pH & vendors

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My water has a higher pH than orchids like, 7.6-8.0. I use MSU well water formula at 125 ppm N. What is the best way to lower the pH? I have some pH Decrease from an aquarium shop but am not sure that it is good for orchids. I also have a bottle of KLN from Ray. Any suggestions on lowering the pH would be appreciated (need to include ballpark amounts of whatever is suggested)?

We are going to POE next month and could use some suggestions for the best vendors for paph and phal. My growing areas are a north window and a south window.

If you look at any hydroponics store website, you'll see bottles of stuff to lower pH for horticultural use. I'm not sure if the aquarium product is ok - I wouldn't be surprised if its just fine. Perhaps someone with fishies knows....
Do you mean that your pH is that high before or after adding fertilizer?

Many Paphs will do just fine with a higher pH, especially if they are naturally lithophytes. In fact, many people add oyster shell or lime to the mix to help keep the pH up (along with the minerals they may release).

Anyway, if you want to lower the pH, fertilizer will do it (including your MSU formula, though a balanced fertilizer would lower the pH more, if I'm not mistaken). If you don't fertilize with every watering, you may decide to switch to fertilizing at 1/4 strength with every watering to keep the pH lower, and then watering with pure water once a week or so to rinse out salts that may have built up. Also, SuperThrive has a surprisingly low pH, so I use it now and then to lower pH a little.

I've heard of people adding other things to lower pH, but my tap water is pretty neutral to begin with, so I haven't tried them. A few drops of vinegar might do the trick. The pH up or pH down from hydro stores would work, and I'm sure the stuff for fish would be ok too, but I'd start by using additives that will also be beneficial for your plants.

Hope that helps :)

- Matthew Gore
The pH is that high before adding the MSU, which does lower the pH a bit. I also have some phals and fertilize every time I water. I found a post by Ray on his site in the water section and he keeps his pH btw about 5.6 & 6.1. I have one phap that gets watered with tap water every few days because it is in a bark mix and dries out quickley. As soon as it finishes blooming, I will move it to s/h, old primeagra.

How important is pH for the orchids I have?

If your pH is high is your conductivity or TDS also high? The pH you mentioned isn't as much of a problem as total salt loading. You may want to dilute your household water a bit with rain/distilled/ or RO water before adding your fertilizer. When neutralizing a high or low pH, you are also increasing the salt loading of the mixture (basic rule of chemistry), and that could be a bigger problem than pH.

But as Matt said, allot of slippers will do good at the higher pH levels (particularly the multiflorals, sequentials, brachys, and parvis).
I would not worry about your paphs unless the pH, with fertilizer, is well above 7. Paphs , for the most part, prefer something between 6.7-7.0, probably closer to 7......If you have phrags you may want to acidify your water a bit...Take care, Eric
We use vinegar to lower pH- about 1-2 Tbsp per 30 gal brings it from ~8.5 down to ~6.5. We use RO to start + a little tap water (~10-20%) and use MSU RO among others. Wouldn't recommend aquarium pH adjusters, usually have bad (for plants) salts.


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