Does Feed / Runoff pH matter in soil?

[Waira]

Did not mean to start a war here. Just a new grower that enjoys growing. I don't use cannabis, but my wife does. She deserves the best stuff I can possibly grow. I am going to continue performing "bro science" and pH'ing my water, because that has worked for me in the past. Thanks guys!

As well you should mate! Not your fault this know-nothing idiot troll came in here and crapped the carpet...he's been a problem in Sick Bay too, I was about to drop the ban hammer on him myself! That is the one place here where garbage advise is not allowed at all, and after running it for 5+ years, I know the difference just maybe,...? So please, shrug it off and get on back to the threads topic -
Funny thing about these certain types of "pioneers" and decades long growers... caught up in old myths, pseudo-science/anecdotal nonsense that they defend to the point of mania- I recall a discussion with one clown who "started growing in the '70's", and his big tip was to boil the fucking roots on the whole live plant prior to harvest because he/they thought it was going to push more good stuff into the bud- ... about the stupidest thing I have ever heard for cannabis cultivation,... I tried to explain that the plants vascular system isn't a damn boiler and heating system in an old brownstone, it doesn't function in any way like that, and that for all practical purposes ALL the terp's and cannabinoids on on the surface of the plant on buds and leaves which are totally unconnected to the vascular system... The specialized cells at the base of the trichome heads make it all right there "on site", period.... Nope, nope, Mr.collage boy, don't care what your books say, blah blah blah...
Another non cannabis example: while getting my degree in FL, we visited a 3rd generation ornamental fish farmer who in fact raised fine fish, but he was almost violently adamant that putting conch shells in certain ponds was why some produced better than others - fucking conch shells!! 2 generations of this idiocy myth, until his son who got a masters in aquaculture did some real detective work and found out why... Pop's was having none of it, so son secretly removed the conches and put in a plastic fake ones in a few ponds... come the harvest time, and again those ponds did better as usual, only this time he pulled the fake ones up and waved them at Pops, who about fired him on the spot over it! ... Nobody likes to made a fool of, especially fucking fools, but sometimes it's gotta be done......... Point is, some people cannot be reached, it's flat-earth syndrome and nothing to be done for it but to shrug, laugh and walk away....

 

[Waira]

Coco is the medium where one normally doesn't check runoff. Soil grows you check runoff.

..other way around mate! -- see below....

I have been under the impression that your feed pH as well as runoff pH is one of the most important pieces to do correctly. I have read that if your pH is not in the correct range for your medium, uptake of certain nutrients will fail. I saw a post on a forum that said your feed and runoff pH don't matter if you're growing in soil because the soil will buffer and correct the pH. Is this accurate?

:smoking: Ok now we can get back to bizz here,...
-- yes, pH going in matters hugely! True soils ( a mix of various organic and non-organic/minerals components) will have a lime source mixed in to help buffer pH (CaCO3, MgCO3 to a much lesser extent), plus the potential of what the soil microbes can help with. However, it's the carbonate (CO3- -) that's involved directly with pH buffering only... Have a look in the Infirmary forum at the Sticky articles on top and look at the Quick & Dirty Defc. Pic Depot, 2nd page toward the bottom to see the various charts, graphs and such that help explain all this some,... pH'ing beforehand helps take the burden off the soil itself to deal with pH adjusting, which has limitations in it's capacity to do so,... The plant itself plus the other biological activity in there is also a significant influencing factor on pH....
As for run-off testing of pH in soil, it's inherently inferior for many reasons and results are not to be trusted as accurate actual in-pot pH. Nothing is better than direct measuring with a good pH probe/meter (technically, meters are for liquids only, but advert's don't follow that!).... There is an "improved" r-o testing method in that same section BTW, read up on that too! It can give a rough estimate if done right,... The main problem is this: consider the analogy of a cone type coffee filter and the pot of soil itself; as you pour water above, it dissolves and carries away more and more soluble nutes as it goes down, becoming more and more concentrated as it does,... by the time it reaches the bottom as run off, it's far more loaded than anywhere else in that pot with stuff, which potentially skews the pH results badly... if you use a feed solution or even hard/pH adjusted water, it will skew results as well.... Also, the actual pH in-pot will vary some in and out of the root zone, because all the uptake/exchange and biological activity going on there... So, in a real pinch, r-o can be used to get a crude measurement of pH, but there are many sources of error in this method, including "user" error!
As mentioned by others, some soils, like TLO/LOS (true living organic/living organic), if they are the real deal and functioning rightly, pH adjusting inputs and in-pot monitoring are not needed as much if at all,.... *(well, in-pot monitoring should happen regardless IMO, because "organic" is not a panacea against potential off-pH from happening).... Only if you have very hard water, massive CaCO3 loads, is it wise to adjust or better yet, use a better water source.. Cumulative mineral build-up can cause issues down the road....
** BTW: You pH meter needs to be well cared for, or it'll give inaccurate results... proper storage solution, rinsing, and calibrating are musts or you risk getting bad readings and missing something or making matter worse not better!

Then we have so called "soilless" mediums, Pro Mix, Sunshine #4, and coco.... These are very simple mediums, first two are peat based with some lime to help buffer; coco is usually used straight, maybe inert perlite, and on occasion, some blends with other organic stuff (Royal Gold Tupur is an amended coco)... the peat stuff can be used more or less the same way as soil, but it needs feeds and supplements right away since it's devoid of nutrients, same goes for coco... However, coco is a very specialized medium with several unique properties and a lot of do's and don't's compared to peat based soilless and true soils! It's really meant to be used as a sort of hydro medium, because of it's superior water holding and draining ability... it also has a lot of fussy aspects because of it's peculiar cation exchange capacity (CEC), and this is why it's the #1 problem medium I see in Sick Bay, almost always because peep's are running it like true soil... Coco works best being feed often, with about 20% r-o each time, and never ever water alone... This is the "hydro-like" aspect of it's behavior... As it drains, it takes away excess nute salts and restores proper balances of nutes in the pot, plus is draws in fresh air as it does so... This in part is why one can grow monsters in smaller volume pots, better than anything else!
Now the bitchy parts: coco is a major Ca++ hog, Mg++ to a lesser extent... it will bind them to the particle surfaces strongly enough to keep it from the roots unless the coco is in a state of saturation, a form of buffering (not pH here), then it gives/takes as it should... this is why elevated Ca-Mg inputs are needed with coco... Straight water can mess this CEC action up. As for r-o, in coco you take pH and TDS/EC readings going in, AND coming out to monitor both pH and to see if there's any overload of nute salts in there, hence the high volume of r-o,...

If you run soil, do yourself a big favor and get some kind of quality soil pH probe... Avoid those cheapo skinny probes, multi- test units, etc., they all suck! For the money, the Accurate 8 soil pH probe is a solid choice. mine has served me very well for years now...

.... there are other brands selling the exact same unit under a different name too... Otherwise, a more $ unit operating entirely differently can be bought, like Blue Labs one; this is basically a modified pH meter with an electrode bulb, and needs the same PITA care that a regular pH meter does,... very accurate, but you don't need pH accuracy in the +/- 0.01 range frankly!

 

[AutoWonders]

..other way around mate! -- see below....

I can only say that I have seen an overwhelming amount of posts through the years that talked about coco runoff not being effective for checking run off ph. Seen many posts for soil runoff ph.

 

[Waira]

I can only say that I have seen an overwhelming amount of posts through the years that talked about coco runoff not being effective for checking run off ph. Seen many posts for soil runoff ph.

--and every coco manufacturer and how-to website I've seen says otherwise, plus every coco guru I know here... the caveat being IF the coco is being run like it should be, with consistent inputs (daily at least) that continually flush the pot out; otherwise it becomes the same situation I talked about with soil and run off testing.... A lot of Autopot users and similar systems run into the same problem... some get away with it, some don't,...