Liquid Silicon liquid silicon, the missing element Silicon is a beneficial plant nutrient found in virtually all natural soils but not, until now, in hydroponic nutrient solutions. Silicon will strengthen the plants cell walls producing stronger healthier plants with massive root systems and increased resistance to pests and disease. Liquid Silicon is highly beneficial to plants in the range of 20–50 ppm in the nutrient solution. It is not included, and cannot be included, at these levels, in nutrient concentrates. It needs to be added as a separate component by the grower. Liquid Silicon can be added to nutrient tanks every time a fresh batch is made.