BBQ Charcoal.....

[james mickelso]

Any commercially available fertilizer is good especially in dilute strength. Most orchids in the wild exist on bird poop and dead leaves. Watering I feel is the most critical element in the growing of orchids. And watering with good water low in dissolved salts. But I do like growing in lava rock. I have never had a problem with it. I used it for over 40 years as soil for growing bonsai. It is less absorptive than spongerock and doesn't degrade at all. Santa Barbara orchid Estates grows most of their seedlings in granite rock. No bark at all. Nor moss. The media doesn't matter as much as watching your watering practices.

[Cym Ladye]

James,

Lava rock and granite rock are two entirely different forms of "rock" with different absorptive characteristics.

CL

[james mickelso]

Yes I know. The lava rock I use has myriad holes in the surface which do not go through the rock and therefore absorb a little water whereas the granite that SBOE uses has no absorptive properties at all. I use sponge rock in a ratio of one to 5 or 6 bark/charcol for it's very water retentive properties. And I apologize profusely.

[Cym Ladye]

The problem with names is that we tend to use the same one for material with different properties, as seen by the preceding clarification. Just like all apples are not the same, all lava rock is not the same. There are several different types with different properties which dramatically affect their use as a potting medium for orchids. If you plan to use a form of lava rock, learn exactly what form you are looking at, where it comes from and what its qualities are that will affect the plants you use it on.

CL

[lusenok]

Originally Posted by Cym Ladye

"My new planned substrate will be composed of the following:
Coconut Coir, Lump charcoal, Perlite, and Lava Rock as the primary component.
To be fertilized with Guano Tea, sparingly."
I have to laugh when I see the plethora of "Hobo Stews" growers are coming up with. Yes, some are predicated by the fact that some products are not available locally to a grower, but I have always adhered to the "Keep it simple" theory in the beginning.
Cym Ladye

Yes! Totally agree with you!

I laugh when I see ads from repotme where they sell different mixes for each variety.
For instance, dendrobium mix has six components:
Medium Coconut Husk Chips, Small Coconut Husk Chips, Small Lava Rock, Small Granite Chips, Small Sponge Rock, Pea Gravel
Oncidium mix has 5 components:
Small Coconut Husk Chips, Small Sponge Rock, Small Stalite, Small Granite Chips, Rice Hulls

For me both varieties are doing just fine in fir bark from nearby Home Depot.