A review of hundreds of nutrient solutions and all greenhouse growing systems showed one thing in common, the absence of silicon and a range of other naturally occurring elements. The fact is that we attempt to grow healthy productive plants in isolation from some of the nutritional inputs they were evolved to require. It is obvious by now that silicon and other rare earth elements are of benefit as a nutrient component for greenhouse and Hydroponic growing systems. The real problem for growers has been finding a source of them in an economically and useful form. Potassium silicate is too pH sensitive and expensive, and pure silicic acid is not feasible as an additive.
Pyrophyllite clay is the natural answer.
The publicity from China about their claims for the effects of rare earth elements on plant growth has focused attention on this aspect of plant nutrition. The purpose of the trial was to determine the impact of silicic acid as a fungicide on chrysanthemums. While the trial was successful in its purpose, there were additional unexplainable results. The grower noted improved color, and enhanced health and vigor. For our purposes in nutrient formulation, it is becoming obvious that we need to include a much broader spectrum of elements in the nutrient solution.