Brassia & lava rock

[KarlBrown74]

Hello, new to the forums.

I recently acquired a pair of Brassia.
I repotted one in a name brand orchid mix, and I'm really not happy with how wet the mix is staying.

I keep my phal's in a mix of 75% 1/2 inch red lava rock, 25% coarse fir bark.

My question is-
Is lava rock (fine 1/4 inch) good with Brassia?
Would fine river rock be a better alternative?
I'm concerned about the coarse nature of lava rock damaging the fine roots of the brassia.

Note:
When not on display, I keep my orchids on humidity trays under grow lights.

[billc]

Hi Karl, Welcome!
Any inert substance that will not hold water would be good. Marble chips, river rock, leca, perlite, charcoal are all used. You need to create some air space in the mix so it can dry out. Some people invert a net pot to create a nice air pocket.

Bill

[WhiteRabbit]

I would think that fine lava rock should be ok. Pumice is another possibility.

I like using small inverted net pots (or other small pot, but net pots provide more air), or some styro tucked into the center of the root mass.

[james mickelso]

I like lava rock and cinder. It allows me to water nearly every day if I wasn't so lazy. River rock would be good but I doubt if you could keep it moist enough without having to water constantly. SBOE uses broken granite rock for their starters that they sell at their sales events. the lava rock I use has lots of small pores that hold water but not to the point of saturation. I use 1/2 inch or bigger. A mix I really like for my Brassia Rex 'sakata' is 1/2 inch fir bark/sponge rock/broken up charcol. Good drainage along with the ability to hold moisture (with food) for the plants roots. It dries fairly well in a short time so rot is not an issue. Here are some pics.

[euplusia]

Welcome to the board, Karl.
I am not experienced with lava rock or river rock for Brassia. But I know that not all Brassia species grow as epiphytes. Even one species- Brassia bidens- is only found growing in soil in the gran Sabana.
Personally I am now switching to add more anorganic material to the bark with better results. I would not be concerned about damaging roots.
After all I think it's a good idea and a question that makes sense.

[james mickelso]

Another advantage with using lava rock is that it is heavy. That helps keep the pot stable when planting top heavy subjects like brassias and oncids. They like to be potted in smaller than normal pots to lessen the time their roots are wet. They are ok with damp but never wet. Lava rock is also inert and due to it's dry minerasl surface it does not harbor fungus or bacteria very well. Bark, moss, spong rock, ect are always damp. They do not dry out thoroughly and that is a perfect environment for fungus/bacterias to live. Lava rock dries out completely in no time.