What is Coco Coir?
I think the first thing to talk about when discussing coco coir is: what exactly is coco coir? Firstly, these terms are interchangeable. Some shops and growers use coco and some use coir as their term of choice. We prefer coco and this is the most used term in the specialist hobby market.
Coco is made from the processed husks of coconuts. Very simply, coconut husks are soaked in water to soften the fibres and then they are shredded to create either fibres, chips or pith. When you are buying a bag of coco, you are usually buying a blend of fibre and (mostly) pith. It is the ratio of pith to fibre that affects the overall drainage and water holding capacity of your coco coir growing medium. Coco mediums are optimised for the air to water holding ratio. You will mostly find coco chips in orchid mixes. You could sum it up like this:
- Pith for water retention
- Fibre for aeration
- Chips for orchids (not the focus of this article)
Coco: Bag or brick?
Coco is sold in 2 formats. Either in a 50L bag or as a compressed (dehydrated) brick or block. Each has its own advantages and disadvantages. Buying a bag of coco requires less preparation work as you can add it to a pot and off you go. Buying a compressed brick requires that you soak it in warm water and rehydrate it before you can add it to your pot. Bricks require more work to begin with, but they are easier to carry as well as being cheaper than bags of coco. Most growers opt for bags of coco to save on the initial hydration work. We have a handy guide on how to re-wet coco bricks and if you follow these instructions you will be successful.
Something else to understand about coco is that it naturally contains sodium and potassium. In the manufacturing process, this is usually reduced by washing the coco thoroughly and adding calcium. This is known as buffered coco. Most coco you will find in a shop is already buffered so you don’t have to do that.
So far, I have told you lots of technical stuff about coco. If you were to stop me in the street and ask me to describe coco, I would tell you that it looks like soil, feels like soil but it’s airier and it will give you a better overall result than soil. The last point is, of course, open to debate!
One point to note, like in any manufacturing processing, there are degrees of quality and buying a RHP or similarly accredited coco medium is the safest option. Most grow shops only sell RHP accredited coco but do check before buying.
Growing in Coco Coir is Suitable from Novice through to Professional Growers
Now we know what coco coir is, let’s just start by saying that coco is a growing medium I would recommend to anyone from novice right the way through to professional grower. Think of it in terms of skill levels. A novice grower can and should succeed when growing in coco, but they won’t get the same result as an experienced professional grower. Likewise, in terms of performance, the professional grower will not be limited by growing in coco. They can achieve the absolute peak of performance when growing in coco. This is one of the reasons why growing in coco is so enjoyable and rewarding; the only limitation of what is possible is you – the grower.
The 3 Disadvantages When Growing in Coco
There are disadvantages to growing in coco, but what is a disadvantage without a comparison? I am not going to run this article as a comparison though, but I will highlight alternate options that, of course, have their own disadvantages (and benefits).
Disadvantage 1: Technical – Nutrient Management
Imagine this: you put a seed in a plant pot, you go to the tap and fill up your watering can and you water your plant. You keep on doing this for another 8 – 12 weeks and then it’s time to harvest your crop. Well, growing in coco is almost nothing like that! But you knew that already!
Now the reality: You put your seed in a small pot of coco growing medium. Coco contains almost no fertiliser so you must always add a nutrient solution when watering your plant. As you are just at the seed stage, you will want to give your plants the best start you can. For this you will Shogun Katana Roots stimulator and Shogun Start both of which are essential to get your seedling off to the best possible start. Not only that, but you must continue using Shogun Samurai Coco nutrient formula which is specifically formulated for the coco growing media right up until harvest. And this sums up the first disadvantage: coco coir contains almost no nutrients, and it requires nutrient management from seed through to harvest.
Before I make nutrient management sound like a chore, it is precisely the fact that you can 100% control the nutrients that you feed your plants that makes this growing method effective. Not only that, but coco in the UK is by far the most popular growing medium used by around 70 - 80% of growers. In mainland Europe, soil is the most dominant growing medium followed by coco coir. (Source: In-house research, Oct. 2026)
So, what exactly are these nutrient management disadvantages?
pH & EC Control. Very simply, you need to feed your plants the correct strength nutrient within the correct pH range of 5.8 – 6.3 but you can get away with 5.5 – 6.5. But don’t worry if you make mistakes here, as one of the coco’s disadvantages is also an advantage in that because it contains almost no nutrients to begin with, you can always flush through with water and get it right next time around.
Calcium and magnesium deficiencies! This is something growers love to talk about – and coco coir often gets the blame! It is true that growing in coco can lead to these deficiencies but if you are using a decent quality buffered coco coir in the first place along with coco specific plant nutrients then you should be OK. Nevertheless, calcium and magnesium deficiencies aren’t uncommon especially for those growers in soft water areas (tap EC ≤0.4) and adding Shogun CalMag solves the problem.
Disadvantage 2: Physical - It’s bulky.
I have been in this industry since the early 1990s, and in the early days coco coir wasn’t readily available for hobby growers. That didn’t happen until early 2000s and then only in a very small way to begin with. Before then, almost all growers were using hydroponics. It didn’t matter whether you were expert or a novice everyone learnt and nearly everyone succeeded at hydroponics. One of the benefits for everyone concerned was that apart from clay pebbles in flood and drain systems there wasn’t much heavy lifting of growing media to do. The dominant growing system of the day was the Nutriculture NFT Gro-Tank which used no growing medium, only water and nutrients.
Fast-forward to the late-2000’s and growing in coco started to really take off.
It’s bulky. Coco coir growing media is usually sold in 50 litre bags and depending on your pot size and the size of your grow you could be buying and transporting quite a lot of 17kg bags of 50L coco. If you are growing 20 plants in 16L pots, that is 7 bags of coco. It’s do-able but not always ideal.
Disadvantage 3: Environmental – disposal
Disposal. How do I get rid of my old coco? Finding a way to dispose of used coir is a problem for many growers and a boon for many others. The easiest and best way is to take your used coco coir outside and dig it into your outdoor garden. Your veggies will thank you for this now nutrient rich aerating medium being dug into the soil. If you live in an apartment without access to an outdoor garden, then this is more of a problem. My suggestion would be to talk to allotment growers and see if you can give them your waste (used) coco coir. Any allotment grower worth their salt would readily accept this offer.
The environment. What about recycling my coco coir instead of disposing of it? Before we dig into recycling, let’s not ignore the environmental aspect of shipping container loads of coco coir from places like Sri Lanka and India over to Europe. There is a real environmental cost to that, but to some extent this is offset by the fact the peat is no longer used in growing to all our benefit.
Recycling your coco coir growing media is an option to reduce but not eliminate waste and save on costs. For many years growers would just use their coco once and then dispose of it in any number of ways. However, it doesn’t have to be this way. Nowadays a lot of growers use Shogun Zenzym to keep their coco growing media fresh and healthy throughout the grow. Then at the end of the growing cycle, they remove the old roots and create a new coco mix of 50% old coco growing media and 50% brand new growing media. It’s a way of saving money and many growers swear by the results.
Remember coco is a 100% naturally derived product so ultimately however you end up disposing if it, it will biodegrade.
The 3 Disadvantages of growing in Coco Coir and potential remedies
| Technical – nutrient management |
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| Physical - bulky |
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| Environmental - disposal |
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As you can see, growing in coco coir does have its disadvantages but the fact that it is so popular tells you a lot. From my perspective, I think it’s a great medium. I like the look and feel of it, and I like the fact that I am in complete control of what I feed my plants and above all it feels like a very natural way to grow a plant. It feels like a decent blend of science and nature.
About the author
Justin Henry
I’ve been in the industry since 1994, starting out as a retailer which I did for 25 years. I co-founded Aqualabs with Dr Callie Seaman and Simon Spinks in 2013 and we manufacture the Shogun Fertilisers range. I remain passionate about plants and the industry.
