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.
Plant vitality & resilience
It is the plant preparation used to reinforce resilience and disfavour fungi, supporting vine health.
Time horizon: 1 season
What to measure for this pairing
Demeter certification
Horsetail is part of the biodynamic preparation set; its use is documented in the Demeter programme.
Time horizon: Ongoing
What to measure for this pairing
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.
Weather & spray windows
A 7-day per-plot forecast with the windows where applying makes sense — wind, rain and humidity decide the hour as much as the calendar does.
Electronic field notebook (Portugal)
In Portugal, every operation — compost, cover, animals, treatments — logged by plot, with the DGADR notebook filling itself and staying certification-ready.
Phenology & field observations
Budbreak, flowering, veraison and everyday occurrences logged by plot and date — the vineyard’s real calendar, the one any work programme is read against.
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