly available to the plant via the capillary action of the growing media, there is no pump involved. Although more effective than traditional growing methods: passive hydroponics relies on absorbent growing medium, limiting the amount of oxygen in the rootzone compared with active hydroponics.