Coir price volatility and peat import restrictions have pushed Southeast Asian nurseries to rebuild their mixes, and the first thing that breaks is cation exchange capacity. A straight coir-perlite mix has almost no ability to hold calcium and magnesium, so the nursery compensates with extra feeding, the EC in the plug tray climbs, and the seedlings go into the field with a root system shaped by salt stress. A 150 mesh humic powder at 3-6 kg per cubic metre puts exchange capacity back into the mix without changing the physical structure.
The fine mesh matters at this scale. A 60 to 100 mesh powder in a 128-cell tray does not distribute evenly, and the coarse particles sit on the surface where they do nothing. At 150 mesh, the powder disperses through the mixer in one pass and coats the coir fibre, which is exactly where you want the exchange sites. Mixers we have worked with in Malaysia and Java report 8-15% higher water holding at 5 kg per cubic metre, which translates directly into one fewer irrigation cycle per day in the nursery.
The other benefit is buffering. Coir is naturally high in potassium and sodium, and young seedlings are sensitive to both. The humic fraction adsorbs part of that load in the first weeks, which is when the tray is most vulnerable. Nurseries using it in their standard mix usually reduce the initial fertigation EC from 1.8 to around 1.4 dS/m, and the seedlings are not softer for it, they are more uniform.
Key Features
- 150 mesh fine powder: Disperses evenly through a ribbon or paddle mixer in one pass, no coarse particle segregation in the tray
- 3-6 kg per cubic metre dose: Low inclusion rate, so the cost per cubic metre of finished mix stays predictable
- Restores exchange capacity in coir: Adds the CEC that a straight coir-perlite mix lacks, holding calcium and magnesium near the root
- Buffers coir potassium and sodium: Reduces early seedling stress in fresh coir that has not been properly aged
- 8-15% water holding gain: Measured at 5 kg per cubic metre in coir-based mixes, which removes roughly one irrigation cycle per day
- Peat reduction support: Allows a lower peat share in the mix without losing the cation behaviour peat was providing
Technical Specifications
| Parameter | Specification |
|---|
| Appearance | Black fine powder |
| Humic Acid (dry basis) | 60% min |
| Organic Matter | 75% min |
| Particle Size | 150 mesh, 95% pass |
| Moisture | 10% max |
| pH (1% suspension) | 7.5-9.0 |
| Dosage in substrate | 3-6 kg per cubic metre |
| Water Holding Gain | 8-15% at 5 kg/m3 in coir-based mixes |
Applications
Blend 3-6 kg per cubic metre of substrate at mixing, before wetting. For coir-heavy mixes use the upper end. For vegetable plug production, 3-4 kg per cubic metre is normally enough; for tree seedlings in larger bags, 5-6 kg. Also used as a drench at 2-3 g per litre on established nursery stock every two weeks.
Do not blend into a mix that already carries a high humic load from compost; the total organic carbon can push the mix past what a small plug can buffer, and nitrogen tie-up follows. Test the first batch on 200 trays before committing a full run.
Packaging, Documentation & Quality Assurance
Packed in 25kg multiwall paper bags with PE liner, 40 bags per pallet, and 500kg jumbo bags for media producers. Neutral bags or private label printing with your mix instructions on the back panel is available.
Each lot is tested for humic acid, organic matter, mesh, moisture and pH, with a quarterly heavy metal composite for media producers who supply supermarket programmes. Retained samples are kept 24 months. Pre-shipment samples with the matching lot code can be couriered so your media laboratory can run its own water holding and EC test before the container is loaded.
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