First time coir user, anything to watch out for?

[Quixote]

I just picked up a package of coir (coconut fibre soil) and want to start using it in my cactus soil mixes - for both a couple of potted indoor Trichocereus and maybe also a Lophophora later.

I'm wondering how much of it to use, and how it compares to spaghnum.

Any typical newbie coir mistakes you can warn me against? (pH, moisture retention, compacting issues, nutrients, heat, soil breakdown over time, whatever you can think of...)

Edited January 16, 2014 by Quixote

[djmattz0r]

I am somewhat of a coir newbie as well but have not had any problems using it so far. I have made a few different mixes with it ranging from about 10% coir to about 50% and everything is still alive. I use it for filler and water retention mainly. Hopefully someone else will chime in too.

Edited January 16, 2014 by djmattz0r

[hostilis]

I use it for my pereskiopsis soil. I mix 3 parts fox farm soil, 2 parts coir, 1 part worm castings. It works great. I have used it before in cacti mixes, but I preffer not to anymore.

[Quixote]

I use it for my pereskiopsis soil. [...] I have used it before in cacti mixes, but I preffer not to anymore.

What made you stop using it then ?

[franky]

It greatly aids water retention, as an ammendmant no more than 30% imo is needed depending on genus you are growing and even species. For those bottom watering coco greatly aids the capillary action of a medium!

[prier]

I haven't used coir in cacti mixes, really don't see the point. What has got me worried here is that you mention your Tricho's are inside. If you're going to grow cacti inside (this does not come recommended), make sure they are in an exceptionally well draining mix. You only need to water half as much as your outdoor plants. I think coir would be a bad idea in this situation.

[DiscoStu]

I just picked up a package of coir (coconut fibre soil) and want to start using it in my cactus soil mixes

why? what are your mixes consisting of where you need the water retaining properties of coir?

Lophophora

i wouldn't. if you keep you coir dry enough that a loph would like it becomes hydrophobic but if you keep it moist it's far too much water for a loph. keep in mind that lophs grow in the desert, not subtropical rainforests.

also what prier said.

[hostilis]

What made you stop using it then ?

I came up with a more simple mix for them. So I just use that now. It's basically just pumice and potting soil that I use now.

[franky]

I have only found peat moss to be hydrophobic, coco peat absorbs water very well wet or dry and does not shrink

[GoOnThen]

I have been trialling coir for a couple of years as an additive to mixes and straight with perlite. There are a couple of things that you need to be aware of when starting to use it. First is a lot of coir when processed they use salt water and if they don't wash it well with clean water it will still have some salt in it. This is more so with coir packaged for commercial growers but it is a good practice to flush it well with water before using it. If you are buying it as a brick the you need to hydrate it any way so I just put it in large plastic pot and flush water through it a few times once it is hydrated.

Coir also comes in many different forms ( sizes) the very fine cut which is sold for seed raising will hold a lot of water and stay wet for a long time so small amounts added to a mix can change its water holding capabilities a reasonable amount. I still use some in my seed raising mix along with some store bought seed raising mix but the total of the two would only be around 20 % of my total mix the rest is mineral. The next size would be the more fibery ( longer strands ) and then the bigger chunks like what that sell as mulch here.

The coir that I have is in pre packaged long slabs that are made for the commercial hydroponics industry ( my brother grows hydroponic capsicums commercially )

Out of these bags I can if I want to separate the three different sizes but the main things that i use it for is an additive to potting mixes. I did initially sieve out all of the chunks but these days if the mix is for large pots I just add it as is but for smaller pots I will still sieve out the bigger pieces.

I will use around 35% in my mixes for Trichs along with around 35% store bought cacti mix and perlite. I don't measure any more I just eyeball it. If it looks and feels good the it goes in the pot. What I have found is I have reduced the amount of perlite in the mix as the coir makes the mix more open and so it does dry out fast.

I have used the same mix for my Pere but I have mostly change back to straight cacti mix as the coir dried out to fast for my liking.

All of the larger pieces that I sieve out I put to one side and use them in mixes for bromeliads.

These have been in a mix of potting mix, coir, course sand and perlite for a few years now.

This one has been in the same mix for a couple of years ( mainly coir and perlite ) . It is a lot bigger now and seems happy. I do need to water it regularly as it does dry out very fast.

The best thing to do is run some trials for yourself as everyone's conditions are different just don't use your favourite cacti as the test subject.

Cheers

Got

[gtarman]

If you're sourcing it from down under I'd say be very careful. Dropbears have been known to lay their eggs in coir

[franky]

I have found the bunnings premium coir garden soil to be of adequete pore size on par with hydroponic counterparts.

on the flushing, potassium chloride is largely found in unflushed coco and can actually be of use in propagation of some plants eg tomatoes etc I am not experienced with cacti growth so I cannot comment on that as I'm a newbie to cacti still.

one more thing if coco constitutes a majority of your mix and you are not using pre buffered hydroponic coco then I would reccoment adding calcium sulfate (gypsum) as coco is lacking, and I have read trichocereus like lots of calcium. I personally buffer the coco with my own cal/mag solution by soaking the coco in the solution of1.4ec but I'm using coco in an intense hydroponic setting

[Quixote]

Lots of good info here, thanks. But I'm confused, since some of you say beware coir since it retains lots of water, others say that it is very fast draining. Which should I go by?

(as for growing cacti indoors, I sadly don't have a choice, because I live in one of the cold, dark corners of the Earth)

[GoOnThen]

My understanding is its down to particle size which then relates to the air pockets in the coir the same as any other mix. If its made up of small particles that are all the same size then very minimal amount of air can get down and through the mix and so it will dry slowly. By adding irregular shaped product to a mix like perlite, pumice, course sand ........ it will drain faster. Same happens if you use a product like coir that is made up of different size pieces and by its nature it is light and fluffy it will dry relatively fast. If you then add something like perlite to it the it will probably dry faster than a potting mix with the same amount of perlite added.

This is all based on what I know from my family working with coir and my own trials but as I have said before you must try it in your conditions as it will behave differently like most mixes under different conditions.

Cheers

Got

[franky]

Coco coir can come in the form of powder, wich is coco peat, is no where near as free draining as say a 2mm - 4mm chip size, which is seen as the ideal hydroponic pore size. I remember reading a quote from a dutch commercial rose grower, who says once the perfect pore size of coco is found for the plant, you cannot overwater them! But you can also get the coconut husks chopped up, which add a much larger pore size to the medium (mostly used for orchid growth or mulch

Although I believe cacti are a different ball game, personally the only cacti I have in a mix including coco is my trich pc, and I keep it wet quite consistently no rot here. For my other cacti I still prefer to use a heavy mineral based mix.