Horsetail tea
Horsetail tea (also called horsetail decoction) is a boiled extract of field horsetail (508). Its high silica content is used to keep fungal pressure on soil and plants in check preventively.
What is horsetail tea?
Horsetail tea, also called horsetail decoction, is the usual way of applying field horsetail (508). It is a boiled water extract of the dried or fresh plant, which is diluted and sprayed onto soil and plants. The aim is not to kill fungi but to strengthen the plants preventively against fungal pressure.
What makes it work is horsetail's high silica content. Through the "light forces" of silica, it is credited with fungus-inhibiting properties that make the plant firmer: the plant becomes more resistant and its surfaces are strengthened. This is also an established use in organic gardening in general.
How to make it
About 200 to 300 grams of the dried plant (or 1 to 1.5 kilograms fresh) are simmered gently in 10 to 20 litres of water for about an hour. The decoction is then left to cool and strained. This concentrate is diluted to five to ten percent before it is applied. Only field horsetail (Equisetum arvense) is used; marsh horsetail and wood horsetail are unsuitable.
How to use it
The dilution is sprayed onto soil and plants at about 100 litres per hectare. The timings are spread over the year: in autumn (into November), in spring (from February or March) and in high summer. What matters is using it preventively and repeatedly: horsetail tea is not an emergency fungicide for an acute infection, but strengthens the plant in advance. In vegetable growing, autumn treatment is preferably given to the areas that will carry crops prone to fungal disease the following year. As with horn silica, spraying is preferably done in the morning in clear weather.
Frequently asked questions about horsetail tea
What is horsetail tea good for?
Against fungal pressure, preventively and as a strengthener, thanks to the high silica content of field horsetail. It does not kill fungi, but makes the plant firmer.
How is horsetail tea made?
The dried plant (200–300 g in 10–20 l of water) is simmered for about an hour, strained, then diluted to 5–10 % and sprayed.
When is it used?
Preventively and repeatedly: in autumn, spring and high summer, preferably in the morning in clear weather.