What is Coconut Coir? Can It Be Used as a Garden Amendment

What is Coconut Coir

Coconut Coir, or coco coir, is becoming more popular as a soil-less planting media for indoor gardeners and microgreen growers. 

In the simplest terms, coir is the husk of coconuts that have been processed (shredded) into a soil-like consistency. Very similar to peat moss, in fact, sometimes coir is called coco peat. 

But can it be used directly in the outside garden as a soil amendment? 

The short answer is: Well, it depends.

I know, another of those indecisive answers.  But it does depend on your soil structure, composition, and garden goals.

coco coir block

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Let's Not Get Ahead of Ourselves

I thought using coconut coir was a no brainer, but while researching the topic, I found out the reasons to use it instead of peat moss isn't so cut in dry.

The plan for this website is to focus on the subject (based on the title) and not expand the article to encompass every topic on the subject.

Instead, a series of focused articles will be written and linked throughout the series. This way you won't have to read or skim over things you're not interested in or already know. Plus, the articles will be easier to update when new information becomes available (advantage of blogs over books).

Anatomy of a Coconut

Coconut coir is the part of the coconut between the fibrous outer covering (exocarp) and the brown smooth covering around the white meat that we eat (endocarp). 

To a botanist, coir is the mesocarp of the coconut, as shown below.

coconut layers showing location of coir

Coconut Coir is a Waste Product

As you can imagine, the fibrous coir is a waste product to those processing coconuts for the coconut water and meat.

So using it as an alternative to peat moss appears to be a good use for coir.

However, it's more complicated than that, and the reasons for this will be explained in a future article: Is Coconut Coir More Renewable, Sustainable, and Environmentally Friendly Than Peat Moss?

How the Heck Do You Pronounce Coir?

There appears to be two ways to say coir:

1. kȯi(-ə)r like saying the koi fish with an er on the end. 

2. ˈkȯr similar to core.

The first is correct, but as long as everyone knows what we're talking about I couldn't care less.

Where Does Coconut Coir Come From?

Coir obviously can be produced anywhere coconuts are grown or processed. According to Wikipedia, 90% of the annual coir production comes from India and Sri Lanka. 

India, significant a major producer also uses up to half of the coir it produces. So,  Sri Lanka is the world's largest exporter of coir fiber and fiber-based products.

How is Coco Coir Processed?

Much of the coconut coir used for growing and garden purposes is the waste product (pith) from generating fiber for use in mats and other long fiber products. 

Here's a link to a YouTube video on the whole process (~15-min long).

The piles of pith are composed for several months to allow the product to break down and enable rains to rinse salts from the pith. Some processors will actually rinse the piles with fresh water to speed up the process.

Pith earmarked for sale to major soil companies goes through a more rigorous cleaning process. After all, coir bagged by the larger corporations is sold to professional growers, and quality control is very important. 

For this reason, it's my opinion to purchase coir from these corporations as the quality standards are consistently higher.

Obviously shipping a bulky product halfway across the globe is expensive. ​

Coir is compressed into hard bales or blocks and dried to reduce shipping costs. The coir is easily reconstituted by adding water.

Below is a video I made of a small block being rehydrated. It expands at least 5 times its height in a matter of seconds.

How Coconut Coir is Sold

Coir is either sold (retail) by the block or brick and also expanded in bags. The bricks range from around a pound up to 11-pound blocks. 

Expanded coconut coir is usually sold as a mix, meaning other ingredients have been added to improve it. Though, some companies sell pure expanded coir. 

Can Coconut Coir Be Used In The Garden?

Coir can definitely be used in the garden.

It is excellent at holding water, it will improve the structure and tilth of the soil, especially if you have clay or sandy soils. 

However, coir does take a long time to decompose, some references say it takes 20 years or more to break down. I've seen documentaries where coconut fibers have lasted hundreds of years in the ground without breaking down. This is why it's good for soil structure.

Even though coconut coir is basically inert, with no plant nutrition available from the fibers and pith, it does retain moisture, and that water will contain nutrients that are available for the plants to use.

Coir is also pH balanced, unlike other soil amendments such as peat moss. Coir likes water and takes it in quickly, unlike peat moss that is basically hydrophilic until it is saturated.

But Before You Use Coir In The Garden

You might want to read these articles before you add coconut coir to your garden.

Is Coconut Coir More Renewable, Sustainable, and Environmentally Friendly Than Peat Moss?

How I Use Coir In The Garden

One aspect of permaculture is to reuse a product as much as possible. Or, to use it in multiple ways. Uni-taskers be damned. 

Here's how I use coconut coir.

Coir is a great seed starter. Several videos show seed starts grown in a coir based mix growing stronger root systems.

For that reason, I start seeds and grow microgreens in a coir based mix from Fox Farms called Coco Loco.  Don't let the Amazon price scare you, it costs me $20  for a 2 cu.ft. bag at a local hydroponics store.

Once I finish with the starts or the microgreens have been harvested, I use the coco coir mix as worm bedding and let it vermicompost.

Once the vermicompost is finished maturing, it is then added to the garden.

I get three uses out of one product where the quality improves at each stage before it's added as a garden amendment. 

I wouldn't add pure coconut coir to my garden before using it for something else. 

My Coconut Coir Picks

If you want to try some coconut coir to make a seed or potting soil mix (there are many recipes on YouTube) here are my suggestions.

The bricks are easier to ship through the mail system than the larger bulky expanded coir bags. If you want to try Fox Farms Coco Loco (my choice of all the brands), I suggest calling your nearest garden or hydroponics store to see if they carry it.

Have You Tried Coconut Coir?

What has been your experience? 

Leave us a comment or ask a question below. We'd love to hear from you.

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coconut coir in the garden

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