How to Buffer Coco Peat

Buffering Coco Peat 

 

Buffering of coconut fiber is a chemical process consisting of replacing sodium and potassium with calcium, washing away excess waste.

 

The recommended buffering ratio is:

1,000 litres of water mixed with 7 kg of Calcium Nitrate will buffer 5 Cubic Meters of coco peat.

 

A very simple method is to use a bunker (wash bay) system to buffer the coco peat. It can be done in lots of 25, 50, 75, 100, 125 or 150 cubic meters at a time – depending on the size of your wash bay.

The first step is to hydrate or expand the coco peat completely. Once expanded, leave the coco peat until there is no more water runoff.

The next step is to mix Calcium Nitrate at a ratio of 7 Kilos per 1,000 litres of water.

The recommended buffering ratio is 200 litres of treated water (i.e. water mixed with Calcium Nitrate) per 1 Cubic Meter (or +/- 15 x 5kg blocks) of coco peat – alternatively: 1,000 litres of water mixed with 7 kg of Calcium Nitrate will buffer 5 Cubic Meters of coco peat. Ideally the treated water should be administered over a 24-hour period via a slow sprinkler system or irrigation system.

 

After the treated water with Calcium Nitrate has been applied, leave the hydrated coco peat heap for two days for the buffer to take full effect and for optimum results.

Once the resting period is over, rinse the coco peat once more – i.e. let the all the water runoff, fill the wash bay again with water and let it then run off once more.

You will now have buffered cocopeat.

A totally soluble Calcium Nitrate is preferred. Field grade Calcium Nitrate can also be used if the mixture is adequately agitated to dissolve the particles.

If sprinklers are not available, one can simple soak the coco peat in the treated water – just ensure that the coco peat and water are well mixed.

 

Growers are becoming aware of the importance of buffering Coco peat coco coir growing substrate. (Not all plants require buffering.)

To get the Coco Coir from the Coconut husk it goes through many stages of grading processes – ageing, washing, sometimes steaming, buffering, drying, grinding and compressing into different sizes and grades of Coco Coir, namely Fine, Coarse and different size chips. This ensures that the chemical and physical characteristics of the coco are altered to ensure the best quality Coco Coir for growing plants in.

  • Coco has an ideal ph.
  • Coco holds 22% air even when fully saturated-hydrated.
  • Coco has excellent drainage properties.
  • Coco has anti-fungicidal properties which help plants to get rid of soil-borne diseases.
  • Coco peat is 100% renewable.
  • Coco peat is easy to hydrate.
  • Coco peat is 100% Environmentally friendly.

After the treated water with Calcium Nitrate has been applied, leave the hydrated coco peat heap for two days for the buffer to take full effect and for optimum results.

Once the resting period is over, rinse the coco peat once more – i.e. let the all the water runoff, fill the wash bay again with water and let it then run off once more.

You will now have buffered cocopeat.

A totally soluble Calcium Nitrate is preferred. Field grade Calcium Nitrate can also be used if the mixture is adequately agitated to dissolve the particles.

If sprinklers are not available, one can simple soak the coco peat in the treated water – just ensure that the coco peat and water are well mixed.

 

Most Organic matter and Coco peat have naturally negative charges on its surface which attract cations (positively charged ion). The total number of cations that anything can hold onto or exchange are referred to as the Cation Exchange Capacity or CEC. CEC will help to determine the amount of nutrients that the growing media can hold onto before it starts leaching.

The CEC Cation Exchange Capacity of Coco Coir is between 40-100meq/100g (meq or milli-equivalent is used to measure the cation exchange capacity). This means that Coco can hold onto nutrients very well but it can also lock certain nutrients out leading to deficiencies in your plant.

Coconut trees have a naturally high tolerance for salt (sodium chloride) as most plantations grow along the coast. This means that the Coco’s cation exchange complex is naturally saturated with Sodium. Coco coir’s CEC also naturally contains large amount of Potassium and low amounts of Calcium and Magnesium. These 4 cations are the most important cations when buffering Coco.

Coco Coir has a salt content or Electrical Conductivity level of 2 to 6 mS/cm which is  too high for a growing medium.

High quality Coco Coir should be washed thoroughly until an E.C of below 1mS/cm is reached. After washing, there will still be Sodium and Potassium in the complex of the Coco Coir which can only be removed through buffering.

There is a big difference between Washing and buffering Coco. 

Washing the Coco Coir will allow the water-soluble elements to be removed but buffering will remove elements that are naturally bonded to the cation exchange complex of Coco peat.

The goal is to lower the amount of CEC Cation Exchange Capacity sites that have Potassium and Magnesium attached. Potassium can be attached to up to 40% of the sites and Sodium can be attached by up to 15% of the sites. This is important as if 40% of the exchange is holding Potassium that means that there is 40meq/100g of media of Potassium which is a single-charge molecule. Hydrated Coco Coir should make 12-15L of medium per 1kg of dry, compressed Coco Coir. This would mean that there is as much as 1.56g of Potassium per 100g of media.

 

 

Buffering is important for growers who have a recirculating system-irrigation system as it gives them more control over how much Calcium your plants are getting and prevents a build-up of salts.

When buffering your Coco Coir, you are exposing the cation exchange to a solution that contains high concentration levels of the cations we do want on the sites, being Calcium and Magnesium. Cations that are already bonded to sites are quite difficult to remove and therefore a simple washing of your Coco Coir won’t do much to change the makeup of the undesired cations. Washing will only change the E.C but not the CEC Cation Exchange Capacity of the Coco.

Sodium, Magnesium, Potassium and Calcium will all be absorbed at different rates even if they were all introduced into a solution at the same concentrations. Calcium and Magnesium are absorbed at double the rate due to them having a double-positive charge while Potassium and Sodium have a single-positive charge (Ca++ , Mg++ , K+ , Na+ ). Buffering products that have high levels of Calcium and Magnesium have a slower buffering rate but they help to effectively create a lower Potassium and Sodium percentage on the exchange and offer beneficial Magnesium to the CEC. This ensures that any nutrient mixes you use are going directly to the plant instead of amending the Coco’s CEC.

Nutrient Lockout and Plant Deficiencies

Using Coco that has not been buffered is going to create a very unsuitable grow medium for any plant. The positively charged cations such as Calcium and Magnesium are going to have a stronger attraction to the Coco complex where it will become unavailable to the plants and nutrient lockout will occur. This will cause Potassium and Sodium, which are less attached to the complex, to be displaced into the solution and be taken up by the plants instead of Calcium.

Calcium is crucial for a plant’s growth and is involved in almost every aspect of a plant’s development. 

Most Coco Coir on the market these days is washed but it may not be nutrient buffered so please make sure you know exactly what your buying.

ASK for a specification laboratory analysis sheet.

 

The Projar Group consists of several companies in the green sector. You can find information about products and solutions for plant producers and landscaping companies. We are a group of companies that can summarise your activities: manufacture of substrates, distribution of horticultural products and gardening and environmental restoration, and environmental services and advanced solutions. We have factories substrates in Spain, India and Sri Lanka.

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