Coconut Husk As a Growing Medium
The husking of coconuts produces multiple byproducts for gardening, including chips, dust and fiber. The fibrous part of the husk, known as coir, lends itself to the creation of a growing medium that – though it was used by ancient farmers – came to the attention of modern green thumbs in the 1980s. Gardeners turn to this alternative medium for its eco-friendly properties, impressive water retention and reusability.
As a growing medium, coir chiefly serves as an alternative to rockwool, clay balls or peat moss in soil-less media. Typically, growers use coco coir, mixed with perlite at a half-and-half ratio, in hydroponic gardening. In this situation, emitters or pumps circulate water through individual planting sites, which generally require less growing media – usually peat moss in the United States – than plants grown in soil. Mixes containing coir, perlite and worm castings, or coir and compost also serve as alternatives to potting soil.
Coconut coir lends itself to hydroponic growing in particular, as it features a high cation exchange capacity, a measurement of media-to-root nutritional transfer. Fibrous coir does not compact easily, which leaves space for healthy root systems and promotes a strong aerobic rhizosphere for nutrient and water uptake. According to “Rosebud” Magazine, even fully saturated coir retains 20 percent of its air capacity. The same source reports that the medium’s natural hormones promote root growth and root protection. Coir’s high lignin content makes the medium well-suited for reuse, as it accommodates micro-organisms that inhibit decay. In terms of eco-friendliness, coir is an organic and completely renewable resource.
A controlled study conducted in 2002 reports that growing media composed of more than 50 percent coir caused reduced growth compared to purely peat media. Additionally, a Utah State University study concludes that “no brand [of coir] [performs] better than sphagnum peat.” This medium responds best to nutrient solutions; an excess of plain water may cause the coir to become chemically imbalanced. Although coconut coir is reusable, it still requires the addition of about 10 to 20 percent fresh perlite when reused for the third or fourth time.
Coir has a natural pH of about 6; liming materials increase the pH above ideal levels for most plants. “Buffered” coco coir, the type sold in most garden centers, serves best as a growing medium, as the chemical buffering process helps balance the substance’s calcium and magnesium content. Similarly, the addition of gypsum helps the medium overcome its low calcium and sulfur content.
Coconut Husk As a Growing Medium. The husking of coconuts produces multiple byproducts for gardening, including chips, dust and fiber. The fibrous part of the husk, known as coir, lends itself to the creation of a growing medium that – though it was used by ancient farmers – came to the attention of modern green …
Coconut Coir: What It Is, How To Use It, And The Best Brands To Buy
Coco coir is an increasingly popular type of hydroponic growing medium — and for good reason. There are a whole host of benefits to growing with coconut coir that you can and should take advantage of if you’re new to hydroponics.
There isn’t a good, comprehensive guide to coconut coir out there… until now. In this guide, you’ll get just about everything you need to know about coco coir: what it is, its pros and cons, and the best brands to use.
If you just want to skip to the best brands, here they are:
Recommended Nutrients for Coco
* All of these recommendations are explained in more depth below.
What is Coconut Coir?
First, we need to understand what coconut coir actually is.
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.
Almost all of the coconut coir used for hydroponics is brown coir, as it’s processed even more after initial harvesting.
How is Coco Coir Made?
To get coconut coir ready for hydroponic and gardening uses, it needs to go through extensive processing.
First, they need to remove the coir from the coconuts. 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, which will need to be flushed out by the manufacturer 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. These bales are then chopped and processed into various formats, from chips, to “croutons”, to classic ground coconut coir.
There’s a whole lot more that goes into the process of making coco coir safe and optimal for horticultural use, but we’ll get into that a bit lower in the article.
Check out this video on the post-processing from completed coir into a shippable product:
Pros and Cons to Coconut Coir
There are amazing benefits to using coconut coir in your garden. But just like any other kind of growing media, there are also some downsides to consider before you buy
Benefits of Coco Coir
Good transition from soil gardening – growing in coco coir feels like growing in soil, because the two media look so similar. You can have a completely hydroponic garden that looks almost the same as a soil garden. The only difference is instead of watering with only water, you’d water your coconut coir garden with nutrient-enriched water.
Retains moisture and provides a good environment – coco coir is one of the most effective growing media for water retention out there. It can absorb up to 10x its weight in water, meaning the roots of your plants will never get dehydrated. There’s also a lot of growing media for roots to work through, promoting healthy root development.
Environmentally safe – although I am a fan of using sphagnum peat moss in the garden, there’s no denying the environmental concerns that peat moss poses. Coconut coir doesn’t have the same problems. It can be used more than once unlike peat moss, which breaks down over time. It’s also a repurposed waste product from a renewable resource, unlike the peat bogs where we get our peat moss.
Insect-neutral – most garden pests do not enjoy settling in coconut coir, making it yet another line of defense in your integrated pest management system for your garden.
Can be less complex than “traditional hydroponics” – if growing hydroponically is new to you, coconut coir is a good first step. You can practice the basics of hydroponic gardening without having to buy or build a hydroponic system and perform all of the maintenance that it requires.
Downsides to Coco Coir
Inert – coconut coir is inert, meaning that it has no nutrients within it. It may look like soil, but it is not soil. This means you will need to add hydroponic nutrients and control the pH when using coco coir. Growing in soil isn’t too different though, as many gardeners amend their soil constantly throughout the growing season anyways.
May need additional supplementation – you may find your plants short on calcium and magnesium when using coconut coir, so supplementing with “Cal-Mag” may be necessary.
Needs rehydration – most coco coir products are shipped in dry, compressed bricks. While this saves on shipping cost, it adds labor to your growing process as you’ll need to rehydrate them before you can use them in the garden. This isn’t too hard though!
Mixes can be expensive – garden suppliers know that coco coir can be annoying to work with sometimes, so they’ve started to offer coconut coir mixes. This saves a lot of time, but is pretty expensive — and making your own mix isn’t too difficult.
Types of Coco Coir
When you buy a coconut coir product, you’re really buying three types of coconut coir: the fiber, the pith (or coconut peat), or the coco chips.
Together, they provide a powerful growing medium. Apart, they have very specific benefits. Here’s a look at what each of them are.
Coco Pith or Coco Peat
The “peat” of coconut coir, this basically looks like finely ground coconut or peat moss. It’s so small and absorbent that if you were to use coco peat as your only growing medium, you might drown out the roots of your plants. It must be aged properly to be used as a growing media, as it can let out salts that will kill your plant if you’re not careful. Choosing a coconut coir manufacturer that ages properly is thus crucial for good growing.
Coconut fiber adds air pockets into your medium. It’s not very absorbent, which is good because your growing media needs air pockets in order to provide oxygen to the root zone. Coconut fibers do break down rather quickly though, meaning the air pockets they create will also decrease over time.
Coconut chips are basically an natural type of expanded clay pellet. They’re just made from plant matter instead of clay! They are best thought of as a hybrid between coco peat and coco fiber. They’re large enough to create air pockets, but also absorb water so your plants won’t dehydrate completely.
When using coconut coir in the garden, it is vital that you use the right mixture of these three types for the best results.
How to Choose High Quality Coco Coir
The most important factors in high quality coco coir is how it is harvested, prepared, and processed. Because none of these factors are directly in your control, you have to pick suppliers that follow all of the best practices for coco coir production.
After the coir is separated from the coconuts, it’s stored in piles for a few years. This puts it at risk for pathogens due to the natural pH of coco coir. Most producers that experience this will chemically sterilize the coir so it’s ready for use in your garden. This has its risks as well — it can prematurely break down the fibers and peat.
The absolute best manufacturers of coconut coir will have an iron-grip on their product from harvest to shipping.
- Avoid situations that are conducive to pathogen growth
- Have a dedicated system to control how the coconut coir ages
- Rinse and wash the coir to flush out salts
- Create the right blend of pith, fibers, and chips
- Package and store their product correctly
If that sounds like a lot to look out for…IT IS! Fortunately, you don’t have to do any of that. All you have to do is make sure that it was done, either by asking your local garden shop about the supplier’s practices, or by reading on below where I’ve answered most of these questions for you for each type of coconut coir product I review.
The Best Coco Coir For Your Garden
Now that you have an understanding of what coco coir is, how it’s processed and made, and what to look for when buying it, you’re armed with the info you need to make a good buying decision.
We’ve tested a lot of different brands and learned a lot simply through trial and error. Here are our findings, which you can take with a grain of salt (pun intended).
Top Pick: Urban Worm Coco Coir
This coir is not only our top pick, we stand behind it enough to sell it ourselves.
Urban Worm’s coco coir is a nice, fine particulate and soaks up moisture with ease. It’s perfect not only to use as a substrate for hydroponics, but also as a bedding in your worm farm. Blend this coir into your homemade potting mixes instead of peat moss for a pH-neutral alternative.
You can pick up this coir from our Epic Gardening store.
Other Good Picks: CANNA Coco or FoxFarm Coco Loco
- Natural plant medium
- 40l expanded, 8l dry
Both CANNA and Fox Farm are top coconut coir providers.
Both of these brands are known for their quality across their entire product range. Both CANNA and FoxFarm tightly monitor the production of the coconut coir they use in their products, so you can be sure that it’s been properly aged, dried, and flushed of salts.
CANNA sells theirs in 40L expandable bricks, or 50L expanded bags. Which you choose depends on if you want to save a bit of money on shipping and have to rehydrate the medium after receiving it.
Fox Farm sells a 2cu ft. expanded bag that is my personal choice when using an expanded coconut coir medium.
Other Options for Compressed Coconut Coir Bricks
- Consists of three different types of compressed.
- Low sodium content
- Alternative to sphagnum peat moss
Many first-time growers will opt for the cheaper compressed bricks, which is totally OK as long as it is properly rehydrated and prepared before use in the garden.
If you want to go with a compressed brick and can’t find the CANNA bricks, go with the General Hydroponics CocoTek Bale. It’s 5kg and contains a decent mix of coco pith and coco fibers. You don’t need to flush too much salt out of this product either, which is fantastic for first time growers.
Other Options for Expanded Coconut Coir Bags
- B’Cuzz CocoFiber
B’Cuzz Coco 50L bags are another good option if you can’t find CANNA or Fox Farm products in your area. They have a partnership with a Sri Lankan coir producer, meaning they have full control over the production process as well. It’s another great coir option.
If You Want Coco Chips…
- Has A Near Perfect Natural Ph Level For Optimum.
- Premium Aged And Composted For 24 Months And.
- Specifically Designed With Increased Fiber Content.
Go with this 4.5kg block of coco chips, or Coco Croutons in a 28-liter bag. These are a great addition to your garden if you need to add more aeration to your growing media and want to keep it in the coco coir family.
What Nutrients Do You Need for Coconut Coir?
Because coconut coir is an inert growing media, you will need to supplement your plants with additional nutrition. Remember — this is still hydroponic growing if you are only using coconut coir.
While many people say you need coco coir-specific nutrients, this isn’t absolutely necessary. You can get away with the standard General Hydroponics Flora series, a pH testing kit, and some Calimagic calcium + magnesium supplement.
If you want to mix it up and try something more coco coir specific, there are two options for you to try. These may be good options to pair with the matching coconut coir brand you’ve purchased:
Coconut coir is an amazing growing medium for hydroponic and indoor use. Find out what it is, how it's made, and the best coco coir to use in your garden.