How does perlite effect PH?

[8182KSKUSH]

I probably have a very simple question. Here's some background info.
My Amish friend has some babies in 16oz keg cups, they look great, and are still in the "seedling" stage of life. All is well, however, when watering with RO water, adjusted to 6.8, (and even down to 6.7) the ph of the runoff still comes out at roughly 7.2-7.28? The soil is foxfarm lightwarrior, and the very bottom inch or two is solid perlite. (Hoping to aide drainage although the fflw is very light and seems pretty excellent).
After 3 waterings, nothing added to the RO except the ph down, the runoff is consistently coming out at the prior mentioned levels. Why? Does perlite have that kind of impact on ph? Is it the soil itself?
Considering that the runoff is 7.2ish, that's about a .5 point spread, which I guess means the soil ph is roughly at 7.0ish?
So should the RO water be adjusted down to 6.5ish to reach the desired soil ph, is this over thinking at this stage of the game? Or should they continue to be watered with ph adjusted RO to 6.7 6.8ish. My guess was that the perlite in the bottom was directly causing the runoff to come out higher than it actually is in the soil itself, in which case I am thinking that I should keep that in the back of the brain. Does this make any sense, a little advice, experience would be greatly appreciated. In the mean time I will continue to search the boards.:jointsmile:

8182KSKUSH Reviewed by 8182KSKUSH on 08-22-2008. How does perlite effect PH? I probably have a very simple question. Here's some background info. My Amish friend has some babies in 16oz keg cups, they look great, and are still in the "seedling" stage of life. All is well, however, when watering with RO water, adjusted to 6.8, (and even down to 6.7) the ph of the runoff still comes out at roughly 7.2-7.28? The soil is foxfarm lightwarrior, and the very bottom inch or two is solid perlite. (Hoping to aide drainage although the fflw is very light and seems pretty Rating: 5

[veggii]

well I am not sure ?? someone with more exp will know tho , but in the meantime you could put some perlite in a cup and run some water thru it and check the ph and see. I'm betting its micro nutes in the soil .. goodluck

[8182KSKUSH]

Roger that! THanks veggi, don't know why I didn't think of that. I will post my experiment with the perlite ph testing. I will just run some water through some perlite and test the runoff, then through just the soil. I will post what the results are and then maybe you or some others could help determine if the soil ph is looking good. So far the babies seem to like it and they don't appear to be showing any signs of stress, so maybe this is all worry over nuthin' much. Again in the mean time if anyone else reads this and has any wisdom to add then by all means put your 2 cents in!

[Dutch Pimp]

As far as I know...perlite is ph neutral....whatever your water ph is...it should stay the same going in...IMO....:twocents:

[8182KSKUSH]

Ah..
Well I know you know your stuff DutchPimp, and that makes sense. I am pretty sure I have read that before too. PH runoff that high in soil just caught me a little off guard, my Amish buddies limited experience has only been with soil that had significantly dropped ph. I bet you and veggi have already answered my question then. Just for shits and giggles I am going to test runoff with just perlite thought to see tomorrow, I will post my unspectacular findings.
Assuming it is the soil, then the soil ph is sitting at about 7 even? (Water in @ 6.75, runoff out @ 7.25?) Is that right? If true then the water needs to be going in @ 6.5 then, assuming the runoff comes out at that point @ 7.0, then my soil would be at 6.8ish? Is that reasonable, and ok with very young plants? Thanks again for the input.

[painretreat]

Hey 8KS, interesting. Your question seems to be answered. I think I read a bit about it with Stinky's 'Donkey Dick' gro. Mite drop in there and see! Not sure. Just a thot. Or a senior moment!

Sorry no pers. mess. anymore! Since this is your thread, hope U don't mind! How is the family fishing going? Guess, we could drop a thread in parenting for that? I am interested in it! :thumbsup:

And of course, I am learning all I possibly can. So, this info helps me out! pr:hippy:

[8182KSKUSH]

Hey thanks for the post sir and the tip on Stinky's DD grow, I will check that out.
Just had a near catastrophic emergency, I mean my "Amish" friend did anyway. About an hour ago his main intake fan just failed horribly! Luckily I was near by and was able to tinker with it and got it back up and running, temps hit 90, but only for an hour or so. Phewww!
That's a great idea to start a fishing thread, or children's activities thread in the parenting forum. I will get that going unless you beat me to it. Haven't been out all week so maybe tomorrow evening we will get out there again.
Thanks again sir.
Holy shit, just saw on fox and friends right now, some little 3 or 4 year girl in NC is on, she just caught a 20 something lb flathead on a 4 foot long barbie fishing pole! How funny is that literally as I was typing this post!

[McDanger]

If you have a .5 rise in pH coming out of the soil, then your soil is probably even higher than that, I would guess at 7.5, maybe even a little higher.Once you run your test thru the soil only you will know.

[stinkyattic]

McDanger is correct! Your runoff pH is a number BETWEEN the true soil pH and the water pH. It is a measure of how your liquid and your medium interact.

[8182KSKUSH]

Um ug.
So should I be watering with an even lower ph to get my soil to 6.8? Or maybe I should just start flushing everything now to get that number down. Is all of this a potential promblem, or will the soil eventually come down on it's own. I have always had the opposite promblem prior to this, (soil to low) so this is a new one on me. My other concern is that these plants are just babies, just starting their 3rd true sets of leaves. They will be transplanted as soon as I can see some roots coming out of the bottoms/sides of the cups. Would they be ok until then, they will be going to ffof from where they are now.(fflw)
All in all, from what little I can see, the plants seem to be just fine, but I know that could all change very quickly and want to be as proactive as possible. So what would you do?
-Continue watering with ph'd RO @ 6.8?
-Flush to get the runoff reading @ around 6.5ish? (Guessing that would put the soil @ around the right mark.)
-Or just continue to water with the ph'd RO @ around 6.5ish and monitor the runoff in hopes that it'll come down?
Am I over-concerned about something that really isn't a big deal or would you say this needs to be addressed and fixed now. I am sure the right answer is to flush since that would be the biggest pain in the ass for me at the moment.(I have to get my RO from a local store machine.ug.) I was slightly concerned to flushing such young seedlings. Hopefully I will be able to get some time in there today to do some experimenting. Thanks for the input again.
I love this site.:thumbsup: