Inorganic media

[Leafmite]

Hi!
My conditions are variable because...Ohio. In days past, we had dark, dreary, cold winters and the home would be cooler and the light would be dim (sliding glass doors, south-facing). Summers can be cool, wet, dry, hot...one never can predict them. Winter has changed, though. Now we have very sunny warm winter days which are a bit of a nightmare as it can get pretty hot in that window. I have to water the rock in the mornings when a warm winter day is predicted.
I have been using lava rock since the early 2000's. I started growing orchids sometime in the 1990's, according to photos (can tell by the ages of the kids). Before lava rock, I used bark and it would always become compacted at some time during the winter and my orchids would be rootless by spring (somehow they would survive to sufer another winter). Lava rock was a game changer. Until recently, the landscaping lava rock was what i always used. The landscaping lava rock is nice because it can be found everywhere, a large bag is CHEAP and you can sort through it and use the different sizes for different orchids (the largest pieces are great for the bottom of a pot). I used it for everything, including large Paphs (I watered them every day). I watered the Standard Cattleyas, Dendrobiums, Oncidiums, Vandas, and Angraecums twice a week in this set up. At first, I used clay pots but then moved to basket pots around 2011 (when I joined an orchid society and found them!).

I now buy much more expensive 1/4 inch lava rock on Amazon for Bonsai. It is proving to be a great medium for orchids that like NZ sphagnum moss as well as the smaller Cattleyas and Oncidiums. I hate paying so much for it but it is cheaper than the moss and lasts forever so, in the end, it is a bargain. Fortunately, most of the orchids I buy are mounted or small so I do not need to buy too much of it.

If you use the rock, as I mentioned, rinse it well outside. The one thing I do not like about it is the initial dust and that, until the roots get established and hold the orchid steady, you just do not want to move the orchids around too much as the rock can damage the roots if the orchid wriggles in the pot. Also, flush the medium well. I always let the rains do this each summer and then fertilize very lightly during the winter.

I like to experiment so I have tried many other mediums and I have to say that lava rock is my favorite (I also like mounted orchids but, well, some orchids are just easier to grow potted in my conditions). The orchid roots really grip onto it and I like never needing to change the medium. I had orchids growing in the same rock over ten years without issue.