Cocopeat and Salt
As cocopeat comes from coconuts that grow on the seashore and become impregnated with salt, the raw material is very salty. To add to this problem, it is often stockpiled close to the ocean where it is subjected to salt laden winds and water. In addition, it is sometimes washed with seawater.
The resulting product can be very high in salt (sodium chloride). Sometimes it is treated prior to despatch but often it isn’t.
There are a number of problems associated with salt. Firstly, the components of salt, sodium and chloride, are toxic to plants in excessive amounts. Anything more than about 250ppm salt (sodium chloride) in irrigation water will reduce growth and yield. The sodium component has also been implicated in the blocking of uptake of other nutrients both major and minor. Excessive amounts of chloride may also block the uptake of nitrogen as well as being inherently toxic. In addition to these nutrient related effects, the additional salt also restricts the uptake of water.
Flush, Flush, Flush!
Before using cocopeat we strongly recommend that you follow the practices of commercial growers and treat the medium before use. The treatment is relatively simple and inexpensive. Simply use a cocopeat washprior to use. This will assist with flushing out the salts.
To use a cocopeat wash, simply add the required amount to the water you are using to expand the dry block. Leave saturated overnight then drain. Refill the container with water then drain again. The cocopeat is now ready for use. If you are short of time, you may dispense with the second soaking. The result will still be quite satisfactory.
In summary, cocopeat has characteristics of both soil and true hydroponics.
It is like soil in that:
- It is constantly changing
- It holds both water and nutrients
- It is conducive to the growth of beneficial organisms
- It is somewhat variable
- It sometimes has unwanted salts
It is like hydroponics in that:
- Its natural fertility is low (needs to be fed constantly)
- Its water holding capacity is fairly constant for constant grades (coarse, fine, etc.)
- Its air filled porosity is high (plenty of oxygen at the roots)
Cocopeat is well worth consideration when a grower is either starting out or contemplating a change of system.