What is Unbuffered Coco Coir?

Buffered vs Unbuffered Coco Coir – What’s the difference?

The use of the coco coir soil less substrate has grown significantly in recent decades. With numerous options marketed to cannabis cultivators, one aspect stands out: buffered vs unbuffered. This post will illustrate the differences, benefits, and drawbacks of each. Below you’ll learn why and how to buffer coco coir!

Coco Coir – (In) a Nutshell

Coco coir is the exterior shell (typically referred to as the husk) of the coconut. Until relatively recently it was regarded as a useless byproduct of the coconut industry, was discarded, and sat unused. That is until growers realized these piles of material had several characteristics which make it an ideal substrate:

  • high cation exchange capacity (efficient use of fertilizer)
  • naturally occurring trichoderma (beneficial bacteria)
  • hydroscopic water-wicking ability (acts like a sponge)
  • easily compressed and expanded (save on shipping costs and storage space)

Properties Explained

Coco coir is the husk of the coconut shredded and graded into a workable media. In its raw form, coco has innumerable cation exchange sites that allow for calcium, magnesium and potassium ions to bind with it. Fortunately for cultivators, calcium, magnesium, and potassium then become readily available for uptake by roots. Unfortunately, sodium and chlorine can also bond to these sites.


Most coco coir comes from coastal areas and thereby have extremely high levels of NaCl. Excess Sodium (Na) and Chlorine (Cl) cations cause salt stress in plants leading to phytotoxicity and even crop loss. Most manufacturers offset this by buffering the material with calcium nitrate. This achieves two things: it purges the NaCl and adds calcium, one of the main elements necessary for plant growth. This is typically achieved by soaking massive amounts of raw coconut cost with a high EC solution of calcium nitrate. While this achieves the desired result it also leads to multiple problems. 

Consequences of the Industrial Buffering Processes

Traditional coco coir manufacturers typically soak the raw, unbuffered media in calcium nitrate for weeks, or months, at a time. The excess runoff then leaches into Indian and Indonesian water sources which many indigenous communities depend upon. Traditionally, many coco coir manufacturers allowed the NaCl to leach sustainably by leaving their coconut coir exposed for months to the seasonal rains. Unfortunately, as demand for coco coir has grown, more producers have adopted the practice of buffering in order to keep up with their production schedules. This has caused an environmental impact, a human impact, and an impact on quality of the coir itself. Long-term industrial buffering of coir degrades of the natural lignins at a microscopic level leading to a lower air-filled porosity, a reduction in the coir’s natural capillary action, and a decrease in water available to roots.

Washed vs Buffered

By comparison, the environmental impact of unbuffered coco coir production is relatively insignificant. It is either left completely unwashed, or is washed 1-5x times depending on the EC level requested by the client. While this practice is unfeasible for manufacturers sourcing their coconuts from coastal areas, Riococos network of inland coconut groves provide raw materials with negligible levels of NaCl. Any excess NaCl anions are removed through our MAXXwashed™ process (5x wash) resulting in a grower-optimized EC of ~0.3 EC. This allows our end user a maximum level of control over the nutrient composition of fertigation programs.

Evolving From Legacy Methods

The bagged coco coir cannabis growers have traditionally used is more often than not of the buffered variety. This widespread use and the word of mouth cultivation standards that came from it has led many growers to mistakenly of run too low an EC early in the vegetative stage. This can lead to diminished growth rate and an increase in labor costs for the application of corrective action. This practice is unique to the cannabis industry. Riococo has supplied unbuffered coco coir to the commercial agriculture sector for the past two decades and has helped to build the the foundation of many fertigation programs. We’re excited to bring this knowledge and experience to the cannabis industry by helping our growers to implement SOPs based on our known best practices.

How to Buffer Coco Coir

At the beginning of crop production there are some best practices to follow in order to maximize the substrate fertility for increased growth rates and yield. Compressed blocks should expanded with a 2.0 EC calcium nitrate (or bottled cal-mag) solution with the ph adjusted to 5.8. Once expanded,  prepare a vegetative solution with an EC of 2.5 – 3.0 and a pH of 5.8 (if possible, maintain a N:Ca ratio of ~1:1). This will allow the Ca+ cations to bond with the cocos cation exchange sites while still leaving plenty available for uptake by the plant roots. The vegetative solution is then flushed through the bags and the the new clones can be transplanted.

Monitoring Calcium Levels

A simple way to monitor calcium levels is by periodically collecting samples of the irrigation runoff and measuring its EC. Note that his isn’t necessarily to most accurate way to determine precise EC levels of the substrate itself. Leachate EC does, however, give a clear indicator that additional calcium nitrate (or cal-mag) may be needed in the nutrient solution. If the EC of the runoff is lower than the nutrient solution, growers should incrementally add more calcium to the solution (ie. 10% at a time) until the EC of the runoff is no longer lower.

Unbuffered Coir – The Master Growers Choice

For decades buffered coir has been used in the cannabis industry. However, the industry trajectory is moving away from this version of the product. Outmoded practices have a detrimental impact to local flora and fauna in manufacturing regions. The resulting inconsistent product has a detrimental economic impact to the end user. The unnecessary buffering process is a result of demand from legacy cannabis cultivators. While this industry evolves, marijuana growers are adapting to long-established commercial agriculture practices. As the leading manufacturer and distributor of unbuffered coco coir, Riococo is helping our ever-expanding clientele of cannabis cultivators evolve into the future.