# Growing medium



## blondie (Jan 1, 2017)

Hi 

As I have been looking at people amazing plants on here I have noticed something. A lot of people on here grow there Phrags in bark and other orgainc media.

To me this is quite strange, (I am a bit of a freak lol) I have never had a Phrag that has not been grown in Rockwool, If i have a orchid swap most of the time the orchids come to me bare root. 

So I have always used Rockwool in my growing of them, even though I am allergic to Rockwool I still use it. I have used it for growing alot of stuff, when I was working for the RHS all the Cymbidiums where grown in it. 

When I had the chance to do some work at the EYOF with working for the RHS, they grew all there Cymbidiums, Odontogloosum/Oncidiums Miltonopsis/Miltonias and the Phrags in it. 

I suppose this is also due to what you buy your orchids in first of all and, what your comfortable growing in. 
So I suppose im asking the question, is Rockwool hard to get in other countries or is it expensive, or do people find its not every good for them.

As I gorw the rest of my orchids in fir bark as it is eaiser to get and cheap to buy.

So what do you grow in and why, thought it might be an intresting topic of disccusion.


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## Erythrone (Jan 1, 2017)

Rockwool is very easy to get in North America since it is used widely for hydroponic cultures. But many folks dislike growing in it. But not me. Many years ago I decided to grow many of my plants in RW and I have amazing results with many of them.



Phragmipedium Grande_web_modifié-1 by Erythrone2, sur Flickr

That's why RW is a media I still use. I use it sometimes straight, sometimes mixed with LECA, sometimes mixed with bark, charcoal or other stuff. 

Can you tell us what kind of rockwool do you use? I use fast draining slabs that I cut in small pieces.


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## blondie (Jan 1, 2017)

I personally use 1cm cubed Rockwool from a hydroponics company that i could drive to but they deliver so I get it delivered. 

I just use it straight dont mix anything in with it, on the very odd occation is the plant dosent need repoting but the trop cubes are green and black from, alge i remove and top up with fresh rockwool.


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## mrhappyrotter (Jan 1, 2017)

My mix is mostly rockwool. One of the biggest factors that caused me to test it out initially was price. It's slightly more expensive than other mixes/ingredients UNTIL you factor in the shipping cost per volume (which is highly relevant for potting mixes). Additionally, rockwool doesn't break down, so I find I can go longer between repotting plants, so that also impacts the economics of it.

Of course, cost isn't the only consideration, but I find that wet growing Phrags in particular LOVE rockwool. And they seem to do better for longer when potted in it compared to my experiences with bark and coconut husk based mixes. Rockwool is light and airy, and it takes awhile for it (for me) to start compacting, degrading, and accumulating salts.

Now, I do mix in other ingredients, so I'm not a rockwool purist, and I don't put all my orchids (just most) in rockwool. My typical mix also contains a hefty serving of large-medium sized charcoal and perlite, plus I mix in a small amount of organic materials like chopped sphag and/or fir bark (ingredients that I view as slow release fertilizer) and other fillers as I see fit to adjust airflow and water retention.

The main thing I keep in mind is that there are almost as many different mixes as there are growers. Some things work better for some people and in different environments & growing conditions. I just know rockwool works really well for me, and the more uniformly I grow my plants, the better they do.


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## abax (Jan 1, 2017)

I think my Phrags., etc. would stay far too wet too long to
use rockwool. My humidity is usually 90% or higher and
I use Orchiata and clay pots for quick drainage and air
movement in the mix. With lots of air movement in my
gh, I find this works best for me. I've never used rw and
would rather not.


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## Brabantia (Jan 2, 2017)

blondie said:


> I personally use 1cm cubed Rockwool from a hydroponics company that i could drive to but they deliver so I get it delivered.
> 
> I just use it straight dont mix anything in with it, on the very odd occation is the plant dosent need repoting but the trop cubes are green and black from, alge i remove and top up with fresh rockwool.


I am also growing my Phrag in RW mixed with 10% white lava rock. I. dispose a thin layer of quartzite gravel at the top surface of the potting in order to avoid the green algae development. I use Gro..n RW


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## Erythrone (Jan 2, 2017)

blondie said:


> I personally use 1cm cubed Rockwool from a hydroponics company that i could drive to but they deliver so I get it delivered.



Are you talking about Grodan grow cubes? http://shop.hydroponicsfarming.com/Eco-Grodan-Stonewool-Grow-Cubes-and-Chunks-30410.htm


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## blondie (Jan 2, 2017)

Erythrone said:


> Are you talking about Grodan grow cubes? http://shop.hydroponicsfarming.com/Eco-Grodan-Stonewool-Grow-Cubes-and-Chunks-30410.htm



Yes there just called rockwool cubes in the uk lol


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## Happypaphy7 (Jan 2, 2017)

Don't you have to "treat" the rockwool every so often??
Or is it grow stone that you have to do this? Maybe both??


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## paphioboy (Jan 3, 2017)

Erythrone, that is a real grande Grande!


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## blondie (Jan 4, 2017)

Happypaphy7 said:


> Don't you have to "treat" the rockwool every so often??
> Or is it grow stone that you have to do this? Maybe both??



I have never had a problem with rockwool just flush it out like the bark mixes to sop any build ups.


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## Happypaphy7 (Jan 4, 2017)

Well, you are using it with no problem so I believe you. 
It's just that I have once read an article ( not sure where, sorry) where this grower was using certain methods to periodically "clean" out Rockwool with some kind of chemical solutions. 

I was repelled by it as it seemed like something I rather not bother with. 
I have maintained my interest and curiosity on using Rockwool in the back of my mind as it retains water well and I've seen some great examples ( I think it was mostly moist loving intermediate-cool growers like Miltoniopsis) like one phrag shown here.


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## blondie (Jan 4, 2017)

Ive personally never heard of that unless the grower was reuseing the rockwool. I through way and se new rockwool each potting.
Im personally only use it for phrags but not with other orchids.


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## Erythrone (Jan 4, 2017)

Happypaphy7 said:


> Well, you are using it with no problem so I believe you.
> It's just that I have once read an article ( not sure where, sorry) where this grower was using certain methods to periodically "clean" out Rockwool with some kind of chemical solutions.
> 
> I was repelled by it as it seemed like something I rather not bother with.
> I have maintained my interest and curiosity on using Rockwool in the back of my mind as it retains water well and I've seen some great examples ( I think it was mostly moist loving intermediate-cool growers like Miltoniopsis) like one phrag shown here.



Here is an interesting link: The author focussed on conditionning and very careful monitoring of fertiliser: http://www.orchid.or.jp/orchid/people/tanaka/cult/Brachy/enBrachy.html

Never done this for my Phrags grown in RW.


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## blondie (Jan 5, 2017)

Interesting read.

My orchids should be dead then, as I water all my phrags with tap water and I live in a hard water area throw inn fertilizers and seaweed extract and water.


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