Horsetail (508) — a portrait of the silica preparation

Field horsetail (Equisetum arvense) bears the number 508 and holds a special position in the canon: it is not an earth preparation in an animal sheath, but is applied as a tea or decoction — preventively against fungal diseases. Its strength is silica. This portrait covers the plant, its mode of action, making and application.

The plant

Equisetum arvense is a primeval plant without flowers that reproduces through spores and a widely branching rhizome system. In the "Agriculture Course" (GA 327), Steiner points out that field horsetail consists of around ninety per cent silica — the same substance that is also active in quartz and thus in horn silica (501), here however in a fine, living distribution. Important: only field horsetail is used, recognisable by its rough, furrowed summer shoots with their upward-curving branches.

Mode of action: silica against fungal pressure

Horsetail strengthens plants against fungal diseases. Pierre Masson describes the picture vividly: horsetail, which tolerates damp sites without rotting itself, conveys to the fungi and to the lunar forces that stimulate them that they should confine themselves to the soil instead of attacking the parts of the plant above ground. The preparation therefore works preventively and in an ordering way, not as a chemical fungicide.

Making and application

Horsetail is collected and dried in summer. For application, it is boiled as a decoction and diluted — sprayed preventively on the soil of crops at risk of fungal disease, in spring from March to May and in autumn from October to November. According to Masson it works best in the morning and close to the full moon or the moon's perigee, because these are favourable times for fungal diseases to develop. In fruit growing and viticulture, adding it to tree paints has proven itself. More on application in Horsetail tea.

Frequently asked questions

Why does horsetail work against fungi?

It is very rich in silica and strengthens plants preventively. In the biodynamic view, it keeps the fungal pressure in the soil instead of letting it spread to the parts above ground.

Which horsetail is the right one?

Only field horsetail (Equisetum arvense), recognisable by its rough, furrowed shoots with upward-curving branches — not to be confused with other species.