Fertilizer choices and water type

[bil]

Originally Posted by Tone

I've had great luck with Miracle Grow - Orchid (course mix). It's bark pieces no longer than an inch long. It drains perfectly, but requires a bit more attention as it tends to dry out very quickly. I water my plants about 3-4 times per week to keep the bark moist.

As for water, i'm not so picky, but i often like to use the remainder of a water bottle if i haven't finished it, distilled water, and even carbonated water from my sodastream machine (i realize the CO2 in the water probably does nothing for the plant in reality, but the concept seems sound enough, lol).

Whatever you do, don't use carbonated water on any plant. I killed a plant once using the dregs from carbonated water bottles.. That stuff is a acid as anything.

[estación seca]

Carbon dioxide dissolved in water produces carbonic acid. This is the exact process producing acid rain. It has a very low pH and, as bil posted above, can damage plants. Did you ever get some carbonated beverage sprayed in your eye? Not soon forgotten.

[Tone]

Originally Posted by bil

Whatever you do, don't use carbonated water on any plant. I killed a plant once using the dregs from carbonated water bottles.. That stuff is a acid as anything.

I have a co2 tank, so I haven't run into any issues, store bought may be different. I can't say for sure if it has had a significant impact in either direction necessarily, but i've come across a few people who feel pretty strongly about using carbonated water. That said, the CO2 is likely gone by the time it's absorbed, and i doubt enough gas is given off to benefit the plant.

I can say, from testing with my 6 orchids, that temperature and watering frequency appears to be far more influential than the type water. I've found no significant differences between tap (i'm in chicago), distilled, or bottled. Though i am against the ice cube method. I don't care who tells me ice cubes are adequate means of watering, after centuries of evolution that did not include melting ice as a sole means of hydration, why start now that it's in a house?

[Ray]

The "carbonation" of pure water in equilibrium with the air results in an extremely mild acid that has almost no impact on the plant, once it interacts with the potting medium. Carbonated water, if left open to the atmosphere, will reach that same equilibrium eventually.

Acid rain was more related to sulfur compounds from fossil fuel combustion than atmospheric CO2.

[Michelle15]

So I've tried the Dyna-grow Orchid with bottled spring water and with filtered tap (I have a PUR filter, I know they don't do much but the base pH was a bit lower than straight tap water) and the pour through tend to be mid to high 6s. So is it better to be moderately acidic using the distilled water or a touch alkaline? I know I can add things to make the distilled less acidic but I'd rather not have to.
Probably getting a rain barrel this spring.

[Ray]

The spring water is likely fairly high in mineral content (that's why it tastes so good), so is well buffered.

PUR is a small deionization unit, but costly to use if you replace the filters every 25 gallons as recommended, so that was likely pretty pure, so it makes sense that the pH of the solution made with that would be more acidic.

Frankly, if the pour-through pH is in the mid-6s for all of them, I wouldn't worry about it no matter which water supply you use.

[Orchid Whisperer]

Springs have a highly variable mineral content; it depends largely on the source. I have tested spring water that was being evaluated for bottled water purposes that had total dissolved solids content in the low double digit parts per million (ppm). The company I was testing the water for considered it a source with good potential due to the low TDS and because of the right balance in mineral content. However, some springs can have TDS in the 200+ ppm range.

Like municipal water sources, spring water must be tested for quality and the information needs to be available to the public, at least in the USA. If you want to know the quality of the water, you can always look for the water testing report on the spring water company's web page.

[Ray]

Agreed.

How nice to have a natural source that low in TDS! My well water is about 125 ppm TDS, but the local geology serves it up at a pH of 4.7.

[bil]

Originally Posted by Ray

The "carbonation" of pure water in equilibrium with the air results in an extremely mild acid that has almost no impact on the plant, once it interacts with the potting medium. Carbonated water, if left open to the atmosphere, will reach that same equilibrium eventually.

Acid rain was more related to sulfur compounds from fossil fuel combustion than atmospheric CO2.

Ray, perhaps you can explain this. We used to buy carbonated water, and one day, I was concerned about the fish in the pond, so I wanted to leave a sample for a friend to test, because I had run out of pH test. The only bottle available was one of those carbonated water bottles, made of plastic.

Not being an idiot, I washed it out thoroughly in tap water (Very hard) and then I washed it out a couple of times with pond water before half filling it with pond water and dropping it off at my friend's house.
He phoned back later saying "I had better come over, because if the reading is correct, your fish should all be dead."
When he arrived, he tested the pond water which was about pH 8. The water in the bottle tested at well below pH6. We then rinsed it out again in pond water, part filled it and left it there while we had a coffee. Half an hour later, the pH was reading 6.

Now what I want to know is, how the hell does plastic store so many protons as that?

[Orchid Whisperer]

bil, I will make a guess.

Your fish pond water likely contains dissolved and/or suspended organic matter, dissolved gases, nutrient and microbes (bacteria, algae, protozoa, etc.).

Standard methods require analysis of pH "in the field", meaning at the source and as soon after collecting as possible. The reason is that all of the organic matter, nutrients, gases and microbes in open, circulating water exist in a natural balance.

Suddenly stop circulating that water, by placing it in a bottle, maybe removing it from sunlight, and things change. You could quickly end up with reducing conditions after an hour of storage. I don't know the buffering capacity of your water, but if the buffering capacity is low (like rain water), you can get relatively large pH changes quickly.