Technical guide
Buffered vs Unbuffered Cocopeat
A technical guide from a coir manufacturer
Low EC comes from water. Buffering is something else entirely — and the difference between them is where most confusion about coco substrate comes from.
The distinction
Low EC comes from water. Buffering is something else
Coconut coir grows in coastal soils and is often processed near the sea. The pith holds naturally high levels of sodium and potassium, and these sit on the material’s cation exchange sites — the places where a substrate temporarily holds nutrients before releasing them to roots.
Washing removes the salts that are loose in the material. It does not remove the sodium and potassium bound to those exchange sites. That distinction is the entire reason buffering exists.
If unbuffered coco goes straight into production, the bound sodium and potassium gradually swap places with calcium and magnesium from your feed. Your fertigation recipe says one thing; the root zone delivers another. Calcium and magnesium go missing, potassium appears from nowhere, and the grower spends weeks chasing a nutritional problem that came from the substrate rather than the schedule.
The process
How buffering is done
Buffering means soaking washed coco in a calcium solution — usually calcium nitrate — so that calcium displaces the sodium and potassium from the exchange sites before the material ever reaches a grower. The displaced salts are then rinsed away, and the exchange sites arrive pre-loaded with calcium instead.
The practical result is a substrate that behaves neutrally. What you feed is what the root zone receives, from the first irrigation rather than the fifth week.
A point of honesty
Buffering is a chemical treatment, and low EC is not. Washing to below 0.5 mS/cm uses water and time only. Buffering adds calcium nitrate, which is a fertiliser salt, not an organic input. Any supplier describing buffered coco as chemical-free is either confused or hoping you are.
We supply unbuffered material as standard and buffer on request, and we say which is which.
Deciding
Which should you order
Buffered
Makes sense when a nutritional wobble in the first weeks is expensive.
- Long-cycle, high-value crops — greenhouse tomato, pepper, cucumber, berries
- When you do not want to manage the transition yourself
- Automated fertigation on a fixed recipe with little room to compensate
Unbuffered
Our standard product, and what most substrate companies want.
- When you buffer in-house to your own recipe
- Short-cycle crops, and growers who steer feed actively
- Anyone who wants control over which calcium source touches their material
- Lighter to ship and cheaper
Low EC is not the same thing as buffered. This is the most common misunderstanding we encounter. A low EC figure tells you the loose salts have been washed out. It says nothing about what is still bound to the exchange sites. You can have washed low-EC coco that is entirely unbuffered — in fact that is exactly what we supply as standard.
Comparing suppliers
How to read an EC figure on any supplier’s spec sheet
Two methods are in common use and they do not return the same number for the same material. The 1:1.5 volume extract method uses one part substrate to one and a half parts water by volume. The saturated media extract method brings the substrate to saturation and draws the solution off.
Saturated media extract figures run roughly twice the 1:1.5 figure for the same sample. A buyer who measures by saturated media extract and compares against a supplier’s 1:1.5 number will conclude the material is twice as salty as it is, and reject a perfectly good consignment.
Always ask which method a figure refers to — of us and of every other supplier you evaluate. If a spec sheet quotes EC without stating a method, that on its own tells you something about how carefully it was written.
We measure by 1:1.5 volume extract and will supply the saturated media extract equivalent on request.
Questions
Buffering questions buyers ask
Washing removes the salts loose in the material and brings EC down. Buffering displaces the sodium and potassium bound to the cation exchange sites by soaking in a calcium solution. A low EC figure tells you nothing about whether the material has been buffered.
Buffered suits long-cycle high-value crops on automated fertigation with little room to compensate early. Unbuffered suits substrate companies and larger growers who buffer to their own recipe, short-cycle crops, and anyone who wants control over which calcium source touches their material. It also ships lighter and cheaper.
No. Buffering uses calcium nitrate, which is a fertiliser salt. It is standard horticultural practice, but any supplier describing buffered coco as chemical-free is either confused or hoping you are.
Usually because they are using different measurement methods. Saturated media extract returns roughly twice the 1:1.5 volume extract figure for the same material. Always ask which method a figure refers to.
Yes. We buffer on request at our facility in Peravurani, Tamil Nadu, and supply unbuffered as standard. Tell us your crop and fertigation approach and we will advise which is right, including when unbuffered is the better and cheaper answer.
Keep reading
Where to go from here
Tell us your crop and fertigation approach.
We will advise which is right — including when the answer is unbuffered and cheaper.