coco coirs slabs

מצעי גידול

Advantages of Coco Coir

Occasionally I get onto websites and discuss coir with novice growers. The way I explain it to them is that coir represents the best of soil and hydro in a single media.
While this is a simplistic method of describing coirs unique properties, it is also an effective way to help growers understand the media’s natural buffering qualities, natural root zone preservation qualities and the ability to provide optimized nutrition via hydroponic technologies. To me, this makes coir the ideal media for novices who often
grow in less than ideal environments. That is, coco coir, more so than any other media
is extremely forgiving

 

PH Buffering

Coco coir buffers at between pH 5.5 and 6.5. This means the media helps to maintain
optimum root zone pH – resulting in optimum nutrient uptake

 

Cation Exchange Capacity

Coir has a high cation exchange capacity. Cation exchange capacity refers to a Medias ability to exchange cations between mineral and organic matter and the plants roots. Cations are positively charged elements such as calcium (Ca++), magnesium (Mg++), and potassium (K+). Cations are held by negatively charged particles called colloids. The defining feature of colloids is that the particles are small and consequently the total surface area is huge. For this reason the negatively charged colloids are capable of holding enormous quantities of positively charged cations. As plant roots uptake cations, other cations in the nutrient replace them on the colloid. If there is a concentration of one particular cation in the media, other cations will force them off the colloid and take their place. This means that a mineral balance is maintained in coir and these minerals are readily available for uptake

Root Zone Health

Coco coir provides excellent insulation. This means that coco coir isn’t as prone to overheating, due to excessive ambient air temperatures, as many other mediums (making it ideal for warm geographical zones). This is because water tends to make its way into the lower regions of the coco coir, leaving the top layer dry. Because of this, heat needs to penetrate a drier top layer of coco coir before reaching the watered areas of the media. As water is a great conductor of energy (in the form of heat) the lower wet area being protected by a drier surface helps keep the lower areas of the media, where the bulk of the root mass is found, cooler. As media temperature and oxygen levels are interrelated (the warmer the media, the less oxygen) this insulation plays an important role in promoting root health Compare coco coir to Rockwool, another run–to-waste media. There are some significant differences in moisture distribution and media insulation qualities. Rockwool tends to become evenly saturated. Water, thus, distributes evenly from top to bottom, leaving the Rockwool, typically, very damp. This means that heat can travel throughout the media (dry Rockwool is an excellent insulator; it is simply that water conducts heat). When the ambient air temperature is excessively warm, so too is the media. Depending on the extent of this problem (too warm – not enough oxygen), oxygen availability to the root zone can become dangerously low. As I’ve already pointed out, coco coir tends not to do this. Water displaces from the surface of the media and moves into the lower regions. Because of this the media generally remains significantly cooler around the root zone of the plant. Secondly, coco coir contains natural rooting compounds, in the form of potassium (electrolytes) and phosphorous (enzyme function/sugar production). Both potassium and phosphorous stimulate root growth and development. Thirdly, coco coir has excellent air filled ‘porosity’ – the term used for the levels of oxygen availability (critical for transpiration) in the media. This is due to the large surface area of coco coir particles. As oxygen plays an all-important role in respiration (roots pumping nutrient to the plant) this factor further promotes root and (hence) plant health. What all of these factors add up to is that coco coir provides a sound environment for the plant’s root zone. This factor should not be underestimated because healthy roots invariably lead to a healthy plant (and a healthy yield).

 

The Fundamentals of Coir

The coconut palm, unlike many other plants’, is a salt tolerant plant. What happens with salt tolerant plants’ is that they uptake salt and displace it to areas of the plant where the salt can do the least harm. In the case of the coconut palm the salt is displaced to the coir – the very thing that we use as a growing media. This means coir can contain high levels of salt (sodium chloride), something which can prove toxic to many/most plants. On top of this coir contains large amounts of potassium and quantities of other elements. What this means is that coir requires special treatment to
ensure a premium quality hydroponic media product is supplied to the end

 

Source of Material
Coir derived from palms that are grown 50kms inland will have far less sodium chloride present than coir that is derived from palms that are grown close to the sea. That is, less sodium chloride present in the soil results in less sodium chloride in the coir. The origin of the coir is an important factor in determining the quality of the end product

Flushing and Buffering
In order to prepare the raw coir product for use it is necessary to flush plentiful mounts of water through the product to wash out impurities (including sodium chloride). Premium grade coir is then buffered with various elements to prepare the coir for use. This requires flushing the coir with mineral elements in order to compensate for tentially problematic levels of sodium chloride and potassium (and other elements where required). For instance, Iron is sometimes used to offset sodium chloride while magnesium and calcium is used to compensate for the naturally present, often high levels of potassium and phosphorous (While potassium and phosphorous are naturally by plants and are beneficial elements, extreme levels of these elements can result in imbalanced nutrition and mineral element lockout). Typically, most suppliers of hydrated coir only flush the media and do not buffer it. This can prove detrimental to plant vigor and health, particularly in early growth. Some Symptoms of toxicity include the following:

  • Rusting – particularly on leaf edges
  • Yellowing
  • Slow stunted growth
  • Mineral deficiencies
  • Purpling of stem

Treatment/Age of Raw Product

Coco coir has a shelf life where optimum performance is concerned (due to organic decomposition factors). Ideally the raw coir used in hydroponic Medias should be less than two years old. Older coir is difficult to manage and will not last as long as newer coir.

Tips for using Coco Coir

Run-to-waste regime
after many years of experimenting in coir, both in indoor and outdoor settings, with various crops I have found that running a 25% – 30% waste regime is the most user friendly means of growing in coir. The 25 – 30% waste regime ensures that salt buildup in the media is kept to a minimum, and means flushing is typically never enquired; the agricultural standard being a 30% waste regime with the runoff being no more than 0.4EC higher than the original nutrient feed. EC can be tested in the runoff and be compared to the nutrient EC

Air Porosity
typically, the bagged (hydrated) coir products sold via hydroponic outlets consists of fine particles and coir dust. While this means excellent fluid retention, it also means less than ideal air porosity in the media. Adding Perlite to the media will increase air porosity. A 60% coir to 40% Perlite mix being ideal (50/50 is also OK). Another means of increasing air porosity is by mixing larger coir particles into the coir fines/dust, thus lifting the media and achieving a similar effect to a coir/perlite mix

PH
Ideally, the nutrient should be maintained at between 6.1 (grow) and 6.3 (bloom). PH cannot be measured in the runoff. I.e. The runoff does not accurately reflect what is happening within the coir where pH is concerned. To test the pH of coir, take a sample of the coir from the root zone and add 1 part of coir to 5 parts of distilled water, shake and measure pH