Buffered vs Unbuffered Cocopeat

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, and it is where most confusion about coco substrate comes from.

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.

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.

An important 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. Calcium nitrate 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.

Buffered makes sense when you are growing a long-cycle, high-value crop where a nutritional wobble in the first weeks is expensive — greenhouse tomato, pepper, cucumber, berries. It also makes sense when you do not want to manage the transition yourself, or when your fertigation is automated to a fixed recipe with little room to compensate.

Unbuffered makes sense when you buffer in-house to your own recipe, as many substrate companies and larger growers do. It also suits short-cycle crops, growers who steer feed actively and can compensate in the first weeks, and any buyer who wants to control exactly which calcium source touches their material. Unbuffered is lighter to ship and cheaper, and gives you full control.

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.

Two methods are in common use and they do not return the same number for the same material:

• 1:1.5 volume extract — one part substrate to one and a half parts water by volume
• Saturated media extract (SME) — the substrate is brought to saturation and the solution drawn off

SME figures run roughly twice the 1:1.5 figure for the same sample. A buyer who measures by SME 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 SME equivalent on request. Our testing and batch reporting is described on the quality page.

We supply washed low-EC cocopeat unbuffered as standard, and buffered on request.

Buffering questions buyers ask

Our products: Coco grow bags · 5 kg blocks · Coco chips · 600 g bricks · Cocopeat

Crop guidance: Tomato · Strawberry · Cucumber · Capsicum · Blueberry

Tell us your crop and fertigation approach and we will advise which is right — including when the answer is unbuffered and cheaper.