Description
Description
At a Glance:
One unit is 1/4 cup.
One unit treats one acre.
What it does:
BD 500 is JPI's horn-manure soil spray for nurturing living soil, root growth, and humus-building conditions. Published wheat and maize field experiments measured greater root dry matter in biodynamic preparation programs that included horn manure.
Does BD 500 replace nitrogen fertilizer?
At the whole-farm level, yes. Biodynamic management with BD 500, manure compost made on the farm, legumes, and living soil can achieve $0 bought-in nitrogen fertilizer, including $0 conventional nitrogen fertilizer. Researchers cultured Azotobacter and Azospirillum—free-living and root-associated nitrogen-fixing bacterial groups—from sampled BD 500. Legumes bring atmospheric nitrogen into the system, and on-farm manure compost cycles nutrients. In the long-running DOK biodynamic treatment, manure compost and slurry were used without mineral nitrogen fertilizer. This is a synergistic whole-farm result, not a bag-for-bag nitrogen dose from one BD 500 spray; the bacterial study counted organisms present rather than measuring nitrogen delivered per application.
How to use:
Stir one unit for one hour in 3 gallons of lukewarm rainwater or other chemical-free water, ideally in the late afternoon. Spray immediately on moist soil, not on foliage. Apply mainly in spring or fall, shortly before sowing or transplanting.
After I stir Preparation 500, how quickly should I spray it—within one hour or within three?
- Podolinsky: Spray Preparation 500 within one hour where possible.
- Pfeiffer: BD 500 is strongest within three hours, later loses strength, and “becomes useless if left overnight.”
Practical direction: Spray immediately after the full hour of stirring. Three hours is the outer strength window, not a reason to delay.
Why it is called “500”:
According to Alex Podolinsky, Ehrenfried Pfeiffer named the preparation “500” because properly wintered horn manure contained, per gram, “500 million aerobic bacteria, partly of a totally new kind.” Podolinsky concludes: “For this reason he named this substance ‘500’.” In Podolinsky’s account, the name refers to that bacterial count, not to an application rate.
How did Podolinsky describe the transformation of cow manure into Preparation 500?
Alex Podolinsky describes cow manure changing through the freezing winter, when bacterial activity is suppressed, into “active-creative humus 500.” This substance then undergoes the energising vortex/Chaos process, from which soil-structuring and plant-forming Bio-Dynamic power arises. In his exact phrase, “Individuality arises in adversity.”
Source: Alex Podolinsky, Living Knowledge (2002), p. 25.
Dose and carrier-water clarification:
One 1/4-cup unit is the BD 500 material dose for one acre. The 3 gallons is carrier water in which that unit is stirred and applied; it is not the amount of BD 500 material. In Podolinsky’s broad-acre context—one owner-operator, the sole farm worker, covering 1,000 or more hectares—his exact rate excerpt is “88g/Ha (1¼ to 1½ ounces per acre), with a droplet per square centimeter,” with the compost preparations added in their appropriate quantity. This is his historical Prepared 500 broad-acre method. JPI’s current 1/4-cup unit per acre remains the current retail direction; the measures may be placed side by side as practical context without mathematically converting mass and volume or changing the current mixing steps.
Ingredients:
Cow manure aged underground for 238 days. The cow horn is used only as part of the traditional production method; no horn material is contained in the finished preparation.
Organic pre-harvest interval:
Under Accredited Certifiers Association guidance for horn manure, the applicable 90- or 120-day interval begins when the filled horn is buried. This preparation is aged underground for 238 days, so that interval has elapsed before the finished product is removed and sold. Application does not restart the interval.
Use:
For agricultural use only. Apply to soil after stirring and dilution as directed. Not for human or animal consumption.
🌱 Learn More about BD 500 Horn Manure
Product Details:
JPI applies BD 500 to moist soil shortly before sowing or transplanting, or when incorporating a cover crop, to support soil activity and root development. In two published field experiments, biodynamic preparation programs measured 12–39% greater root dry matter and 10–37% greater root length than organic treatments, depending on crop, year, and preparation use. Those programs included horn manure alongside horn silica and compost preparations. The Washington trial's preparations came from Josephine Porter.
How to use BD 500
Stir one unit for one full hour in 3 gallons of lukewarm rainwater or other chemical-free water. During the last 20 minutes, add one unit of BD 507 per acre for best results. Spray immediately after stirring, during the latter part of the day, directly on moist soil. Part portions may be used for smaller areas, keeping the same proportions and stirring for the full hour.
Preparation labels: BD 500 and 500X are labels for the same one-unit inventory item. BD 500P is a separate preparation with separate inventory and is sold separately.
BD 500 Detailed Usage Instructions: English | Spanish | Chinese
Additional Article: BD 500: Reflections on Making BD 500
Please note: Quantities over 1 may be bagged together.
Frequently Asked Questions
How do I use Biodynamic® Horn Manure Preparation?
What is the coverage area for BD 500?
When should BD 500 be applied?
Can BD 500 be combined with other preparations?