# Rockwool for Phrags



## littlefrog (Jun 8, 2012)

Years and years ago, it was popular to use rockwool for phrag medium. Do people still do this? Since I switched growing areas and my phrags are all now constantly 'wet-footed', the bark just isn't lasting long enough.

If not rockwool, then what else? I know Dot likes diatomite, but she bought all of mine and now I can't get more...


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## SlipperFan (Jun 8, 2012)

littlefrog said:


> Years and years ago, it was popular to use rockwool for phrag medium. Do people still do this? Since I switched growing areas and my phrags are all now constantly 'wet-footed', the bark just isn't lasting long enough.
> 
> If not rockwool, then what else? I know Dot likes diatomite, but she bought all of mine and now I can't get more...



 Diatomite + CHC for Phrags. I don't know what I'll do when I use up the diatomite. Probably go back to bark. I did hear a rumor that there is supposed to be a US substitute for diatomite, but nothing substantive has come from that rumor.


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## littlefrog (Jun 8, 2012)

I actually still have several bags of the small grade diatomite. But the larger size is what I would like to have...


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## naoki (Jun 9, 2012)

I got 25Lb back of UltraSorb 100% Diatomaceous Earth from CarQuest. Can I substitute this for diatomite? I bought this for Cyps. to substitute Turface.


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## Lars Pedersen (Jun 9, 2012)

Hi

I live in Denmark, growing all my plants in the windowsills.

All are in a Rockwool medium called Greenmix.

It is a mix of waterabsorbant and waterrepellant Rockwool, and perlite.

The trick is to keep it wet at all times. 

I grow only Paph's and Phrag's, and all are in Greenmix.

They all do very well.

The trick is NOT to be affraid of water. 
They MUST be keept so wet at all times, that a nice layer of moss devellop on top of the pots.
Actually it is a good guideline, to keep the mos fresh and green.


Lars


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## cnycharles (Jun 9, 2012)

I have a bag of grodan rockwool cubes that I bought to try and use mostly by itself for phal species that like to be more wet. That didn't work well, so now I use it with standard potting mixes, mostly that new zealand treated pine that lasts a long time, with a generous amount of the gro cubes. I use more of the rockwool for the phrags and they seem happy.


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## Ray (Jun 9, 2012)

Rob - you're good at giving stuff away. After more than a year of it sitting in my basement, I recently gave away the rockwool cubes you gave me!

Also, as you have such good success with catts in S/H (read your "chain saw" post at OB), I would think phrags would be a "no-brainer".

Dot (and Rob) - have you looked into "Higromite"? It is domestic diatomite that also has some volcanic ash in it. I have experimented using the coarse material in S/H pots for oncidium intergenerics, and it works pretty well.


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## biothanasis (Jun 9, 2012)

Why not use perlite?


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## littlefrog (Jun 9, 2012)

I knew I had some rockwool at some point... Wondered where it had gotten off to...

I haven't seen higromite. I do have a big pile of expanded shale (haydite) at the old house that I have played with.


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## littlefrog (Jun 9, 2012)

biothanasis said:


> Why not use perlite?



Perlite has always floated out of pots for me... Hard to keep it on one place.


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## biothanasis (Jun 9, 2012)

littlefrog said:


> Perlite has always floated out of pots for me... Hard to keep it on one place.



Oh I see...! Perhaps if mixed with a bit of gravel or leca or seramis, would be a solution, but then pots might be heavy!

I just saw that some use polyesteric fibers instead of rockwool. But probably mixed with something else to keep in place.


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## keithrs (Jun 9, 2012)

I have used higromite.... I would not use it straight, it releases alot of silicon. It's a very messy product as well.(wear a dust mask) I use it in all my mixes at about 25% vol. Edit: rock size is 1/2-1 1/4"..... May have too much air inbetween for semi hydro.

I can't compair it to standard DE because I have never used it other then in powder form. 

I saw a video or pic that I think Jerry from OL posted on there ebb and flow table for there Phrags.

Have you tried orchiata as a media yet?


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## littlefrog (Jun 9, 2012)

Orchiata is just bark... A hard bark. It will last longer than many other forms, but it still will break down. It lasts about a year in water, for me.


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## Ray (Jun 9, 2012)

1) My first experiments with S/H used straight 3/4" perlite. Had to hold it down with a layer of pebble (that eventually worked their way to the bottom). Over time, the oh-so-friable perlite generates a suffocating "sludge" at the bottom of the pot.

2) The higromite I have is abaout 1/2"-3/4" and works fine for S/H, but due to its light color (more tan than the white of Australian diatomite), it grows algae really well.

3) Rob, I unintentionally used Orchiata 5A as an S/H medium (plastic flower pot in which the bottom drainage holes were never opened, and only one in four slots in the sidewall was - I really need to be more observant), and in a year, I saw no signs of decomposition at all.


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## Brabantia (Jun 9, 2012)

I use rockwool cubes mixed 65/35 with expensed clay (irregular size balls Gold Label from Holland). I added to this mix around 10% of charcoal (same size as the rockwool cubes). A such mix is mechanically very stable and aerated. With this synthetic substrate the pH is very stable also on the contrary of substrates containing bark.


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## keithrs (Jun 9, 2012)

I grew Phrag schlimii in higromite in sh with horrible results... That when I decide sh was not for me.... For now! Evap rate was too high!


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## Ray (Jun 9, 2012)

keithrs said:


> I grew Phrag schlimii in higromite in sh with horrible results... That when I decide sh was not for me.... For now! Evap rate was too high!



1) Wouldn't you expect high evaporation rate in San Diego?

2) I would guess that higromite does not wick as well as some LECAs.

3) it's the combination of the two that determine the moisture level higher in the pot.


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## SlipperFan (Jun 9, 2012)

naoki said:


> I got 25Lb back of UltraSorb 100% Diatomaceous Earth from CarQuest. Can I substitute this for diatomite? I bought this for Cyps. to substitute Turface.


Isn't diatomaceous earth a powder? That's what I sprinkle around hostas and garden plants to keep slugs away (it has to be re-applies after rains). Diatomite is small stones.


Ray said:


> ...Dot (and Rob) - have you looked into "Higromite"? It is domestic diatomite that also has some volcanic ash in it. I have experimented using the coarse material in S/H pots for oncidium intergenerics, and it works pretty well.





littlefrog said:


> ...I haven't seen higromite. I do have a big pile of expanded shale (haydite) at the old house that I have played with.



Maybe higromite is what I had heard about (from you maybe?). I've not seen any, but I'd be interested.

Rob, you also told me about some other clay product you got at one of the Lansing area landscape supply places. I don't remember the name, but it was like small brownish stones. I still have a pailful of it, and I use it in my zygo mix.


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## littlefrog (Jun 9, 2012)

Dot - If it isn't haydite (which is grey and sometimes a bit brown), then it was long enough ago that my brain has erased the memory of it. I suppose it wouldn't hurt for me to tour the stoneyards and see what new things they have.

I think I'll try a mix of mostly LECA mixed with some rockwool cubes. Maybe 80:20? I'll try a few things, probably. I just checked the old house and I have at least 8 bags of the small diatomite... Need to figure out something to do with small diatomite before I sell that house... Of course I might never sell that house, so maybe that is a long term problem. I wonder if slugs will cross it if it is dry?


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## Erythrone (Jun 9, 2012)

I grow some Phrags in pure rockwool, like my big Grande with 21 flowers.


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## Eric Muehlbauer (Jun 9, 2012)

I tried rockwool ages ago.....maybe 15 years ago or more. Didn't grow phrags...maybe phals, some other plants. The stuff was disgusting. Got covered with slimy algae (cyanobacteria? ) which fed hoards of fungus gnats. Plants didn't like it either after about a month or two.


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## NYEric (Jun 9, 2012)

I have some Phrag seedlings in a mix of Rockwool cubes and medium size diatomite. I follow the mix shown by Orchids Limited. In a coouple of pots that sit in water it got slimy, otherwise its holding up fine. It seems that there has been a stoppage of mining diatomite and my supplier only had the small/fine size, too small.  I picked up a new media today to test, its a kind of trated glass produt that looks like pumice stone/volcanic rock. hold 8X it's weight in moisture but is more for holding air spaces with its porosity and irregular shapes.


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## keithrs (Jun 10, 2012)

Ray said:


> 1) Wouldn't you expect high evaporation rate in San Diego?
> 
> 2) I would guess that higromite does not wick as well as some LECAs.
> 
> 3) it's the combination of the two that determine the moisture level higher in the pot.



At the time I know no better and I still don't.... Lol


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## keithrs (Jun 10, 2012)

NYEric said:


> I have some Phrag seedlings in a mix of Rockwool cubes and medium size diatomite. I follow the mix shown by Orchids Limited. In a coouple of pots that sit in water it got slimy, otherwise its holding up fine. It seems that there has been a stoppage of mining diatomite and my supplier only had the small/fine size, too small.  I picked up a new media today to test, its a kind of trated glass produt that looks like pumice stone/volcanic rock. hold 8X it's weight in moisture but is more for holding air spaces with its porosity and irregular shapes.



Is it called Growstones? I have check that stuff out several years back.


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## NYEric (Jun 11, 2012)

The bag does not have any product ID!  I got it from Black Jungle, the dart frog/terrarium company.


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## SlipperFan (Jun 11, 2012)

littlefrog said:


> Dot - If it isn't haydite (which is grey and sometimes a bit brown), then it was long enough ago that my brain has erased the memory of it. I suppose it wouldn't hurt for me to tour the stoneyards and see what new things they have.
> 
> I think I'll try a mix of mostly LECA mixed with some rockwool cubes. Maybe 80:20? I'll try a few things, probably. I just checked the old house and I have at least 8 bags of the small diatomite... Need to figure out something to do with small diatomite before I sell that house... Of course I might never sell that house, so maybe that is a long term problem. I wonder if slugs will cross it if it is dry?


It isn't haydite. I remember that it was a two-syllable name: rock something or something rock?

The small diatomite might work as a slug deterrent -- I might have to try that. The small diatomite is pretty small to be used in a potting mix.



Eric Muehlbauer said:


> I tried rockwool ages ago.....maybe 15 years ago or more. Didn't grow phrags...maybe phals, some other plants. The stuff was disgusting. Got covered with slimy algae (cyanobacteria? ) which fed hoards of fungus gnats. Plants didn't like it either after about a month or two.


Me, too -- same results. But my understanding is that rockwool cubes are much different.


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## monocotman (Jun 12, 2012)

The EYOF used to grow all their phrag and odont hybrids in rockwool, with outstanding results. 
I remember Alan Moon saying that it was the only way to get enough water into the enormous flower spikes of the odonts and prevent them from collapsing
Not sure if they still do,
David
David


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## Ray (Jun 12, 2012)

SlipperFan said:


> The small diatomite might work as a slug deterrent


Probably not. it's the sharp little "spikes" on diatomaceous earth that "stab" the slugs and snails. In diatomite and pool filter DE, they are too rounded.



> ...my understanding is that rockwool cubes are much different.


You can get hydrophylic and hydrophobic rockwool. Finding the right mix to control the water retention and aeration is the key, but I have always found it to be a big PITA, so gave up.


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## SlipperFan (Jun 12, 2012)

Ray said:


> Probably not. it's the sharp little "spikes" on diatomaceous earth that "stab" the slugs and snails. In diatomite and pool filter DE, they are too rounded.
> 
> 
> You can get hydrophylic and hydrophobic rockwool. Finding the right mix to control the water retention and aeration is the key, but I have always found it to be a big PITA, so gave up.


I tried both kinds. Orchid roots hated both of them.


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## Eric Muehlbauer (Jun 12, 2012)

Diatomaceous earth is completely useless for slugs and snails. I'd watch the slugs slime their way over it as if it were wet grass. I'll stick to iron phosphate for my slugs.


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