Question 
Does rainwater have the perfect or optimal Ph? What is the typical Ph for rainwater and does it vary from state to state?
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Not sure there is such a thing as the perfect PH. Perfect for soil is not perfect for coco and so on. I would imagine that PH varies depending on the pollution in the air where the rain is falling.
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Google says:
Regular rain 5-5.5
Acid rain 4
When you cut onions and it gets in your eyes 
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I believe plants like a range of pH in soil. Not a perfect value. But I’m not sure how accurate that is.
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“The pH of pure water is 7; however, there are always impurities in rainwater because it stays in equilibrium with carbon dioxide in the atmosphere. Carbon dioxide is weakly acidic, so it causes rainwater to be naturally acidic as well. This leads to a calculation of a pH of around 5.7 for rainwater, according to Harvard University.”
results via duckduckgo 
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You mean there’s conflicting information on the internet? I don’t believe it 
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If it’s wet, it’s good.
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Depending on where you are it can be slightly acid from taking up atmospheric sulphur dioxide… the soil where I am is strongly acid from sulphur deposited over thousands of years of tropical rain.
Idk if there is a ‘perfect Ph, in my experience some plants can prefer, or at least don’t suffer adversely from a strongly acid soil, while others just seem to cark it or be stunted and weak: I haven’t found anything that seems overly happy in alkaline soils, but that of course could just be my experience.
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A lot of the south of England is chalk and very alkaline, wheat and other grain producing plants grow well their.
Plants have the ability to change the soil pH to suit their needs by releasing carbs and enzymes to attract bacteria that change the soils PH.
Cannabis can do the same, only it’s usually not given the chance as people grow it inside in the minimum amount of time possible.
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Also the thing I like best about my water is that it’s consistent. I know what inputs I need without checking because I already know what it needs and in what amounts. If the pH of your rain water were to change often, and I don’t know if it would, it would be a dealbreaker for me.
I rarely check my pH because I don’t need to. Because I know.
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I grew for a year using mainly rain water thinking I wouldn’t need to PH it, it wasn’t good and caused me all kinds of problems.
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Did you ultimately start checking pH? Did it change? As per my last post I’m curious about the consistency.
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Yeah I went back to tap water as the PH did vary when I started to check it.
It seemed worse when the weather was coming up from the states, much more acidic as apposed from down from the Arctic.
I was collecting it from the run off, on my workshop roof, so that may have had some effects on it as well, with dust accumulating in the dry periods, so it’s anecdotal as to weather, pun intended lol, its accurate information.
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Fun fact, most of the Brazilian rain forest gets its minerals suplemented from the African Sarah desert wind storms, that take sand and dust up into the atmosphere and mixes with the clouds and falls in the rain on South America.
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Fun fact, here in the Toronto Harbour they built a large spit to keep silt out of the shipping lanes so they don’t have to dredge it.
They forgot to remember that the Toronto islands are fed by that silt and so those islands are now shrinking.
Edit: I like fun facts.
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The rain and snow here is a bit low in PH , I add cal mag and it raises it. I am confused as to if I should be adding Cal Mag every time , every watering , all grow… if not always I would add a bit of PH up or something to bring it up instead.
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haaahaaaaa
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Depends how much you need to add to bring it up.
To much of anything added can have a detrimental affect on how the plant absorbs nutrients, so I would go with other stuff to raise it, I use apple cider vinegar to bring mine down never need to raise it unless I go to far down, then I use potassium silica to bring it up as that takes just a small amount to raise the pH in a 5 gal bucket of water.
is this with rain or just ph readings in general? I am still trying to figure out if I should always be cal magging rain. for the cal-mag, not the Ph. Does cal-mag cause lockout? Anyone? My well is Tds of 730 so I need to master rain
The difference in PH is part of what allows nutrient transfer. Range is key, but not extreme. I grow in amended coco coir and ph targeted to 6.2, and accept values between 5.8 and 7 as my extremes.
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