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The Bio Bros: Preparations
Trevor Harris on the nuts and bolts of biodynamic preps
June 17, 2022 | editorial | 10 minute read

It’s the preparations, and their application, that really distinguishes biodynamics from organics. If organics is defined by what you don’t do — no chemical pesticides or fertilisers — biodynamics is about what you do.

The preparations are esoteric, even thought of as eccentric by some. Yet the results speak for themselves; not only do many of the world’s greatest wineries now follow biodynamic principals of agriculture, but our own biodynamic barley distillate is proving more intense in aromas and flavours than either our organic or conventional spirit in blind sensory analysis, as explained by Terroir Specialist Angelita here.

(Not to mention that the bottles of Biodynamic: Luna are always the first emptied at whisky tastings and festivals.)

Given the importance of the preparations to the biodynamic process, and thereby to the character and intensity of the barley’s flavour, we thought it was worth investigating them in greater detail. Trevor Harris was happy to talk through what’s involved. Over to you, Trevor.





The first prep is the one that’s based around the soil. That’s 500, and you can take it a step further and have what’s called Prepared 500, or 500P. 500 is horn manure and prepared horn manure has compost preparations in it as well. That’s what we use.

This was something that was trialled by Alex Podolinsky, who was heavily involved in bringing biodynamic agriculture to Australia. Because of the vast acreages they were covering it was going to be a physical impossibility to get compost on every acre. So he had to come up with a solution and the solution was the Prepared 500. Because it already had the compost preps in it, they were going on the soil with the 500.

What Prepared 500 is doing with the soil is it’s aiding the structure. It’s affecting the physical characteristics of it; it’s aiding the advancement of the biology, so it’s improving the biological aspect. It’s also affecting the balance of nutrition, the balance of chemical elements that are in it — the nutrition that the plant needs. So it’s affecting the ‘three legs of the stool’. They say to have a well-balanced soil it’s you need the three legs, one biological, one chemical and one physical. In chemical agriculture a lot of the time they just focus on the chemicals; they focus on the nitrogen, the phosphorous and the potash and once those are right they think that everything will grow perfectly. But in biodynamics we focus on all three. Obviously I’m not applying chemical fertiliser but I do pay attention to what mineral nutrients are available to the plants in the soil, and they have to be in a plant-available form; I want them in a natural form. And the 500P will help with that.


There’s a very specific way to make 500P. In the autumn you gather up manure from a lactating cow and the same day you put it into a cow horn and bury it in the ground. You have to pick a particular day to do it – you won’t just bury one horn; you’ll fill and bury a number of them. Then you leave them there over winter and then in the springtime after all the soil forces and the cosmic forces have had time to act on those horns you dig them up, extract the manure and store it in a special vessel inside a peat-lined box to allow it to mature. So it’s a bit like a fine wine! It doesn’t come out of the ground necessarily ready – you put it into storage and you leave it for a period of time, monitoring it to make sure it doesn’t dry out; it could take a year for it to mature properly. So it’s quite a specialised process. Then to make prepared horn manure, after it’s matured to a certain stage you add the compost preps and then store it for another period of time.

When you have your prepared horn manure it’s time to apply it. There are different times you can apply it; we apply it as soon as the seed is in the ground. First you heat 250 litres of water to about 30 degrees-35 degrees celsius and then you put in 700 grams of horn manure, which is enough for seven hectares. Then you stir it for exactly an hour in a very particular way, which our machine does automatically, and you apply it to the soil within two hours.

The affect of applying this after sowing the crop is that it aids the germination and it aids the vigour of the plants. It’s really encouraging and quite impressive to see the effect that the application of 500P will have on a crop. It’s great that you can apply something like that and actually see the results.


501 is horn silica, and it’s the other essential prep. What you do is you gather up quartz crystals and you grind them into a really fine powder. It’s important that it’s really fine, because if you don’t grind it up fine enough and you apply it to your plants, it makes them lethargic, and that’s the last thing you want.

In springtime you grind up the crystals, you mix them with clean rainwater, put them into cow horns and bury it for the summer. In the autumn you dig it up, take it out of the horn and store it in a glass jar where it’ll be dry but warm in the sunshine.

When you want to apply that you take four grams of it per hectare, so you’d add 28 grams to the stirring instrument which does seven hectares. Stir it for an hour in water at 30-35 degrees and then apply that early in the morning. And that’ll have a positive effect on the photosynthesis of your plants.

Most of the time you apply it during the growing season, possibly two or three times depending on how the season’s going. We also apply it combined with the horn manure in the winter, but the idea is that it’ll improve the photosynthesis of the plant, and they say that it’s like getting an extra 2-4 days of sunshine. We’ve been lucky recently but generally you get less sunshine in County Kildare than you would in France or Spain!

When you apply 501 it also strengthens the cell walls; it strengthens the plant in general, so it’ll give the plant a good, strong, upright stance which is all positive.

Visible results … and it’s not just Trevor who says so

I do some contract spraying for other farms, and I remember one farmer who had been skeptical ringing up and saying ‘I can actually see it happening’. He wasn’t sure whether I was going to see him as a fool! But I’d applied 500P and 501 to his field and the following day he rang me and he said “should I be seeing anything?” And I said “yeah, you should”, but I wasn’t going to tell him what he should be seeing – I wanted it to come from him. He said “I noticed that the colour of the field is different than what it was yesterday – the plants are all really upright”. And I said “that’s exactly what you’d expect”.

The 501 gives the plant an upright effect and it affects the photosynthesis of the plant. So what he told me was that he’d looked at the field a couple of times, and each time it was a different colour. And then he figured out what was going on. The plants had been sort of floppy, but they stood up after I sprayed them and they followed the sun. So when he looked at them in the morning they were facing one direction and when he looked at them later on they were facing another. They followed the sun through the day.



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