In recent years, coconut coir has been gaining popularity as a hydroponic growing medium. More recently, many gardeners are also using it in place of sphagnum peat moss.
So what was once a waste byproduct of coconuts that ended up in landfills has become a useful resource for gardening (and other things). Best of all it is environmentally sustainable.
So, if you’re wondering what coco coir is, how it is made, where it comes from and how to use it in your garden, this is a complete guide that will help you understand everything there is to know about coconut coir.
What is Coconut Coir?
Coconut coir is also known as coco coir for short. It is made from the husks of coconuts. This is the rough, fibrous, stringy section between the white meat and the hard outer shell of the fruit.
If you’ve ever been to Hawaii or other tropical destinations, you’d see people crack open coconuts, then scrape off the meat then just throw the shells including the husks to the side.
Fortunately, people found ways to use the coir. And, today, it is a common growing medium used both in soil gardening and hydroponic gardening.
That said, coco coir is also used for rugs, doormats, upholstery stuffing, ropes and other materials.
Interestingly, if you examine the coir, you’ll notice that there are two kinds of fiber present. One is brown, the other is white. Which one you end up seeing will depend on how ripe the coconuts are.
- Brown coir comes from ripe, mature coconuts. As such, they are stronger but also less flexible.
- White coir is present in coconuts that have yet to ripen. Thus, they have the opposite features being more flexible but not as strong.
How is Coco Coir Made?
Like other growing media, coconut coir in its original, raw state cannot be used for gardening. Instead, it has to go through a lot of processing before you get the finished product.
The entire process begins by removing the coir from the coconut. Because the husks are firmly stuck together, they need to be soaked in water to help soften then loosen them.
Depending on the manufacturer, the soaking process may be done in fresh or tidal waters. When tidal waters are used, the coconut coir will absorb a lot of salt that’s present in sea water. This can make it problematic for gardening purposes since most plants cannot tolerate high salt content (which is why there aren’t many plants near the beach or sea). Thus, and extra step of flushing the salt needs to be done later on.
The next step involves taking the coconut coir out of the water bath and drying them. This step takes about 12 months and is more complicated than just hanging them out in the sun to dry.
Finally, after the drying process is finished, the coconut coir are organized into bales then cut up and processed into the form that the manufacturer wants to sell them in.
Often, coconut coir comes in one of three forms:
- Coco peat (coco pith)
- Coco fibers
- Coco chips
These are what you get in the packages or boxes.
Along the way, steps are also taken to ensure that the products are safe to use with plants. This is often done via heat sterilization to make sure that there are no pathogens or potential diseases that can be passed to the plants.
This is a simplified explanation of the entire process which is long and extensive. The goal is to point out the basic process without making the explanation overly complicated.
As such, I have skipped extra steps including straining and grading of the coconut fibers.
Pros and Cons of Coconut Coir
Before you being using coconut coir, it is important to know the pros and cons of this substrate. This will ensure that you’re able to use it properly and avoid situations where it is not well-suited.
Pros of Coconut Coir
- Water retentive – makes it perfect for water-loving plants or those that enjoy moist conditions. It is also well suited for soils that dry very quickly or hot climates. This feature also makes it a good alternative to sphagnum peat moss.
- Low acid pH 5.8 to 6.8 – around this level, you get good nutrient availability to plants. In contrast, peat is more acidic at around pH of 3.5 to 4.5)
- Very good in soaking and absorbing water – absorbs 10 times its weight and water and allows plants to quickly recover from lack of water or dry conditions.
- Does not attract pests – is provides natural pest control since pests don’t like it.
- Can be repurposed – for environmentally conscious growers, this is the biggest benefit of coco coir over peat moss. This features makes coconut coir environmentally friendly unlike peat moss.
- Porous – allows for air circulation. Therefore, makes it easier to balance air and water to keep the roots of the plants healthy and growing.
- Slow decomposition – as a soil medium, this lets you use it for a long time without having to repot often.
- Sterile – the heat sterilization process ensures there are not weed seeds or potential diseases that can mess up your plants.
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Cons of Coconut Coir
- Needs to be rehydrated – sounds simple, right? Not really, unlike mushrooms you get from the store that you can just dump in water to rehydrate, coconut coir takes a bit more effort. They shipped compressed in boxes in the form of bricks. This helps cut shipping costs especially if you need a lot. But, the process of rehydrating it takes a bit more time. While not difficult, you’ll need to always go through the rehydration process before you can use it for gardening. The good news is it will expand to as much as 10 times what it was once hydrated.
- Pre-made mixes can be costly – because of the extra work, some manufacturers will sell pre-mad coconut coir mixes. This saves you the time and effort of rehydrating. The downside is, they can get costly.
- No nutrition – coco coir is inert. Thus it does not contain any nutrients to help with plant growth. This means you need to provide the nutrients yourself. It also means an extra step both for soil gardening and hydroponics. I’ll explain this more below.
- You need to mix it with other media – while its water retentive properties is useful, it can also become a problem if you don’t add a draining medium in your potting mix. Using too much coconut coir will cause the soil to hold too much water which will eventually become a problem for most plants. As such, it is not a good idea to have more than 1/3 of your mix made with coconut coir. This is also why perlite is often used alongside it in soil gardening.
Types of Coco Coir
One of the things you’ll notice in stores is that there are different types of coconut coir. In general, they come in one of three forms:
- Coco Peat (or Coco Pith)
- Coco Fiber
- Coconut Chips
But, the product you’re picking up from the shelves is actually a mix or blend of the three.
Of the three types of coconut coir, coco peat comes in the smallest size. They are the husks of the coconut that have been ground down to small bits. It a way they look lie dark brown wood shavings or peat moss even.
The benefit of using coco peat is that their size makes them absorb a lot of moisture and hold a significant amount of air. As such, you do want to be careful with overusing them because you can end up drowning the roots of your plants.
Additionally, it decomposes very slowly so you don’t need to keep replenishing it or repotting the plant to replace it with new substrate.
Coco fiber or coco coir fiber are more coarse compared to the peat. They are not chopped up or ground into small bits. As such, you have the long stringy fibers that look something like strands of hay that are tangled together. Some will argue that they look like mini tumbleweeds.
In any case, their long, fibrous properties allow lots of air pockets so the roots of the plant can breathe. However, it is not very good at absorbing moisture. So, it is useful for improving aeration rather than water retention.
Unlike coco peat, coco fiber also breaks down faster so you eventually lose the valuable air pockets.
Because of these features, coco fiber is often used as mulch or as a top layer.
Coco chips or coconut chips are the largest of the three coconut coir types. They look like small wood chips you’d use to flavor your barbeque. Although, obviously, they’re used for different purposes.
Instead of the fibrous form that coco fiber comes in, coco chips are small ununiform rectangular chips. They are not grounded nor are they chopped up.
This makes them work more like expanded clay pellets. But instead of being made of clay, they come from coconuts.
Coco chips are considered an in-between of coco peat and coco fiber. They’re able to provide air pockets. And, they can soak in moisture as well to keep your plants hydrated.
It is also worth noting that coco chips provide the highest air to water ratio of the three types.
Coco Coir vs. Peat Moss
Because of its ability to absorb and hold water while improving aeration, coco coir is often used as an alternative to peat moss. And, any time this happens, you know that people will start comparing the two items to see which is better.
Coco Coir is More Environmentally Friendly
Coco coir is a renewable resource. On the other hand peat moss is not. To clear things up, peat moss technically is sustainable since it keeps growing in the peat bogs. Unfortunately, growth is so slow (it takes hundred to thousands of years) that demand (people using peat moss) highly outstrips the growth.
As a result, lack of strict harvesting restrictions, the ecology of peat bogs will eventually get destroy and probably disappear over time.
Coir on the other hand comes from coconuts. And, as long as coconut trees are being planted and bearing coconuts, we’re not going to run out of coconut coir.
Additionally, using the coir of the coconuts helps reduce the amount of waste being thrown into the landfills, where the husks used to end up once upon a time before they discovery of its many uses.
Coconut Coir has a Neutral pH
Another thing worth considering when using coco coir or peat moss is their pH. Each growing medium has its own pH. And, pH is very important because it affects the availability of nutrients to plants.
In general, neutral pH allows more nutrients to be used up by the plant. However, you also want to check on whether the plants you are growing are acid or alkaline loving ones. This will ultimately affect how you’ll adjust soil pH.
Coco coir has a more neutral pH, whereas peat moss is acidic in nature with pH running around the 3.5 to 4.5 levels. As such, you may need to adjust the pH to make the environment hospitable to plants.
The value of both peat moss and coconut coir comes it their ability to absorb and retain moisture. This allows the roots to stay hydrated and prevent them from drying up too quickly.
When it comes to this feature, coconut coir wins out. That’s because it can absorb about 30% more moisture than peat. However, too much isn’t always a good thing as going overboard can cause your plant to get waterlogged, get root rot or eventually die.
This is something worth considering as well especially if you’re on a budget or don’t want to have to keep repotting or replenishing the growing media.
Coconut coir deteriorates slowly and in the process provides air pockets. Although it will eventually break down, this takes a long period of time.
So, you don’t need to keep repotting or changing the potting mix often.
This is probably the easiest to compare. That’s because coconut coir works very well for hydroponics. And, peat moss is not a good option for it.
Coconut coir is slightly cheaper than peat moss. But, keep in mind that there’s the extra work on your part as well where you need to rehydrate it before you can use it for gardening.
As a result, there’s the extra time and effort involved when using coconut coir.
Overall, everything is pretty close. The two biggest arguments are cost and their environmental effects. Of course, if you’re doing hydroponics, then coconut coir is the way to go.
But for soil gardening it really comes down to the two factors. Then, there’s the addition of extra work of having to rehydrate coco coir before you can use it.
As such, if the small difference in cost is ruled out and you don’t mind the extra time and effort for rehydrating, it will really come down to how you feel about their environmental effects.
Outside of that, it is really based on your preference and which you feel you’re getting better results with.
How to Add Nutrients to Coco Coir
When using coco coir, it is remember that you’re not getting a nutrients with it. Because it is an inert growing medium, you’ll need to supplement the plant nutrients yourself.
The two nutrients you want to keep in mind are Calcium and Magnesium, both of which are essential nutrients needed by plants. As such supplementing them is needed.
Another thing to consider is that depending on how the coconut coir is processed, you may end up with other nutrients. These include potassium, manganese, copper, iron and zinc.
How to Use Coconut Coir
How you use coconut coir will depend on what you want to use for.
- For soilless potting mixes, it needs to be mixed with perlite or vermiculite for drainage. Adding compost for its organic matter content is likewise helpful.
- As a soil amendment, you can use it for clay soils to improve drainage. For sandy soils, it will help improve water retention.
- For hydroponics, it works well as a hydroponic growing medium. It has a neutral pH and a high CEC level so there not need to modify pH and the nutrients are kept in the root zone.
- For starting seeds and rooting cuttings, coco coir can be used as growing medium. It holds enough moisture to keep them from drying out. Coco coir also has anti-fungal properties.
When using coconut coir, there are a few thing to keep in mind.
- Coco coir comes in compressed brick form. This is what you’ll get when you open the package. And, it will take at least 20 minutes or so of soaking in water to rehydrate the coconut coir before using it.
- As a hydroponic medium, you’ll need to use enough nutrients to make sure that there’s enough calcium and magnesium for plant growth.
- Be careful not to overuse coco coir in your mix as a high concentration will increase the risk of retaining too much water which can drown the plant.
- Perlite is a common medium that’s used alongside coconut coir to improve drainage.
- You can also add pebbles to the bottom of the pot to allow excess moisture to drain better.
How Not to Use Coco Coir
Because of the versatility of coconut coir, there aren’t many instances where you can’t use it. The key is making sure to soak it first then knowing how to use it depending on the application.
Here are some things to remember when using coco coir.
- Don’t forget to soak the bricks before dividing them. Or your could scrape off bit by bit as needed and soak that amount. Be careful when you do because the brick is compressed and stuck quite well together.
- Unused coco coir can be stored in containers for many years. So, don’t throw them away.
- Avoid using it on its own in container plants. It needs to be combined with a well-draining medium like perlite, sand or vermiculite.
Beyond that, there isn’t a lot of issues with coco coir.
You can use it for starting seeds, hydroponics, rooting cuttings, growing plants in containers and garden soil.
How to Choose Coco Coir
Like all products, not all coconut coir you see in the store are the same. In addition to mix of the types of coco coir, you want to consider how the material was harvested, processed, prepared, and packaged.
The entire process takes a few years to complete from the time it is harvested until it is sent out to the garden centers. Thus, the care, processing and handling all affect end quality. Also, some companies will take shortcuts or not follow best practices.
You also want to make sure that the product is sterilized so it is pathogen-free. In this process, some may use steam, heat or chemicals. Each of which will have varying effects on the longevity and safety of your coco coir.
This means checking with the garden center regarding the company or brand before purchasing. Of course, doing your own research goes a long way as well.
- How the facility of the manufacturer keeps everything clean and free of pathogens
- Are they following best practices in aging the coir
- Do they wash and filter out all the salts
- What kind of bend of peat, fibers and chips is included
- How the packaging works