I cannot talk about pH without mentioning alkalinity.
Two acidic solutions ph 3,
Solution A tests at a hundred ppms
Solution B tests at ten thousand ppms
Which one will burn you if you pour on your skin?
pH is only half of a chemical story we also want to know the power that solution has to change burn or do anything which helps if you understand alkalinity.
Then we can move on to buffers, soil is buffered which non technically means if you add acid or alkaline solutions to it the soil will neutralise this. The soil life is also a buffer and soil has a cation exchange so it can hold or release elements too.
Lime in the soil neutralises any acids, happens reasonably quickly, pour sulphuric acid on limestone and wait a while to see this type of reaction.
We can also make conjugate bases and acids that neutralise everything and again act as a buffer. This the main principle behind pH stable ferts in hydro.
a substance formed by the reversible combination of two or more others.
a mathematical value or entity having a reciprocal relation with another.
Each buffer has some type of ionisation constant, add enough of acid or alkali and you break the buffer i.e. use all its power. Soil will buffer for months no problems be hard to break or change anything especially with the low ppms we give in water and feeds.
One issue old timers found is that high water ppms are usually due to calcium and a lesser extent magnesium and at over a few hundred those regular waterings will add too much alkaline substances and push the pH too high. We simply wanted to get our water report and look at the total ppms for reference, more than 300-500 becoming problematic by the end of the grow. A ppm meter under your tap will also explain what you have to a good extent but a water report tells you exact ppms of everything in it much better.
As long as your
calmag content of water wasn't high pH was ultra irrelevant at these low ppms.
I use to be able to explain better but if your thinking of messing with soil pH the answer is don't and it's not your problem.
As to why your plant has (small) issues is just down to light wind watering and nutrition in most of these situations.
Boy did I go down many rabbit holes with humidity pH
calmag silicon etc etc etc. Once you get out of all those holes you realise what's really important and how all that pH stuff is just pointless even dangerous to growers trying to improve.
Take it with a pinch of salt I'm old and chemistry biology and physics were much stronger points years ago, no arguments from me if you do want to pH water and soil and feeds just won't solve these small issues or coincide with a positive change making you thing ph was the original problem.
