My experiments with inorganic media

[JScott]

I have recently been experimenting with scoria and stalite. I've repotted several of my plants in these materials. The medium scoria is somewhat more coarse than the medium stalite, so I layer them with a layer of scoria in the bottom half of the pot (I mostly use bulb pans) and then I fill the top half with stalite. So far the results have been good. I'm only a few weeks in here, so it's hard to know for sure, but I'm seeing new root growth, and the plants aren't staying wet on the bottom and the middle like they did when planted in bark, and they're looking good.

I also like it, because I don't have to worry about rain. When the plants are outside for the summer, if we were expecting several days of rain, I used to have to cover the orchid racks with plastic to keep them from getting too wet and rotting. I don't have to do that now. Even if it rains every day, the pots drain well enough that they don't get soggy. So far I'm very pleased with my change of media. It's going well so far, and it is much more convenient than bark. I'll keep you posted with now things progress, but so far it is looking good.

Anybody have any time release fertilizer recommendations for inert media? I know fertilizer will be much more important growing in scoria and stalite. What do you guys use who grow in inert media?

[Leafmite]

With rock, the more it rains, the more Calcium you need to add. Calcium tends to wash right out of the rock and growing Cattleyas really need to have a constant supply. I have been putting fresh eggshells in all the pots and will be adding a source of Calcium to the watering can. When the orchids are outside, I use powdered milk--my orchids really seem to like it. Indoors, its Cali-Magic.
I have little bonsai baskets which I usually fill with Osmocote and Ironite and stick in the pots (I need to do this tomorrow). Nutricote is what everyone in my orchid society recommends and so it is probably the better choice. I use the Osmocote and Ironite as some of my other plants are very sensitive to fertilizer and these do not seem to harm the roots.

[Ray]

For some of my plants, I’ve been experimenting with an Osmocote Pro product that has a release life-span of 8-9 months at an average potting medium temperature of 70F. It also contains calcium, so that reduces the need for supplements.

[JScott]

Originally Posted by Ray

For some of my plants, I’ve been experimenting with an Osmocote Pro product that has a release life-span of 8-9 months at an average potting medium temperature of 70F. It also contains calcium, so that reduces the need for supplements.

Just a little bit ago, I ordered some more KelpMax from you, and now I've ordered the Osmocote pro, so you'll have two fun things to send to me soon instead of just one I love your stuff. You have the best stuff.

[Ray]

Thank you, Jeff.