Seramis, and Growstones

[PaphMadMan]

Seramis is a granular clay product. I have seen it used most often for bonsai, but I'm sure it could be useful for orchids if used correctly.

Growstones are glass, with a high moisture holding capacity while retaining aeration - both more moisture and more air than Hydroton is what the manufacturer claims. It does start out with a high pH, but the recommendation is for multiple rinses/soaks with slightly acidic water until pH is stable, then it is pH neutral. No natural buffering, so entirely dependent on water/fertilizer pH after conditioning if used alone.

[Ray]

Pretty much any medium will wick completely to the top if the evaporation rate from the top surface is slow enough. One really good idea I've seen is to make a disc out of some flexible (but not limp) plastic sheet about an inch smaller in diameter than the top of the pot, with a hole in the middle big enough for the plant, with a slit to allow you put it around the plant. You can still water it, and the evaporating water condenses on the film and drips back into the medium.

My understanding about Growstones is the opposite of PMM's. Soda lime glass is naturally alkaline. I was under the impression that they passivated it by treating it with acid before packaging, and that, over time, that passivation is reversed.

[PaphMadMan]

They do add a buffer treatment to Growstones, but for small volume home grower use the manufacturer's instructions are to soak Growstone overnight with a large volume of pH 5.5 adjusted water, drain, and flush again with pH 5.5 water before use. They say then the product should be pH stable and ready for use.

[ramonypony]

I don't use it for S/H but in my experience seramis is much better at wicking and holding water than leca. I think the small pieces would work great for masdies. Haven't used growstone but I known it is glass and seramis is clay. When Danny (MissOrchidGirl) said that they were the same she had been trying to find a comparable media for people living in the US to buy since we couldn't find seramis, she didn't actually use it. In her current setup she uses seramis in an almost S/H way since she fills a tray and lets the water wick up.

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[Tindomul]

Thanks guys. I was pretty sure Seramis was clay but got thrown off. I sure don't like the idea of having to adjust pH with chemicals etc.. Not my Masdies. Though my distilled water source consistently produces water that comes out at a pH of 5.5. So I take it Seramis is not available in the US?

[estación seca]

Your distilled water has pH 5.5 because it contains dissolved atmospheric carbon dioxide (forms carbonic acid.). But it has almost no buffering capacity, so the pH could change rapidly and unpredictably if added to a plant container.

My soft water aquarium becomes too acidic rapidly if I use rain or RO water exclusively. But adding just 10% of our alkaline, highly minreral tap water produces a stable pH.

[ramonypony]

Originally Posted by Tindomul

So I take it Seramis is not available in the US?

I don't know if links are allowed here but there is a website (search German deli) which is the only place I know of that sells it here. They only offer the small pieces.



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[Tindomul]

Originally Posted by estación seca

Your distilled water has pH 5.5 because it contains dissolved atmospheric carbon dioxide (forms carbonic acid.). But it has almost no buffering capacity, so the pH could change rapidly and unpredictably if added to a plant container.

My soft water aquarium becomes too acidic rapidly if I use rain or RO water exclusively. But adding just 10% of our alkaline, highly minreral tap water produces a stable pH.

Good point. I can't believe I never thought of that.

[estación seca]

Yes, you can post it. Somebody posted it in the past. I don't remember the name.