Soil pH is really the soil solution or soil 'water' pH, yes, but I never had much luck with those cheap probes anyway. There are horticultural testing drops for checking the pH of solutions and also soil testing kits that use a dry reagent in a capsule. I wouldn't put too much trust in a cheap probe; maybe it tells you your pH is off when it is actually fine, or maybe it says it is high when it is actually low... either way there is that potential for needless worry, and the possibility you'll try to fix something that isn't broken.
A lot of people collect run-off to test, and I do this occasionally as well just to make note of. Not really too concerned about the pH of what is going in, but with teas I find that they always seems to end up between 5-7 after brewing anyways. If I collect run-off and use horticultural test drops on it the result is typically yellow or greenish-yellow, which corresponds to 6-6.7 and that is fine. Due to the nature of soil (which acts as a filter) I can't be so sure that is my actual soil pH but it should be close enough. If I tested some run-off and the result was orange or something (for my drops that is about 5) then I would water in a couple tablespoons per gallon of water.
Because you seem to be new at this, go ahead and test the run-off and/or your fertigation solutions for peace of mind. Get a testing kit with the capsules (more accurate) and check a sample of soil every other week or so if you wish, again for peace of mind. Keep a log of what goes in, what comes out and how the plants look, etc. if you wish. Then for your next grow you can decide for yourself how frequently you should be doing it or if all that is a complete waste of time.
I was trying not to make this so verbose but...fail.
But, rest assured that there are plenty of soil growers who allow themselves to remain blissfully ignorant of their exact soil pH. In living organics there are a bunch of good things happening in the soil that lead to nutrient acquisition even in less than perfect pH, particularly if you have a strong network of the mighty mycorrhizae (fungi) on/in your roots. Other soil biota are about as important, but there are too many of them to explain. Point is that much more goes on in soil than meets the eye, although if you look carefully you actually can see the ectomycorrhiza as a white fuzz (hyphae) which encompasses the roots and spreads out. The hyphae happen to be much better at colonizing a soil/medium for moisture and nutrients than plant roots are, so they acquire nutrients (phosphates in particular) for the plant in exchange for carbohydrates.
Bacteria (particularly aerobic bacteria) are also very important and they are present in high numbers. Certain bacteria can perform specialized tasks, like fix nitrogen from the atmosphere or decompose certain kinds of organic compounds, but because they tend to prefer alkaline environments most produce a bio-film in order to keep the pH up where they prefer it, in the rhizosphere. Simultaneously they can utilize H+ ions which will further reduce acidity. The point is that all of the life in the rhizosphere results in plant available nutrients, and a general balancing act.
And this is one of the big reasons why synthetic fertilizers, pesticides, pH Up, chlorinated water and even some things which are 'natural' are contra-indicated with organics; because they in some way, shape or form reduce biological activity or otherwise lessen the capacity for the soil to be as self sufficient as it should be.
someone just told me how to rep you guys.picked up my spirits a little from good advice and learnin how to rep the ones that deserve it.cool. as this thread mentions ph . to check my soil with my meter (two probe cheapy) i use distilled water to wet the soil ,just moist and bury the meter . the medium should b wet when i check the ph right?
are there better ways to check ph. im probably overly worried about the ph. any advice is helpful thanks.