Horn silica (501)
The light preparation — for ripening and expression.
Horn silica (preparation 501) is the “light” counterpart of 500. Ground quartz is fermented in a horn over summer and then dynamised and sprayed as a very fine mist over the canopy.
It is used to reinforce light metabolism, photosynthesis and ripening, and practitioners associate it with aromatic definition and clarity in the wine. It is applied early in the morning, typically on fruit/flower days, sparingly to avoid over-exposure.
Effort
Medium — occasional applications in the ripening phase.
Cost
Low — minimal quantities.
Time to result
Within the season, in ripening and tasting.
What it advances
Contribution by goal — click through for detail and metrics.
Plant vitality & resilience
It is the preparation used to reinforce light metabolism and photosynthesis, supporting ripening and canopy health.
Time horizon: 1 season
What to measure for this pairing
Wine expression & quality
Practitioners associate 501 with aromatic definition and clarity in the wine — the preparation most tied to expression.
Time horizon: 1 season
What to measure for this pairing
Demeter certification
501 is one of the preparations Demeter requires; its application must be documented.
Time horizon: Ongoing
What to measure for this pairing
How it works
Dynamised in water and sprayed as a fine, upward mist over the canopy, it is used to reinforce photosynthesis and ripening.
How to apply
- 1Dynamise in water for an hour at dawn.
- 2Spray as a fine mist over the canopy early in the morning.
- 3Apply sparingly, on fruit/flower days.
- 4Log rate, plot and date.
What to measure
Frequently asked
Can 501 cause sunburn?
Applied in excess or in intense heat, the boost in light activity can worsen stress. That is why it is applied sparingly and early in the morning.
When is 501 applied?
Mostly in the ripening phase, early in the morning and on fruit/flower days, to support photosynthesis and fruit definition.
Related reading
Related practices
How GrapeFlow helps
Plan and document this practice by plot, with an audit-ready history for Demeter certification.
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.
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.
Tasting notes & analyses
Per-lot tastings and analyses over time, to relate the biodynamic programme to how the wine evolves.
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