Published results & grower experience
Bring biodynamic preparations into your soil and field management.
Pfeiffer Field and Garden Spray is formulated for soil and field applications, including work with incorporated crop residues. Published vineyard accounts offer a practical example of its use alongside cover-crop management.1, 5, 6
The Grgich Hills experience
In a published interview, Ivo Jeramaz described a comparison begun in 2007 with fifty treated acres and a fifty-acre control. Juice nitrogen in five of six treated blocks reportedly rose from approximately 150 ppm the previous year to 200 ppm after Field and Garden Spray use.5
A later account identifies the measure as yeast-assimilable nitrogen (YAN) and reports no increase in the untreated blocks. YAN describes nitrogen available to yeast in grape juice. These are published grower accounts of a commercial comparison; they do not supply a randomized statistical analysis.6
A grower's recommendation
Jeramaz's interview, published in Winter 2010-2011, includes this recommendation:
Nonetheless, I would highly recommend it where possible, especially if you have good moisture and good cover crops.5
Moisture and management mattered. The interview reports little improvement in dry 2008 and later discontinuation because of application logistics. The 2015 account describes dry-year exceptions and eventually reducing annual application when YAN became too high for the wine being made. The accounts differ in their follow-up chronology.5, 6
Put the experience to work
Follow the current product instructions for preparation, coverage and application timing. Record your cover crop, soil conditions and application date so that the reported experiences can inform your own observations.12
Sources for this product section
- Josephine Porter Institute, current product descriptions: Biodynamic Pfeiffer Compost Starter and Pfeiffer Field and Garden Spray. Consulted September 27, 2026. These identify current products and intended applications; the historical comparisons are documented separately below.
- Hunter Francis, "Biodynamics Taking Root in the Legendary Napa Valley," interview with Ivo Jeramaz, Applied Biodynamics 71 (Winter 2010-2011), p. 5. Vineyard comparison, follow-up conditions and recommendation.
- Abigail Porter, compiler, "Anecdotes: Pfeiffer Biodynamic Field and Garden Spray," Applied Biodynamics 87 (Spring/Summer 2015), p. 17. Vineyard account attributed to Joseph Brinkley's experience. Its phrase "50 mg" lacks a denominator; the surrounding discussion uses mg/l. The numerical table in this guide uses the 150-to-200 ppm values in reference 5.
- Josephine Porter Institute, Pfeiffer Compost Starter instructions, Field and Garden Spray instructions, and preparation-instructions directory. Consulted September 27, 2026. Use the current instructions supplied for the product being applied.