Technical specifications

Who is this document for?

These technical specifications apply to any person or organisation wishing to produce brushwood compost in accordance with Jean Pain's recommendations — whether for personal garden use, for production for sale, or for commercialisation under a label. They define the minimum technical criteria to be met for the product to conform to the method and the principles on which it rests.

Compliance with these specifications determines the agronomic quality of the compost produced. In particular, chip granulometry and fermentation conditions are the two critical points where no compromise should be made — they determine whether soil microbiology will be correctly nourished, or not.

Raw materials & harvesting

1 Diversity of species

Harvesting of a variety of plants — maximum 80% of any single species.

2 Processing while green

Plants processed while still green (freshly cut), no delay between cutting and fermentation other than the time required for chipping and transport.

3 No maximum diameter

No maximum diameter for the plants, provided they are processed continuously — from the largest section through to the tips of the leaves.

4 Granulometry — the critical criterion

Chipping to the appropriate granulometry before the start of fermentation. No re-chipping during or after fermentation. No screening.

• Maximum thickness of the largest chips: 4 mm
• Optimal thickness: 2 to 3 mm

Wetting

5 Immediate wetting

Wetting immediately after chipping.

6 Water volume

Absorption of approximately 700 litres of water per m³ of chips (highly variable depending on the initial moisture content of the plants).

7 Relative moisture content

Relative moisture content after wetting: approximately 82%, dropping to 60% at the time of use.

8 Water quality

Any water not contaminated by hazardous elements or elements likely to interfere with fermentation. Well water preferred. No "leaching" of the chipped material. No dry fermentation. No additives of any kind other than water.

Fermentation

9 Minimum heap volume

Volume sufficient to allow a normal temperature rise (50 °C to 70 °C). This volume is estimated at approximately 20 m³.

10 Maximum height at construction

3 metres maximum.

11 Maximum volume per heap

300 m³ maximum per heap.

12 Fermentation temperature

Throughout the fermentation period, temperature must be self-maintained between 45 °C and 80 °C.

13 Turning — mandatory

Turning and re-fermentation approximately 2 months before use or bagging, to homogenise the whole heap (possible dry pockets). Loading into a trailer for transport (in the case of large-quantity transport) may be considered to constitute turning.

14 Minimum fermentation duration

Use after a minimum of 6 to 8 months of non-strict aerobic fermentation. Surface application only — no soil incorporation. Relative moisture content at the time of use: 50% to 60%.

Heap composition