Coconut Coir: What Is It and How To Use It

coconut coir
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You may have heard of coconut coir, but do you truly understand it? This remarkable natural, sustainable product, once a neglected byproduct of the coconut industry, is now, rightfully, growing in popularity.

In case you haven’t guessed already, I love coconut coir. It’s my favorite growing medium, as it means I don’t have to contribute to the decimation of irreplaceable habitat and environmental savagery or stay true to my holistic lifestyle but have to settle for an inferior growing medium. 

The meat and water were the prize during coconut harvesting, while the husk was historically left to rot. Thankfully, now, we recognize this resource’s value and use the whole husk, from the shell to the outer coating or the coir, in terms of a fantastic, sustainable growing medium.

The Journey From Coconut to Coir

coconut husk planter
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Transforming coconut husks into useful coir is more complex than scooping out the meat and coconut water (I adore coconut water – yum!). It starts with soaking the husks in saltwater or freshwater to soften them, preparing them for further processing.

If soaked in seawater, they absorb salt, which requires additional processing later on to remove it. The husks are left to dry for over a year. Next comes chopping and processing, turning the husks into different types of coir (more on that below).

Types of Coco Coir

Coco coir is available in three primary forms:

Coco Pith or Coco Peat

Resembling finely ground coconut or peat moss, coco pith is highly absorbent. It’s best used as a component in potting mixes or soil conditioners rather than as a standalone medium.

I like to use coco pith instead of vermiculite or pearlite in mixes where I need good water retention. 

Coco Fiber

After extensive drying, the long fibers from the husks are ready for use. They improve porosity and drainage in garden soils and potting mixes. 

Coco fiber also frequently ends up in my homemade soil mixes, as, while the coco pith is excellent for retaining moisture, the coco fiber provides good soil structure and drainage, so the plants don’t get waterlogged. The soil doesn’t get overly compacted.

Coco Chips

Coco chips are the middle ground between pith and fiber. They help create air pockets in the growing medium while retaining moisture. If you’re only going to invest in a single type, particularly for seed starting, I’d go with coco chips, as they’re a stable blend with the correct ratio of pith to fiber. It’s a good choice if you don’t want to make your own blend. 

Advantages of Using Coconut Coir in Your Garden

I can’t sing the praises of Coco Coir enough. You can use it in the greenhouse, in hydroponic setups, in your garden beds, and for house plants. It’s so versatile. As a green freak, I love that it’s sustainable, renewable, recyclable, and reusable.

Water Retention

It holds up to 10 times its weight in water, retaining moisture ready for your plant roots to take up. A ready water supply is essential for healthy plants, as it impacts growth, nutrient uptake and distribution, and the stability and structure of plant cells. 

Resistance To Bad Things

Interestingly, coconut coir is also antifungal, helping keep fungal pathogens at bay, which is particularly important for seedlings and plants in warm, humid environments and areas prone to fungal issues. 

It’s also resistant to mold and certain diseases, giving your plants a fighting chance at healthy, infection-free growth.

Effects on Soil

Coconut coir has a neutral pH, so it’s safe for all plants and won’t adversely affect the pH of your soil. And, with the inclusion of coco fibers, coir improves soil structure, helping to aerate the soil and improve drainage while being hydrophilic enough to retain moisture without overwhelming your plants’ roots. 

Aeration and good structure are critical to soil health, as without adequate air in the soil, your plants and the good bacteria and organisms will die. The improved soil structure encourages deep, strong root growth, boosting overall plant health and reducing reliance on surface watering. 

Environmental Considerations

One of the best things about coco coir is its minimal negative environmental impact–assuming it’s grown, harvested, and processed sustainably. 

Coco coir is sustainable, renewable, reusable, and recyclable. Coco coir is renewable, unlike peat moss, which takes hundreds of years to replenish. It’s a byproduct of coconut farming, so putting it to use in your garden is a great way to use a waste product that would otherwise be left to rot. 

Unlike peat moss, which isn’t structurally strong enough to be reused, coco coir holds its structure well until it decomposes so you can use it over and over again, and it takes a while to break down, so you won’t have to add it to the garden beds every year. It also makes excellent brown matter in your compost heap, speeding up the composting process by aerating the pile for the bacteria to thrive.

Considerations When Using Coconut Coir

One significant point to note is that coco coir is inert, so in its pure form, it has no nutrients. Therefore, you can’t just take a bunch of coco coir and dump your plants in it. You’ll need to add nutrients to it if you’re using it for seedlings and container plants.

In my opinion, the easiest way is to add some beautiful, rich compost, preferably organic stuff, from your compost heap. But you can also use an excellent, high-quality compost from the store. You can also add worm castings or well-rotted manure. 

Whichever option I choose, if I’m transplanting, potting on, or trying to get a plant established or it needs a boost, I like to add some of my homemade willow water, a powerful DIY rooting hormone that encourages rapid, strong root growth that has plenty of plant health benefits of its own.

And pay attention to where your coco coir comes from and how it’s been processed. I buy mine from a company that uses sustainable practices and organic principles. And they process their coconut husks in fresh water, not salt. 

If you go for a brand that soaks the husks in salt water, be careful as, if they don’t rinse it thoroughly, the coco coir will have an intolerably high salt content that can cause long-term harm to your soil, and you’ll struggle to grow pretty much anything. 

Application in Gardening: A Versatile Medium

Coco coir can revolutionize how you garden. It’s excellent for soilless potting mixes, enhancing drainage and aeration. But in this case, you’ll need to provide a steady supply of nutrients, like the liquid hydroponic products. 

In your garden, it improves the texture of both clay and sandy soils, giving the soil a better structure that retains moisture but allows adequate airflow and drainage. 

Indoor Plants

For indoor plants, especially those in hydroponic setups, coco coir provides a stable, supportive environment. Its slow decomposition rate and moisture retention qualities make it a good choice for most plants​.

I like it mixed with high-quality organic compost for starting seeds and nurturing seedlings in the greenhouse because of its good structure and antifungal and anti-mold properties. I find it particularly useful for growing delicate seedlings like peppers that are prone to mold and fungus. 

Outdoors

Because of its slow decomposition rate, I am a huge fan of using coco coir with plants that stay in situ for several years. Strawberries are a great example. 

Whether growing brand new strawberry plants from scraps or bringing on maiden strawberry runners, I like to establish them using my coco coir seed starting blend. Then, when I’m ready to plant them out in their final position, I dig in plenty of coco coir right into the soil of the new strawberry patch, along with a good dose of well-rotted manure or compost.

I plant the strawberries in this mix, then mulch them with a top dressing of coco chips. The coir I dug in provides excellent structure and a good moisture balance, encourages healthy root growth, and helps limit the risk of certain soil fungi and pathogens. The top dressing retains moisture, inhibits fungus and mold, and helps to keep the ripening fruit off the wet ground. 

And this setup will last four years with minimal intervention from me. Four years is the approximate duration for peak strawberry production. After this, it’s time to get rid of the old plants anyway. 

How To Use Coconut Coir

Using coconut coir in your garden is straightforward and can significantly benefit your plants. Here’s a simple guide to help you get started:

Break the coir

Coconut coir block
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The block of coco coir may be too much for your pot. Break it into the amount you need. Take note that as the fibers absorb water, the volume expands.

Rehydrate the Coir

coco coir - soaking
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Coconut coir often comes in dehydrated bricks. Soak the brick in a container of water until it expands. This usually takes about 15–30 minutes. Once it’s rehydrated, fluff it up to a soil-like consistency​.

Mix with Soil

coco coir - mix with soil
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You can improve your garden soil by mixing coconut coir. Coir enhances drainage and aeration for clay soils while increasing water retention in sandy soils. A mix of long-fiber coconut coir with coco peat or other substrates is ideal for aerating compacted soil, promoting healthy root growth​.

Use in Potting Mixes

Combine coconut coir with other potting mix components like nutrient-rich super-fine compost. This creates an ideal environment for plant roots, balancing moisture retention, drainage, and aeration​.

Adjust Nutrients and pH

Since coconut coir is nutrient-poor and inert, you’ll need to add nutrients, either in the form of hydroponic nutrients or high-quality compost and worm castings. You may want to adjust the pH for optimal plant growth. 

Monitor Watering

monitor watering
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Be cautious with watering due to its high water retention capacity. Overwatering can be an issue, especially in plants that prefer drier conditions. Adjust your watering schedule accordingly to avoid waterlogging.

You can also use coco fiber wrapped around a pole to support your houseplants in place of a peat moss pole. You can create a potting mix for houseplants, including succulents, using a blend of coco coir, compost, and other components.

This article originally appeared on Wealth of Geeks