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Understanding coco coir as a grow medium

Updated: Mar 13, 2020

bag coco coir

Do you remember seeing coconuts in movies, where people sip out of them as they casually lay there taking the sun. Well, we have some news for you. Coconuts can also be used in growing microgreens.


Coconut coir usually comes in blocks. Adding temperate filter water to the blocks causes it to expand to produce a very refined growing medium for microgreens, that you can mix with your soil. It keeps the pH value from diving too low; Coir is also great for soil structure.

coco chart

What Is Coconut Coir?

In the past, when coconuts were harvested for their delicious meat and juice, the coconut husk was considered a waste product. All of the material from the husk to the inner shell of the coconut was a discard product until people realized it had many applications in gardening and home products. Everything in between the shell and the outer coating of the coconut seed is considered coco coir. There are two types of fibers that make up coir — brown and white. Brown coir comes from mature, ripe coconuts and is a lot stronger, but less flexible. White fibers come from pre-ripe coconuts and are far more flexible, but much less strong. Most of the coconut coir used for hydroponics is brown coir, as it’s processed even more after initial harvesting.

coco coir

How Is Coconut Coir Made?

Before Coconut Coir is used it has through go through an extensive process before it is used. First, they remove the coir from the coconuts. How is this done? This is done by soaking the husks in water to loosen and soften them. This is either done in tidal waters or freshwater. If done in tidal waters, the coconut coir will take up a large amount of salt. This then prompts the manufacturer to flush out at a later stage. Then, they’re removed from the water bath and dried for over a year. After the drying process, which is quite extensive, the coir is organized into bales. The bales are then chopped and processed into various formats, from chips, to “croutons”, to classic ground coconut coir.

nft sysyem

Using Coconut Coir In Hydroponic Gardening

Coconut Coir makes transitioning from soil gardening to hydroponic gardening very easy as it handles just like regular potting soil. You can easily begin practicing a modified form hydroponic gardening with regular flower pots and grow lights. When searching be sure to choose the right type of coir for your purpose. You will find a variety of products packaged for garden, ornamental and hydroponic use.

Coconut coir prepared for hydroponic gardening has the sodium and potassium removed to provide a completely nutrient-neutral medium. This gives you complete control over the nutrient uptake of your plants. Extra special care is needed when preparing coir for use in hydroponics. While the ornamental variety is quite inexpensive, it is unsuitable for hydroponic and food production use because it might contain higher salt levels.

For hydroponic use, brown coir, the more processed fiber is preferable. It is more of an innate material that acts primarily as a support medium and presents less risk of introducing unwanted organisms to a hydroponic garden.

In the production process, salt is often introduced during the soaking phase. Some producers use fresh water and others use tidal waters. The salt must be rinsed out very thoroughly to produce a product appropriate for hydroponic usage.

The best quality of hydroponic grade coir, comes with a low salt content; however, never take any chances. Always flush the product with low EC nutrient solution in advance of using it in your hydroponic setup.

Rinse until the solution washes through clear (rather than brown or tan). Once you have clear water running through the product, test this water for both EC and pH before using the product. Amend and adjust as needed when supplying your setup with water.

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