Using lava rock to pot all my orchids.

[JScott]

Originally Posted by SouthPark

JS ----- medium size scoria, maybe 10 mm to 15 mm average diameter (since some companies are less strict with their sorting, so there can be more differences in average size ..... but that's usually ok) ----- has worked well for me with mature sized catts.

I even have a big mature sized paph ----- Paph. Saint Swithin 'Jill' that has been growing excellently in that medium size scoria.

I also have a bag of smaller size scoria ----- 5 mm to 8 mm average diameter, which I use for small juvenile orchids. I grow my Phrag. Grouville in this smaller size scoria, and Phrag. Elizabeth Castle too. Both doing very well. They've been growing long enough in it for me to know that they'll continue to grow in that without issue for the long haul.

A couple of Paph. Wossner Black Wings - juvenile, but nowhere near baby size - also been growing well for quite a while in small sized scoria too.

I haven't used red scoria before, but have been thinking about trying it out.

The colour I use is grey-coloured. They locally call it 'quincan gravel' ..... pronounced kwing-kun gravel.

I have Angraecum eburneum and Dendrobium discolor, both potted 30+ years ago in scoria .... medium size. And their pot has not changed. The scoria has not changed. They just grow outdoors, in full sun, never have been manually fertilised, and watered only by garden pop-up lawn sprinklers each night. The water from the pop-up lawn sprinkler is for the lawn, but also covers these orchids and surrounding plants.

For my other orchids in scoria ----- I fertilise just once a month with a weed pump sprayer, with weak fertiliser spray. Sprayed into the media ---- lava rock that is. Then a couple of weeks later ---- a similar procedure is carried out - not with fertiliser - but with weak cal-mag instead.

Also, don't be afraid to try approaches like layering, such as big pieces along the bottom and middle of pot, and small pieces up top etc. Flexibility.

And watering the media in a chosen band around the rim of the pot (or focusing more water in the outer region) can help avoid getting the bulk of the root ball too wet (under the orchid). And even if the roots do grow out to edges of the pot, the roots will meet the more wet regions on their own terms, and maybe get used to it - or adapted to it.



I've never repotted my orchids before (for reasons of media issue that is), nor have I ever needed to flush out the scoria with water. But I think that for those that fertilise more, or they know there's a buildup of fertiliser salts, then a flush-out every once in a while could be beneficial for the orchid(s).

I know of very good orchid growers that grow some orchids in pebbles and rocks even. As long as they know what to do with their media (eg. when to water and how much to water and don't mind to follow a workable routine), then good results can definitely come.

The red scoria was used on my plants simply because that's what was available. Do you think it will make that much of a difference whether you use the red or black? I'll keep you updated on how mine are doing in the red scoria.