• If you need help identifying a pepper, disease, or plant issue, please post in Identification.

media A guide to growing peppers in coco coir

Hello everyone!
I've always been fond of experimenting with all kind of different stuff, this led me to give growing in coco coir a go.
I'll bundle all the methods I use and that work for me so far in this topic, and I hope I can help some curious people with it.

The coco itself:
I myself grow in coco coir produced by Plagron. You should try to find high quality coco coir soil that has been washed in the factory, since unrefined coco coir may hold a lot of salt, and as well all know, salt is not exactly a friend of peppers. You could use compressed blocks of coco coir and expand them in a large container as shown below:
These types of blocks of coconut coir may still hold quite a bit of salt in them, so I would advice that after expanding them and putting them inside your pots, you rinse it very thoroughly with reverse osmosis or distilled water until you have a nicely clear runoff coming out of the bottom of your pots. This will get most of the salt out.

When growing peppers, which are quite prone to overwatering, I would mix at least one third in volume of perlite in your coco mix, or you can buy coco coir with perlite already added!
The addition of perlite gives a lot fluffier growing medium that can hold a lot of oxygen despite being constantly wet. Making it very hard to overwater your plants.
I've also heard and sort of experienced that you do not need extremely large containers when growing in coconut coir, your seedlings will become relatively large in relatively small pots. I'll have more knowledge about this in a later update since i'm still in the middle of my first grow. I
I would also recommend you to add a small layer of expanded clay balls or hydroton on the bottom of your growing containers to encourage better draining and holding some air in the bottom of your pots, just as an insurance policy against overwatering.

The nutrient solution:
You can find a couple of different coconut coir specific nutrients, which would be a good starting point. I myself run with General Hydroponics FloraNova series, since it's quite easy in use and very concentrated.
You will need some sort of a pH testing kit for growing in coconut coir. You can get these relatively cheap online, maybe even in your hydro store. Optionally you can get an EC or PPM meter too, to measure how concentrated your nutrient solution is, but if you use your nutrients sparingly (below full strength as described on the bottle, I'm sure you'll do just fine without one).
Firstly though, you'll need either reverse osmosis water or plain tap water to start making your nutrient solution. Use a PH-down product designed for hydroponics to lower your pH to between 5.5 and 6.5, more specifically I use 5.8 to 6. After lowering the PH of your nutrient solution, you can add your hydroponic nutrients in a conservative manner, i.e. : always use slightly less than directed on the bottle.
Even though I go by the nickname Fertilizer on this forum, I've had nutrient burn occur in some of my plants, which makes me a bit nervous to use full strength solutions, I advice you employ the same caution.
Mix everything up well and let the nutrient solution come up to at least room temperature, you dont want to shock your plant's roots by adding very cold or very warm nutrients.
Now, if you use reverse osmosis water, you should add a small dash of CalMag to your water, as coconut coir tends to hold very firmly to calcium and that may or may not result in a calcium deficiency in your plants, I wouldnt take any chances if I were you. Now if you have very hard water, like I do, you most likely will not have to add any calcium supplement to your nutrients, since hard water is full of calcium already. You could use half a teaspoon or less of Epsom Salts every other time you make a nutrient solution, this is the current strategy i'm using. 

Some resources on your nutrient solution:
Now, I've been watering either every day or every other day (just regular top watering with the nutrient solution, like you would do with soil plants), this seems to work fine for me (keep in mind, I'm not yet an expert on this and will need some further experimentation too).
I've heard a lot of discussions about this, mainly on cannabis growing forums. Some people advocate you water small amounts of nutrients multiple times per day, once your rootzone is fully developed.
That being said, I'm sure you can get away with watering just once a day or even way less, since coco coir will stay wet for AGES. 
I also advice that every time you water, you water till you have a runoff of about 20% of the volume you watered, coming out the bottom of the pot. The idea behind this, is that you are flushing nutrients salts that may have build up during your regular feeding, out of your growing medium. If you have the spare cash, I'd recommend getting some FloraKleen by GH and using their protocol once a month or once every 2 months, just to be on the safe side. But this is not imperative by my understanding. 
I have no experience with dripfed watering or ebb and flow systems, so if you have good knowledge about this, leave me a PM and i'll add your info to this guide.

Some more resources for those interested:

That's more or less it for now, if you have any suggestions, or you spotted any mistakes on my part, feel free to leave me a comment or a PM!
If you guys want any more info, also just leave a comment and i'll try to answer your questions to the best of my abilities!
Thanks for reading guys.

This is a good start for a primer on coco. I am just going into my 3rd grow with coir and have had decent results so far. I have a few points of difference from what you've posted above. I want to be clear that I'm not here to say what you've posted is wrong, just that my limited experience with coco has been different. I offer up my experience as information only.

The coco itself:

I agree with most of what you posted here. I'd add that not all coco is the same. Some contains more salt than others. Some have a course grind, while others have a lot of very fine pith. Some have hair like strands, and some have large chips. Whatever the composition, it's always best to buy a high quality coir from reputable sources like hydro stores. While I have read that compressed bricks can contain higher salt levels than loose bags, I haven't really noticed much difference given that I'm still buying the bricks from a hydro store and of a reputable brand, namely General Hydro CocoTec (http://generalhydroponics.com/cocotek-1/su4dobc0t7ont4cimy57rk6fad08vo).

I expand the coco bricks with a mild mixture of CalMag and warm water - 5ml/2L. Some recommend 1/4 strength nutrient mixture of whatever you're using. Either way you want to have the coir "pre-charged" as they say. Using plain water or RO water does not do this. I too water heavily for the first few times to ensure the coco is 'clean' after I expand it. Call it a paranoid habit.

I have used loose coco in bags such as Royal Gold Coco Fiber (http://royalgoldcoco.com/coco-fiber) and had decent results. I've also used Canna Coco in the loose bags and had decent results. That said I found both manufacturers have added far too much fine pith to the mixture for my liking - and it seemed to be a bit much for the plants too. Drainage was poor and the pots remained wet for a long time. I suspect this is why some people recommend adding perlite to the mix. I have tried adding perlite to coco and had ok results. Not great, just ok.

From my reading of the 420 sites, some argue that coco already has the perfect balance of air to water ratio and that adding perlite does little more than disrupt the balance. Others argue that perlite is necessary because the coco holds too much water. I think there's a bit of truth in both assertions, but that it depends on the coir composition. As I mentioned above, some manufacturers seem to add a lot of very fine, espresso like grind pith to the mixture. Others have a mixture that tends to be on the course side. My preference is to the middle. 

Although I had decent results with both Royal Gold and Canna Coco, I found that they contained too much fine grind pith and that perlite didn't really address the issue. I had a partial bag of both and didn't want to waste the money spent on the coco so I looked for a solution. For me, it came down to me needing to run the coco through a steel mesh strainer to remove the really fine pith, and keep the medium grind coir.

The strainer I use to sift the coco. I would put a few handfuls of coco into the strainer and banged it against the palm of my other hand until I felt that I had removed enough of the fine pith.

Strained coco - fine pith on the top, course coco on the bottom.

I've found that after I've strained the coco I get EXTREMELY fast drainage and it produces an excellent root zone medium for chili plants. It also allows me to use pure coco rather than perlite mixes or putting anything in the base of the pot to aid in drainage. Like last year, I will spread the fine pith over my lawn this spring.

When it comes to watering, it is very hard to overwater in coco. I say this because you could pour a gallon of nutrient solution into a shot glass sized pot with a seedling of a plant. Coco will only hold so much water, all the rest drains off - which is a waste when it comes to nutrients. You want some run off, but not as much as in this example. That said, unless you have the right conditions (heat, established root ball, propoer pot size, proper grind coco, and enough light) you CAN water too often. For example, cool conditions, a pot too big, fine grind coco, and an unestablished root ball tends to result in algea/slime on the top of the coco. I often see this in my early starts because winter temperatures can drop to -20c in my area and I keep the house at a cool 18.5c at night. I think I've solved the problem by using a heat mat under the tray. It helps keep the media warm and allows me to water every few days.

As summer approaches, things warm up a bit and the plant establishes itself, I find that you can water multiple times per-day. This is where you really see the plant grow. Until the plant establishes a root ball, I water when the pot is half the weight of a freshly watered pot. You get a feel for this after awhile and know when you need to water.

Well established root ball that can take multiple waterings a day. 

I would like to talk a bit about watering frequency, nutrients, and pot size, but that'll have to wait until another day.

The Nutrient Solution

Nutrients, and the role nutrients play in coco coir are two extremely important points that you need to understand IF you used to grow in soil and now want to switch to coco. I simply cannot stress it enough. Soil and coco are NOT the same and they cannot be treated the same! They both have their own unique needs you have to consider if you want to achieve the best results.     

There are literally 1000's of hydroponic products out on the market today. I found it extremely confusing when I first looked into alternatives to soil. Outside of general advise on hydroponics I didn't receive a heck of a lot of help from the hydro stores in my area. I would scan the walls and shelves that were full of nutrients and would read the labels. All-in-one nutrient solutions, multi-part nutrient solutions, base nutrients, grow and bloom, coco specific nutrients, Organic, semi-organic nutrients, PK boosters, flush or cleaning products, root stimulators, benefitial microbes, zym's, ryzotonics, silica, wetting agents, PH adjusters, the need to measure Total Dissolved Solids (TDS) - be it Electroconductivity (EC) or via one of the various measures of Parts Per Million (PPM). It can be extremly frustrating and overwhelming to someone just getting started. The nutrient manufacturers aren't much help either. According to them you NEED EVERY product they sell in order to have a successful grow. Not only that, if you use all their products you'll be better looking and the girlfriend you had in grade 11 would never have cheated on you.

I turned to the internet for info and quickly found that there is very little information on chili plants and coco. Every search I did churned up a gluttony of what I'm sure were purely medicinal sites full of people legitimately growing herbs to aid in their glaucoma treatment and nothing more.

What type of nutrients should you use? That depends on how involved you want to be and how much you're willing to spend. Given that there are SO many nutrients out there, this is a VERY brief overview with little to no technical information.

1-part, or all-in-one nutrients 

As the name says these nutrients are just that. They claim to contain everything you need to feed your plants in one simple bottle. From what I understand 1-part solutions are rather difficult to manufacture because of the reactions that occur when certain elements are mixed together in high concentrations and in the same bottle. There are others, but calcium and Sulpher are a couple of well known offenders in this example. Given the right conditions, they can bond with other elements and produce precipitate, or fall-out. The problem here is that your plant needs these two elements and precipitate generally removes them from the equation. 

1-part nutrients simply require that you add them to water and then adjust the ph level.

Botannicare's CNS17 is a good example of a 1-part nutrient solution
A fairly obvious and easy way to avoid fall-out is to keep the offending elements separate by putting them into different bottles. Then users can combine the two solutions in water when they are needed.

2-part, or multi-part nutrients

As the description implies, these are multi-part nutrient solutions and come in more than one bottle. Each bottle has a number of elements, but because they are separated into more than one bottle, neither is complete until you mix the two together in water. Multi-part solutions like these are always sold togther. For example you'll often see a products labelled as "A" and a separate bottle labelled as "B". In this case you need both bottles and you need to mix them in water in equal amounts if you want a complete nutrient solution.

Canna Coco A & B is a good example of a 2-part nutrient
General Hydroponics Flora Series is another good example of a multi-part system - it's also the one I use most frequently because it's cheap, effective and available almost everywhere.


Oh this is a huge can of worms that I really don't want to open. There are WAY too many additives and aside from researching each one individually it's hard to say which are snake oil and which actually work. I suspect that this is where nutrient manufacturers make the bulk of their money. New and improved additives are always popping up. They almost always have some claim to increasing yield, oils and flavor.

I really only have experience in using Canna PK13/14 and Botannicare CalMag+.

Canna PK13/14 is typically used during the bloom phase of a plants life. It increases the overall level of Phosphorus (P) and Potassium (K) in your solution. PK13/14 aids in flower growth and overall fruit production. I had a huge explosion of flowers in the few times that I've used it. I also ended up with a lot of flower drop for some reason. Something was out of balance, but I'm not sure what.


I've read that you need to add extra calcium and magnesium when using coco. It's often a blanket statement that's neither right or wrong; rather it depends on the situation. I like to use it when I'm expanding my coco bricks to help buffer or pre-charge the coir. For the most part, coco specific nutrients have enough calcium and magnesium in them to overcome the fact that coco locks up calcium. There are exceptions and I'll cover it below.

Calcium and Magnesium are often sold together in the same bottle. This is because they aid each other when it comes to the plant being able to use it. The nice thing about the calmag products is that the manufacturer's have mixed the appropriate ratio's of calcium to magnesium. I can't recall what the exact ratio is, but have seen reference to a 3:1 or 4:1 ratio.


Obviously this is a vital component to hydroponics. Generally speaking, the cleaner the water, the better. But not always. Reverse Osmosis (RO) water is often recommended for use in hydroponics simply due to the fact that there's very little total dissolved solids in it (typically less than 10ppm). It's clean. When your water is this pure, you are able to control the type and level of all the elements that go into your nutrient solution. You want, and your plants need, a number of elements in the correct ratio's if they are to grow optimally.

When I first started dabbling in coco, I had tried plain tap water for my nutrient solution. Things went sideways fast! I tried a different nutrient line because I didn't know any better. I then tried another nutrient line. It wasn't until I purchased the HM COM-100 TDS meter where things became clear. My water tests at 500ppm. I don't fully know what's in it, but my water is very hard. This was throwing my nutrient mix out of balance. Too much of one element can lock out others. Your plant will suffer.

HM COM-100 TDS meter

My faucets look like this. We go through a tremendous amount of CLR here. The water has killed two coffee pots in less than a year. Our shower heads and faucets are always spraying in all sorts of crazy directions. Our kettles need to be soaked for hours on end just to get rid of the build up.

It's disgusting. My plants would turn yellow, crumple up and drop leaves. Once I figured out what the problem was, I switched to Reverse Osmosis (RO) water and things turned around immediately. As I mentioned the purity of RO water is fantastic and theoretically it would be the best choice for mixing your nutrients. That said, some manufacturer's actually design their nutrient line around the presence of hard water and recommend avoiding RO water. Canna Coco A & B is one of these lines. They design their nutrients around the idea that your water will have approximately 200 ppm of Total Dissolved Solids and adjust the balance accordingly. If you choose to use RO water with their lineup, they recommend you add a bit of CalMag to the water first otherwise you may see deficiencies in your plants.

I think I had better stop here for the day because I believe I'm begining to ramble at this point. I would still like to provide a bit more input on other areas of nutrients such as the need for coco specific nutrients, or standard hydroponic nutrients.



Inactive Members
Great information all around.

Glow provides a good general resource through manixbotanix.com. Yes, he sells nutrients, but there is more factual information (citations and references galore) on coir there than most cannabis forums.

I would say I find it preferable to add nutrients and then pH. The only time I pH before nutrient is with high alkalinity and a knowledge of how much of a drop in pH nutrients give.

But then I'm 20ppm out of the tap ;)

Excellent results Blister. I've thought of building a cylindrical tumbler to grade bricks. I use Canna religiously but have noted similar criticisms. The price is ridonkulous and most resources reference 4+mm particle size as ideal.

Stoked to finish this H&G base and switch to Jacks/Calcium nitrate. A farkin 25lb bag costs as much as the 4L base combo of H&G. Even with exorbant shipping costs it's a fraction of the price.
Thanks for the link Mig! I completely agree on getting info from the forums. You have to sift through a lot of manure before you find the seedlings of info. There's a lot of info out there and not all is equal. It's a lot like reading reviews of anything you're looking to buy. Some people bought an item, used it for 3 minutes then posted that is DA BESS EVAR!

I want facts. I want science behind the item. I want pictures and documentation.

Oh and the link is http://www.manicbotanix.com. you accidently put an 'x' inserted of a 'c'.

I prefer to use coir bricks (i'm unsure of the brand name). I sieve the re-hydrated media through window-screen-sized mesh (sorry, i don'tknow the term the local hardware store owner uses for this gauge of mesh, but it's window-screen mesh...).

The amount of water used in such a process ensures that the salt and excess humic/fulvic acids are leached out.

The coarse material is used for peppers, epiphytes(ie.: orchids, staghorn ferns, bromeliads, etc....), or any other plant which neesds good drainage. For plants that also require high-pH/high-calcum media (hoya vines, Stapelia species, American Southwestern cacti, lilac bushes and kale seedlings [they are, for a brief approach window, vulnerable to one of the 'damping-off' fungal diseases -- i suspect that it is Botrytis cinerea] and the high drainage profile of this media really helps for one of the most productive foliage vegetables in our climate), i add some crushed clamshells.
The fines of this media are equally useful: i use them as a media for rooting cuttings and for any plant that enjoys a wet or acidic root environment -- insectivorous plants (ie.: Venus' flytrap, Rhododendrons, etc.). The excess goes into window-boxes, planters, or gets donated to a friend's hobby (below)

There is a net gain from this approach, in quantity as well as quality, because a brick that reconstitutes to a volume of mixed particle sizes amounting to, say, 8 or 9 litres, will yield about 6 litres of coarser (better-drained, more pepper-friendly media) and about 4 liters of coir fines, suitable for acid/moisture-loving plants.
That's about a 20% gain, in total volume of mixed-purpose planting media. It's a messy bother to screen wet coir, but heyyyy-y-y-y... this whole thing is a hobby for me, right?
I usually offload some of my coir fines on a friend who propagates African violets (genus Saintpaulia), and enjoy the anti-fungal 'crop insurance' value of the drainage profile i get from the soil-less media i obtain from the process.
miguelovic said:
Great information all around.
Glow provides a good general resource through manixbotanix.com. Yes, he sells nutrients, but there is more factual information (citations and references galore) on coir there than most cannabis forums.
I would say I find it preferable to add nutrients and then pH. The only time I pH before nutrient is with high alkalinity and a knowledge of how much of a drop in pH nutrients give.
But then I'm 20ppm out of the tap ;)
Excellent results Blister. I've thought of building a cylindrical tumbler to grade bricks. I use Canna religiously but have noted similar criticisms. The price is ridonkulous and most resources reference 4+mm particle size as ideal.
Stoked to finish this H&G base and switch to Jacks/Calcium nitrate. A farkin 25lb bag costs as much as the 4L base combo of H&G. Even with exorbant shipping costs it's a fraction of the price.
What he said. In order to effectively leach the excess humic/fulvicacids, add some dolomite, cal/mag supplement, or other alkaline agent -- if you have tapwater as soft and uncontaminated as ours -- should be added... Miguelovic, you are right. We are blessed to have water of this low-solute quality, and to have water that is treated with elemental (diatomic) chlorine, rather than chlor-amine.
I am growing chilis in coco coir and using airpots as a containers. I think these air pruning containers are the perfect combo for coco growing, as they drain fast and let the roots get a lot of air circulation. Fertilizer used for every watering is mixture of Ghe mato+micro. The coco coir i use is the Ugro coco and it works great.
You sure it's not just SO hard that your pen exploded? lol.
Well, there must be worse places than my sub 300ppm :) I hear in LA, CA they get up to 600-700ppm sometimes.
I'd just like to post a few pictures of the growth I'm getting from my plants in coco. I'm using GREATFULLH3AD's formula:

- 4L RO water
- 6ml Flora Micro
- 9ml Flora Bloom
- 5.7 ph
- ~700ppm

Here are my plants from Feb. 11, 2016. They were just potted up.

Here we are March 3, 2016 - 22 days later.

As to the question of being able to grow larger plants in smaller pots, I can say that yes you can. This is a plant that I had grown when I first started dabbling in coco. It turned out that it wasn't what I had thought it was and had to scrap it. The plant is in a 4" diameter pot.

Perhaps the most impressive thing I've seen with coco is below. The plant is from my first adventures into coco. The roots had grown so much that they were actually poking out the top of the coir! All of the white strands you see are roots. I've NEVER seen this with soil. I've also never seen the growth I'm getting with soil either.