How much growstone can be used without raising the PH too much?

[Plantcrazed101]

Hi y'all,

So I want to create a version of Ray's semi-hydro set up for environments that tend to have lower humidity specifically for plants that I never seem to be able to water enough...

I would ultimately like to use seramis and clay pellets (NOT because orchidgirl is doing it! lol) but can't get Seramis here in the states. I have Growstone, but from what I understand, it raises the PH. So, my question is: how much Growstone would you guess I could use without interfering with the PH too much? Maybe have 50% Growstone (since it wicks better and holds more water than LECA...*I think*) 50% LECA?


I know there is Turface available here which is similar to Seramis, but the Turface has particles that are too small to use along with clay pellets without running into gas exchange problems.

[katrina]

I had awful results using growstones. Most of the plants I had in them (not s/h) suffered severe root loss. A couple didn't seem to mind but most didn't like the media at all. I have it all away to someone who was going to use it in terrestrial mixes.

I also had problems w/some where I used as an additive in the mix. Personally, I won't use it w/orchids ever again.

[Plantcrazed101]

yikes! Well I have several clones of plants (not orchids) that are my guinea pigs with the growstone...so far they are looking better than ever! I use distilled water with fertilizer, from what I understand that will make the PH of the water too acidic...my plants were even showing signs of PH that was too low. So perhaps it's a solution for me? Or maybe the PH will get too high anyway?

[terryros]

I have used Growstones for over 2 years with my entire collection of Catts, Phals, Paphs, Phrags, and Miltoniopsis, but it has always been used mixed with milled sphagnum moss and a fertilizer solution that includes 5 mL/gallon of lemon juice. This combination gives very good media pH with the pour-through technique.

But, this is obviously not a semi-hydro approach because I water only every 7 days with Phrags and Miltoniopsis and every 10-12 days with Paphs, Catts, and Phals.

After multiple, thorough washings with RO water, I still find that Growstones in a container of RO water will have a pH around 7.0, which is probably too high by itself for most orchids. Maybe using lemon juice, straight citric, or something else would allow the pH of the media to be more optimal for semi-hydro. Having done SH with LECA in the past, I can see that Growstones would otherwise seem to have nice qualities for semi-hydro of at least some orchids. The issue would be the chunk size that you would use.


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[Subrosa]

I suspect you could use a lot more grow stone successfully with rupiculous Laelia and other lime lovers than you could with Phragmipedium or Dracula species.

[Plantcrazed101]

Very interesting, I wonder if a half & half combo of LECA and growstone would help lessen the PH rise.

Are there any non-decomposing products that tend to lower the PH? Maybe if there is some sort of acidic rock out there and I combine that with growstone I'll end up with a custom made PH! lol

[MattWoelfsen]

Originally Posted by Subrosa

I suspect you could use a lot more grow stone successfully with rupiculous Laelia and other lime lovers than you could with Phragmipedium or Dracula species.

You suspect correctly! I use growstone for my rupiculous Laelia, with some LECA at the bottom to give weight to the pot. They are thriving.

[Ray]

Originally Posted by Plantcrazed101

yikes! Well I have several clones of plants (not orchids) that are my guinea pigs with the growstone...so far they are looking better than ever! I use distilled water with fertilizer, from what I understand that will make the PH of the water too acidic...my plants were even showing signs of PH that was too low. So perhaps it's a solution for me? Or maybe the PH will get too high anyway?

Distilled water does not make the pH too low. If it has been exposed to the air, it will absorb carbon dioxide and form a small amount of carbonic acid. The equilibrium pH for that is about 5.8, which is just fine.

Then there is the fact that the applied solutions play a far less significant role in the medium pH (THAT'S the important factor) than do the medium itself and the plant.

Where purified water and extreme pH levels occur is when significant levels of ordinary fertilizers are added to them. Depending upon the formula, that pH swing can be huge. Even then, that doesn't necessarily mean it'll be an issue, although I'd be wary...