Rock wool for semi-H?

[Optimist]

I have a few large bulbophyums that I am thinking of doing semi hydroponic with a layer of lecca, and then a layer of rock wool. My older bulbo is in spagham moss, and has been wet the whole time I have had it. The bulbo is very happy in this, and it is the first time I have not "killed" a bulbo. Ray should design a flat mount type semi hydroponic tray. I found these plastic dog dishes. I have already drilled holes in them, but I think I will fill the holes with hot glue or something, and drill the new holes farther up the side. These are really nice and can be hung if you drill holes in them for a chain.

[Dollythehun]

I took your cue and did something similar with a ziplock bowl. I was going to mount in treefern pot and spag but am rethinking that.

[Optimist]

I have seen people also put these "crawling" plant (bulbo and others) in the drip trays of large plant pots.

[Dollythehun]

That makes sense but, diseases and pests? Your method is bringing mine back from the dead. I wonder if tree fern basket will allow it to stay moist enough. I read that it held moisture.

[jkofferdahl]

I avoid the use of rock wool for several reasons. First, orchids prefer acidic conditions while rock wool creates a base environment. Second, it's environmentally a nasty substance that sits in landfills and takes decades to break down. Finally, the dust from it - and a new package is going to be dusty - is about as good for you to breathe in as are coal or silicon. There are much safer and more environmentally friendly ways to maintain moisture for orchids.

[Optimist]

Dollythehun, isn't tree fern too porous? I have had orchids on tree fern mounts, and they seem like brillo pads in a way. I suppose you should make sure your plant is healthy and growing properly before starting any experiments.

JKofferdahl, I did not know that. It seems to me that lots of plants are started in rock wool. Oh well, you learn something new every day.

[Dollythehun]

You are both correct. Andy sent me a plant in a net basket of moss and it's working well, I may go that route. It is not as dry here.

I believe that plants were started in rock wool. Do some research because I believe methods have moved ahead since then. Just a thought. Wouldn't Ray be the one to ask?

[Optimist]

Originally Posted by Dollythehun

You are both correct. Andy sent me a plant in a net basket of moss and it's working well, I may go that route. It is not as dry here.

I believe that plants were started in rock wool. Do some research because I believe methods have moved ahead since then. Just a thought. Wouldn't Ray be the one to ask?

Many industrial plants are started in rock wool. When you pot up for the first time after buying the plant, you often find a little bunch of rock wool under it. My interest in rockwool is that it is like Spagham moss, but it does not break down and thus can be left indefinately. One reason plants die is constant ripping them out of their medium and repotting them. It is better to repot as little as possible. I have been advised to over pot because it means 3+ years between potting. The main reason you repot is the breakdown of medium. When you use inorganic substances you do not have to worry about break down.

[estación seca]

Overpotting works where we have low humidity. Where it's really damp the medium doesn't dry out.

[Ray]

One of the tricks to using rock wool is to manage its density. Being clumps of fibrous material, they wet easily and stay saturated. For terrestrial plants, that's no problem, but for orchids, that can suffocate the roots.

One can purchase hydrophobic and hydrophilic versions, and make your own blends, but I never was able to find that "sweet spot" for any pant, so gave up years ago.