There are numerous mixtures available and Lava rock is fine but it is heavy. For Cattleyas I am currently using treated pine bark plus perlite.
Tried Treated Pine bark plus coconut chunks and it was fine till a prolonged heavy rainfall event caused problems.
I use Lava Rock bashed into small bits with a hammer in my Tolumnia mix.
Tree Fern is best used as an orchid mount.

I use lave rock. It holds water but not for long. I like it and use it a lot. I am heavy handed with the hose. An advantage to lava rock is no rot. It will accumulate salts. But fertilizers without urea has less of a build up. Orchid plus at home depot. to get the right one look for the AOS endorsement on the package.

I also use terra cotta pots. I water every day.
Plastic pots will be a little slower to evaporate.

I have occasionally repotted acquired plants that formerly was potted with sphagnum. Cant get it all out so I have had some with sphagnum in the center surrounded by lava rock. Orchids like it. I use what I think is 1" rock.

Is the treated pinebark the same as orchiata? I have sponge rock, maybe I'll give those a try.Thanks so much arthurm.

Allymarie

"Orchiata" is treated radiata pine bark from New Zealand. The pine Bark available in Australia is also treated radiata pine bark. Treatments vary from brand to brand but the object of the exercise is to get rid of the resins in raw pine bark.
A long time ago most orchids were potted in mixtures with Fir Bark as the base material.
As for the No Urea stuff, I suspect it is a ploy to get consumers to buy expensive non urea orchid fertilizers.

Here is a link that might be useful: Old Thread re. Types of nitrogen

This post was edited by arthurm on Thu, May 8, 14 at 3:44

No urea matters in terms of longevity of the lava rock. Fertilizers with urea will build up salts faster and overuse will cause burns that won't happen without urea. And for what its worth the AOS endorses a brand called orchid plus. No urea. It is cheap. No ploy. And it works. Certainly not the only kind that works. But the no urea and lava rock make a good combination.

And lava rock in other circumstances could be a poor choice. That would hold true for all potting material.

How does lava rock compare with the little clay balls? Can't remember what it's called.

I don't remember the name of the clay balls either. I've never used them. I do know of a few growers that are very successful with them...I'd guess they hold less water.

Good morning,

I potted a few of the orchids in clay pots with lava rock.I'll try a few with orchiata and sponge rock and see how they do.I have Orchid Plus fertilizer, got it from Lowe's.I guess I'll have to water more often but the rainy season is almost here.The main thing is having my orchids potted in media that will provide good drainage.

The pellets are called aliflor or hydroton.I have some of my orchids potted in a mix of aliflor, tree fern with a little bark thrown in.I wish I could pot in bark but it doesn't hold up to the elements.

Thanks for your input.