Horsetail (508)
The plant preparation to reinforce fungal resilience.
Horsetail (preparation 508) is made from Equisetum arvense, rich in silica. It is prepared as a decoction or tea and sprayed over the vine and soil, especially in humid periods.
In biodynamic practice it is used to reinforce plant resistance and make the environment less favourable to fungal development. It does not replace copper and sulfur in disease control, but is part of the preventive programme. It is an input compatible with organic and recognised in biodynamics.
Effort
Medium — preparation and applications in risk periods.
Cost
Low — a common plant, can be gathered/grown.
Time to result
Preventive, within the season.
What it advances
Contribution by goal — click through for detail and metrics.
How it works
The silica-rich decoction is sprayed over the plant and soil, used to reinforce resilience and disfavour fungi in humid periods.
How to apply
- 1Prepare the horsetail decoction/tea.
- 2Spray over the vine and soil in humid periods.
- 3Fit into the preventive programme, not as a copper replacement.
- 4Log the applications.
What to measure
Frequently asked
Does horsetail replace copper?
No. It is a preventive reinforcement within the programme; downy-mildew control still rests on copper and good preventive practice.
When should it be applied?
Mostly in humid, higher-fungal-risk periods, often in combination with the rest of the preventive programme.
Related reading
Related practices
How GrapeFlow helps
Plan and document this practice by plot, with an audit-ready history for Demeter certification.
Preparations & application log
Every application of 500, 501 and the other preparations logged by plot, date and rate — the history the Demeter audit asks for.
Electronic field notebook
All operations — compost, cover, animals, dynamisation — logged by plot, ready for certification.
Biodynamic calendar
Root, leaf, flower and fruit days and the lunar phases in GrapeFlow, to plan preparation applications and work in step with the calendar.