BD 500
BD 500, or Horn Manure (500), sounds like some kind of an energy drink, but it is essentially fermented cow dung buried underground and later unearthed. It is the basis for soil fertility and the renewal of degraded soils in biodynamic viticulture.
BD 500 is typically prepared and buried in Sep/Oct and lifted in Feb/March. (I need to check if this is the case in Europe.)
Materials
- Cow horns
- Fresh cow dung from a lactating cow. Average 50-150 grams of dung per horn (but depends on horn size)
Preparation process
- Feed cattle with high-quality food for two days before collecting dung for BD 500
- Prepare burial pit: 18 inches deep. The pit area should not be subject to flooding, vigorous root systems or earthworms.
- BD 500 takes the character of the soil it is buried in, so good quality earth in the burial pit is essential.
- Collect cow horns – remove any paint.
- Collect fresh dung – reasonably firm.
- Fill cow horns with cow dung in Sept/Oct
- Place horns in burial pit, 1 inch apart with base downwards, surround with 50% compost and soil.
- Cover with soil and bury for 4 to 6 months. If the soil is not rich enough, add compost to an extent of 50% to enhance soil quality.
- Keep burial pit soil moist and shaded, and free from weeds and earthworms.
- After 4 months, check for dung fermentation. Dig up one horn. They are ready to be lifted if the green cow dung has turned into a dark, smooth, earthy smelling humus (BD 500).
- Remove the BD 500, use and store. If not, leave them longer.
Application process
- Apply when the dew is falling (the earth breathes in) i.e. late afternoon or evening
- 25 grams of BD 500/acre in 15 litres rain/pure warm water (approx. 15-20 °C)
- Check water for high calcium, iron or other minerals
- Stir for 1 hour alternately clockwise and anti-clockwise, forming a vortex
- Spray in the late afternoon or evening (just before sunset), when Moon is descending
- Spray 4 times a year
Storage
- Place in glazed earthenware pots with loose-fitting lids.
- Bury in a box surrounded with coir pith, which is kept moist and can be closed.
- Keep in dark and at temp of not more than 25 °C.
- Use within 1 year.
Typical Mistakes?
- Wrong Quantity: Too much or too little of BD 500 can lead to a Goldilocks dilemma.
- Bad Timing: Spraying during the heat of the day? Nope.
- Inconsistent Stirring: Remember, vigorous stirring for an hour. No shortcuts.
Commonly Shared Tips?
- Stirring Technique: Alternate between clockwise and counter-clockwise stirring.
- Monitor Weather: Avoid spraying if rain is forecast within 48 hours.
- Follow the Calendar: Biodynamic calendars are like winemaking horoscopes, so pay attention.