501 Horn Silica

There are 2 main biodynamic preparations , the so-called “spray” ones:  500  and  501 , obtained from two different substances.

The preparation  501 , or Horn Silica is used, depending on the type of plant, either when the leaves are developing or when the fruits or roots are forming. Its action is to strengthen the effects of light and heat on the plant and promote healthy growth.


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The raw material is rock crystal, taken from quartz quarries present in many mountains, for example in the Tuscan-Emilian Apennines. Sand or feldspars can also be used as a source of silica, but rock crystal represents perfection, purity: Steiner himself indicates that he prefers rock crystal. Upon analysis it contains up to 98% silica (SiO2) compared to 75-80% in sand. In spring, the best, most crystalline and transparent part of the crystal itself is taken and we proceed to the most delicate phase, the milling, which must be pushed to the maximum to obtain a very high degree of finesse. Purity and fineness are necessary because silica is not soluble in water.

With deep milling it is possible to overcome the problem of solubility, obtaining a stable suspension of silica in water.

Silica is also placed in the horns, added with pure water and then buried from spring to the following autumn.

Once again the quantities to be used are very small: 3 grams in 50 liters of water per hectare.

Corno Silice
How to use

Dynamization and spreading 501

The suspension obviously must be dynamized as is done for the 500 . Unlike 500, which must be applied to the soil in large drops, 501 cornsilica is sprayed on the leaves in spring, at the time of vegetative growth, when photosynthesis is reactivated.

It is important that the nebulization is very thorough, obtained using high pressure pumps, without recirculation: that is, the droplets must be micronized, so that the suspension does not drain onto the leaves but becomes fixed in the atmosphere. The light, through the crystals contained in the suspended droplets, is refracted and therefore broken down into different chromatic bands. Even if it is not proven, different actions of the multiple chromatic components of light on photosynthesis can be assumed.

The greater the degree of subdivision of the rock crystal, the greater the number of particles capable of breaking down light, the greater the activity of the silica and, consequently, its effectiveness. The treatment should be done early in the morning, when the light is transversal and there is greater refraction; but also because in the early morning there is no wind.

This stimulus at a high level, of light, integrates with that at a deep level, of humus: in this way the dynamic action on the plant is complete and growth is balanced. Instead, the administration of "500" alone can determine the development of hypertrophic plants, unbalanced due to excess nutrition and growth. I insist: the action of the two preparations "500" and "501" must not be understood as separate on different organs or functions of the plant. It is their combination that determines the balanced stimulus at the level of the terrestrial and cosmic sphere and therefore the harmonious development. Furthermore, the "501" not only has a quantitative action on the intensity of photosynthesis and the accumulation of sugars, but also and above all on the quality of light.