Coco coir is a fairly new addition to the gardening world that has many growers excited about its potential. It’s a versatile, soilless growing medium with lots of applications out in your garden and for hydroponics.
Lots of gardeners are concerned about making their gardens as eco-friendly as possible, and using coco coir fits right in with this mission.
Here’s a guide to exactly what coco coir is, its benefits, and why you would want to grow using it.
What is Coco Coir?
Coco coir is short for coconut coir and is sourced- you guessed it- from coconuts. It comes from the husks of coconuts, the inner part between the hard outer shell and the flesh in the middle.
Coconut husks are made up of fibrous but very tough and dense material. These durable fibers have been used for things like making rope and rugs in Asian nations for many years but have mainly been considered a waste product of coconut processing in most of the rest of the world.
More recently, better methods for extracting and processing coco coir have been developed and its many uses in the garden were discovered.
Coco coir comes from the husk of coconuts. The fiber has been used for thousands of years in countries where coconuts grow but only recently has been made available on a large scale to the rest of the world.
How Coco Coir is Made
Coconuts go through a long process to get to the end product of coco coir.
First, the husks have to be separated from the flesh and milk that are used as food products. The fibers of the husk then need to be softened and detached from the outer shell.
This can be done by mechanical means or by soaking the husks in either freshwater or saltwater (the more traditional method). The fibers are naturally resistant to breaking down in saltwater but can retain high levels of salt afterwards.
After the softening process, the fibers are detached from the shells and dried.
Depending on the processor, the coco coir might be sanitized with chemicals or steam to get rid of any pathogens. It’s eventually formed into bales that can be chopped up and packaged in a variety of ways for sale.
Types of Coconut Coir
You’ll often see products labeled simply as “coco coir” or “coconut coir.” These usually contain all the components of the fiber harvested from the husks.
There are several different types of processed coco coir available if you enjoy making your own mixes. The pith is the spongy part of the husk and resembles ground peat moss.
However, there are also more processed products available that separate out the different types of coir for specific uses. Here’s a look at the main ones:
- Fibers– The long strings of coconut fiber can be separated from the rest of the coir and used on their own. They add a lot of oxygen pockets and aeration to growing mixes and soil but break down fairly quickly. Fiber is popular as a hanging basket liner.
- Pith or peat– Coco pith (also called peat) is more spongy in nature and looks like finely ground peat moss. It’s very much the opposite of the fibers because it retains a lot of water but doesn’t provide much aeration.
- Chips– Coco chips are small to medium chunks that can both hold water and provide aeration to soil. They can be used for growing and as bedding for small reptiles and animals.
If you find that you like working with coco coir and enjoy making your own mixes, you can choose to buy these different types of coir and make your own mixture.
Otherwise, you can buy the already mixed version, which usually comes in one of two forms:
- Block– This is completely dried and shrunk coconut coir that is compressed into relatively small bricks. You have to add water to the bricks in order to use them, and this will cause the coco coir to expand well beyond its original size. It can be slightly labor intensive to get the coir wet enough to work with, but you can get a lot of it out of one block.
- Loose– The loose version comes in a bag like soil or peat moss. It has already been rehydrated and is ready to use. Working with loose coco coir is as easy as taking it out of the bag, but it costs more than the block form because of the additional steps to rehydrate it and make it ready for use.
Pros and Cons of Coco Coir
Now that you know what coco coir is, why would you want to use it for gardening? Here’s a look at the main benefits as well as a few drawbacks of coconut coir for garden use.
- Water retention– Similar to peat moss, coco coir is good at holding onto water and can retain it at 7 to 10 times its own weight. This means that it releases water to plant roots as they need, so even though it can absorb a lot of water, it won’t drown your plants.
- Holds nutrients– Just like with water, coir will hold onto nutrients and keep them from leaching out of your soil. This keeps them available to your plants with the exception of a few specific nutrients (see drawbacks section below).
- Aeration– Coconut fibers are very porous and will help to improve the aeration in both soil and other growing mediums. This helps with drainage and also provides plant roots with the oxygen they need.
- Neutral pH– The pH of coco coir is usually in the range of 6.0 to 6.8, which is a fairly neutral pH. This means it won’t cause a dramatic shift in pH when added to soil.
Coir is especially good for growing because it helps soil retain water and nutrients while still providing good aeration and drainage. It also has a neutral pH, which is good for many types of plants.
- Repels pathogens and pests– Coconut fibers are naturally resistant to pathogens that cause rot and other fungal problems. It’s also free of weed seeds and fungus gnat eggs that can show up in soil based growing mixes. Depending on how it was processed, some coco coir is sterile, which means you won’t have to worry about bacteria.
- Reusable and biodegradable– Unlike most growing mediums used in gardening, coconut coir can actually be reused when it’s processed properly. If you don’t want to reuse it, it will break down in your soil more slowly than peat moss and organic materials, keeping its texture for longer.
- Eco-friendly and sustainable– Coco coir is considered a very eco-friendly product because it’s sourced from the parts of coconuts that used to go to waste. Coconut trees are constantly growing new coconuts, making the fiber a very renewable resource.
- May be high in salt– Depending on how it was processed, coconut fiber can have a high amount of salt leftover from soaking in saltwater that might be harmful for your plants. Many manufacturers will rinse this off before it gets packaged and sold, but it’s something you’ll need to check into.
- May contain chemicals– In order to kill off pathogens at the end of the drying process, some producers will treat coco bales with chemicals. You may need to do a little searching to find untreated coir that’s suitable for organic gardening, but it’s out there.
Coconuts are still often processed in saltwater to soften up the tough fibers before they are extracted. This can leave excessive amounts of salt in the finished product if not rinsed out.
- No nutrients– Even though coconut fiber can hold onto nutrients for you plants, it contains little to no fertility of its own. This means you’ll need to add fertilizer and nutrients in some other way. Liquid plant feeds are an easy way to do this.
- Locks out certain nutrients– Coco coir tends to hold onto calcium, magnesium, and iron rather than releasing them to plant roots. Some manufacturers adjust for this in their mixes, but you may need to add more of these specific nutrients to make sure your plants get enough.
- Expense– For home use, the expense of using coir will be affordable for most people, but if you do a lot of gardening or have some big garden projects on the table, it can get expensive rather quickly.
Ways to Grow Using Coconut Coir
Now that you know about all of the benefits of coconut coir, here are some ways to try using it for gardening.
Soilless Seed Starting Mix
Most seed starting mixes are soilless, which means they don’t have any actual dirt, compost, etc. in them. This is because of bacteria and other pathogens that are often present in soil and might kill your seedlings.
To prevent this, many growers use mixes made up of other materials, and coco coir is a perfect ingredient for this kind of seed starting mix.
Coconut coir is a great addition to a seed starting mix. It can also be used on its own to start your seeds in as long as you add fertilizer once seedlings start to grow.
The best type of coir for seed starting is one that’s finely ground and free of salt. You can actually use it on its own for your seeds or add in some perlite for extra aeration.
Keep in mind that coco coir doesn’t contain any nutrients of its own. You’ll either need to add a small amount of fertilizer to your mix or water your seedlings with a liquid fertilizer once they start sprouting.
You can also use coco coir as the base of a homemade potting mix. It holds water and nutrients well, plus provides air pockets in the soil for plant roots. All of this makes it a fantastic medium for indoor or outdoor potted plants.
Aim to make coconut coir around 40% of your potting soil. You can experiment with different amounts to see what works best for the plants you’re growing.
Add in garden soil and/or compost for nutrients and volume. Perlite or vermiculite is also a good addition. They’re both lightweight materials that help with drainage and trap air in the soil.
If you didn’t use any compost, it’s also a good idea to add some kind of slow-release fertilizer to your potting mix. This is especially true if you’re going to be using it for plants that will spend months in the same container.
It’s pretty easy to make a basic potting mix with coco coir, but feel free to experiment with all your ingredients to see what your plants like best!
Coco coir is such a good ingredient in a potting mix that it’s becoming more and more common to see it added to ready-made mixes. You can also use it to come up with your own perfect soil mix!
Not many people are lucky enough to have the perfect soil. Most of us have to deal with clay, sand, poor drainage, or some other problem.
Coconut coir is a great amendment or addition to all types of soil. It’s especially helpful for amending either clay or sandy soils, but it can help improve water retention, drainage, and aeration in any soil type.
For heavy clay soils, coco coir works to lighten and break up the soil while also adding more air to it. In sandy soils, it adds better water and nutrient retention capabilities.
No matter what type of soil you have, the amending process is the same.
Spread out a layer of rehydrated coco coir over the area you want to amend. Then, simply work it into the soil to a depth of at least 12 inches. Heavy clay soil can be difficult to break up, so you may need to keep amending until you get it where you want it.
Alternative to Peat Moss
One of the ways coconut coir is often marketed is as an eco-friendly alternative to peat moss.
Peat moss is a popular growing medium and soil amendment that gardeners have used and loved for a long time. However, there are a lot of questions about the sustainability of using peat because it’s considered a non-renewable resource.
Coconut fiber is a very renewable resource, since coconut trees grow new fruit every year. This is one of the reasons many gardeners are using it as a substitute for peat moss, which is not renewable.
Coir can be a good substitute for peat moss in many different applications. Both can be used in seed and potting mixes. Both help to amend soil by adding better water retention and aeration.
In some cases, coco coir is actually the better choice because of its fairly neutral pH. However, if you want to make your soil more acidic, there’s really no substitute for peat moss.
If you’re a gardener who has used peat moss a lot in the past, you might want to consider switching over to a coconut growing medium and saving peat for when it’s absolutely necessary.
Coco coir has become extremely popular with hydroponic growers. Hydroponics is a specific way of growing plants without using any soil.
Some growers have hydroponic systems that grow plants with their roots directly in water but most use some kind of soilless growing medium. The idea is to give plants nutrients through water rather than soil. This avoids pathogens and other problems that exist in traditional growing methods.
Hydroponics is a very unique system of growing plants, usually indoors, without any soil. Growers often use soilless mediums for their plants to sit in, and coconut coir has quickly become popular.
Sterilized and pre-rinsed coco coir is a perfect growing medium for hydroponics. It retains and releases water to plants, provides aeration, and can be reused if treated properly.
If you’re just getting into hydroponics or are interested in trying it, coconut coir is great because it acts a lot like the potting soil you’re used to from outdoor gardening.
For hydroponics, it’s typically used on its own or with the addition of perlite. All nutrients are given to plants via watering.
How to Rehydrate and Use Coco Coir
If you bought yourself a block of coco coir to try, you might be wondering what to do with it now. It’s not that hard to rehydrate but will take a little hard work.
The easiest way to rehydrate a block of coir is to do the whole thing at once. However, if you won’t be able to use it all, you can take small chunks off of the big block using a sharp tool or a small pick.
The first step is to find a container that will hold about seven times the size of the block you’re working with. If you’re doing this outdoors, a wheelbarrow is the most convenient mixing container.
For rehydrating large blocks of coco coir, a wheelbarrow is the best choice. It holds a lot of material and is at a good height for mixing.
Place your block into the container and add water. Depending on the size of the brick, it can take anywhere from a few to several gallons of water.
Let the water absorb and expand on its own for 15-20 minutes. Then, use your hands, a garden fork, or a shovel to break apart the chunks of coir and mix everything together until it’s uniformly hydrated.
Make sure there aren’t any dry spots of coco coir left after mixing, and add water a little at a time as needed. You’re now all ready to use it for growing!
Top Coco Coir Mixes
When it comes to actually shopping for a coco coir mix, there are a few things to look for.
The best mixes will be pre-rinsed to get rid of any salts that accumulated during processing. They should also be free of pathogens but preferably without the use of chemicals, meaning organic is best.
It’s also good to know the pH of the final product you’re buying to make sure it’s close to neutral. And if you’re just starting out, get a mix that’s already created for you.
Other than that, you can buy a block to get the most for your money, or go with a ready-to-use bag of loose coir.
Here are some of the top coco coir mixes to try:
- CANNA Coco Brick– This is one of the most economical options as well as being high quality. The compressed brick expands to 40L of material when water is added. The coir is organic and free of weed seeds, pathogens, and salt. The bricks have a hole in the middle to make them easier to rehydrate.
- Plantonix Coco Bliss Bricks– This is another block option that is OMRI listed, meaning it’s certified for organic growing. Blocks are pre-rinsed to remove salt and are about 1.4 pounds each, which makes them easier to work with. You can buy anywhere from 3 bricks to 90.
- Mother Earth Coco Bale & Mixes– Mother Earth coco is not certified organic, but it is pre-rinsed to remove salt and is a good blend of all the different fibers. You also have a few choices: the Mother Earth Coco Bale, their loose coco mix, and their Coco + Perlite ready-to go mix.
- Fox Farm Coco Loco Mix– This is one of the best options if you want a pre-made potting mix made of coco coir. It contains mostly pre-rinsed coir with perlite, fertilizers, and lime (for pH) added in. The great thing about this mix is that the added fertilizer means all you have to do is put it in your pots and add plants. Just keep in mind the mix is not sterilized and is meant for container plants, not seed starting.
Whichever mix you choose to go with, it’s not hard to discover why so many gardeners and hydroponic growers are raving about coco coir.
Try it out for yourself and see just how easy it is to work with!
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.