COCOQUBEGuide
Low EC and high EC coco peat: what buyers should compare
Electrical conductivity (EC) is the number most buyers use to talk about soluble salts in coco peat, also written cocopeat. It is useful, but only when the test method, extraction ratio, units, sampling and product condition are known. Two suppliers can report very different-looking values for similar material simply because their methods differ.
What EC tells you, and what it does not
EC measures how well a water extract of the material conducts electricity, which rises with dissolved salts. In coco peat the salts of interest typically include potassium, sodium and chloride, which can be present in raw coir. A lower EC generally points to material that has been washed or flushed more thoroughly. It does not tell you about particle structure, water and air behaviour, pH, or whether the block will perform in your crop and irrigation system.
Check the units first
EC is reported in several units, and mixing them up is a common source of error.
| Unit | Relationship | Example |
|---|---|---|
| mS/cm (millisiemens per cm) | Base unit for this guide | 0.7 mS/cm |
| dS/m (decisiemens per metre) | Numerically identical to mS/cm | 0.7 dS/m |
| µS/cm (microsiemens per cm) | 1 mS/cm = 1,000 µS/cm | 700 µS/cm |
A figure written as 700 mS/cm would be 1,000 times higher than 700 µS/cm. If a datasheet looks implausible, ask the supplier to confirm the unit in writing rather than assuming a correction.
The test method changes the number
The same material gives different EC readings depending on how the extract is prepared. Common approaches include a 1:1.5 volume extract, a 1:5 volume extract and a saturated paste extract. Results from one method cannot be converted reliably into another. Ask which method was used, the ratio of material to water, the water used, the temperature and whether the sample was tested as received or after drying.
Washed, unwashed and buffered are different specifications
- Unwashed (natural): not processed to reduce soluble salts. Suitable for blending, soil conditioning or downstream processing where salts are managed later.
- Washed: processed to reduce soluble salts. Often the starting point for nurseries, greenhouses and propagation.
- Buffered: a separate treatment, commonly done with a calcium-based solution, to make the material behave more predictably with feed programmes. It is not the same as washing, and producers use different processes, so ask for the treatment to be described.
Low EC does not finish the specification
A low-EC requirement should also say whether the material must be washed, buffered or both, the permitted EC range with units and method, pH expectations, physical structure (pith, chip and fibre balance), moisture basis, expansion test, packaging and intended crop. We do not assume a threshold for you. Your agronomist or your own media specification sets the acceptable range.
High EC is not automatically a defect
Natural or unwashed material can suit soil conditioning, blending, or downstream washing and buffering at your own facility. Whether a given EC is acceptable depends on the application and your process. Ask for the lot value using the agreed method before approving.
Moisture basis and sampling
EC reported on dry material and on material with its natural moisture are not the same. Agree the basis in advance. Also agree how samples are drawn, because EC can vary between blocks and between lots. A retained sample from each lot, kept by the supplier, lets both sides re-test the same material if a result is questioned.
What to put in the RFQ
| Detail | Why it matters |
|---|---|
| Target EC range and units | Defines what "low" means for you |
| Test method and extraction ratio | Makes two results comparable |
| Washed, buffered or natural | Different treatments, different behaviour |
| Moisture basis | Changes the reported value |
| Expansion test and physical structure | Pith, chip and fibre balance affects water and air |
| Crop, water quality, quantity, destination | Lets the supplier assess fit and freight |
Useful RFQ wording
“Please quote the available coco peat block format for [application]. Our target EC is [range] using [test method and units]. Confirm washing or buffering, physical structure, moisture basis, expansion method, pack configuration, quantity and destination.”
How to verify before you buy at scale
- Order a paid sample block from the grade you intend to buy.
- Send it to a laboratory you trust and ask for the method you specified.
- Compare the result with the supplier figure, using the same units.
- Run a small crop or propagation trial if the use is critical.
- Only then agree a pallet pilot.
Related reading
See the coco peat block range, the RFQ checklist, how to compare bulk block quotes and coco peat versus peat moss. Ready to ask? Use the block quote form.
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