High pH runoff... question?

SenorSanteria

SenorSanteria

Well-Known Member
I was recently having some trouble with my plants, which I determined to be a pH issue after purchasing a digital pH meter. The water that comes out of my faucet is nearing 8. Upon realizing this, I began correcting my water with pH Down, bringing the water to 6.3-6.5 before using. Today, both of my girls (just started 12/12) were slightly wilted, so I gave them a generous watering with 6.3ph water. No nutes today. When I checked the runoff water, it was 8.1!!!

Should I not worry about this, or should I flush until the runoff is lower?
 
Florida Girl

Florida Girl

Well-Known Member
SenorSanteria said:
I was recently having some trouble with my plants, which I determined to be a pH issue after purchasing a digital pH meter. The water that comes out of my faucet is nearing 8. Upon realizing this, I began correcting my water with pH Down, bringing the water to 6.3-6.5 before using. Today, both of my girls (just started 12/12) were slightly wilted, so I gave them a generous watering with 6.3ph water. No nutes today. When I checked the runoff water, it was 8.1!!!

Should I not worry about this, or should I flush until the runoff is lower?
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Are you growing: SOIL; HYDRO; SEMI-HYDRO (Hempy...soilless but not full hydro)? Yes.. the recommended PH is different for each ;)
 
Uncle Ben

Uncle Ben

Well-Known Member
Soil needs to be buffered down with sulfur, aluminum sulfate, peat, compost etc. Soil is a powerful buffer, and a water drench with a low pH has little to no long term effect.

UB
 
Florida Girl

Florida Girl

Well-Known Member
SenorSanteria said:
My bad, I though that it would have been understood when i said i was watering... but yes... soil is my medium. :D
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LOL... the medium is never 'implied' as soilless (semi-hydro) is also watered off and on like soil ;)

With soil you only need to get the runoff down to 7.0 or under.

Don't drown your roots by flushing to get it down to an extremely low number. If you aren't seeing problems then let the plants go to the next watering and then feed them water at 6.5 PH. If you are SEEING problems now then flush now until the runoff is 6.5 - 7.0... but do so using water at 6.5 (don't use extreme low numbers to get it down).

Hope that helps :)
 
SenorSanteria

SenorSanteria

Well-Known Member
Thanks a bunch! Yes, I could see why I would need to specify my medium now, I didnt realize semi-hydro was as prevalent.

I will continue to water with pH corrected water, thanks!
 
SenorSanteria

SenorSanteria

Well-Known Member
so its been a few days, and i've been watering as normal with ph'd water. my runoff is still in the 8 zone. should i be concerned? the plants look overall healthy, but do have some minor imperfections on some leaves that i believe to be ph related. until about 2 weeks ago i was not correcting my water at all, but have since purchased a meter allowing me to check and adjust it. so the past two weeks the water has been correct but my runoff is still off. advice?
 
Uncle Ben

Uncle Ben

Well-Known Member
SenorSanteria said:
so its been a few days, and i've been watering as normal with ph'd water. my runoff is still in the 8 zone. should i be concerned? the plants look overall healthy, but do have some minor imperfections on some leaves that i believe to be ph related. until about 2 weeks ago i was not correcting my water at all, but have since purchased a meter allowing me to check and adjust it. so the past two weeks the water has been correct but my runoff is still off. advice?
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As I tried to explain, buffered water will do nothing to permanently change the pH of the soil. I gave you some solutions.

Back to basics - contrary to popular belief, cannabis is quite pH tolerant. If your meter is accurate and of good quality.....you trust its reading, then yes, 8.0 is a little high, BUT, it all depends on whether or not the plant is getting what it needs regarding the 16 essential elements. Read your plants, if they look green and healthy, then don't worry about it.

If you have "imperfections" such as copper colored dots in the leaf tissue, then you are over fertilizing most likely. Some pix taken under a flash (for color correction) would help.

UB
 
tusseltussel

tusseltussel

Well-Known Member
you need to get it down below 7 man or you will start to see the tops getting yellow in a couple weeks 6.5 ideal
 
Kriegs

Kriegs

Well-Known Member
Hey, Senor... Soil pH and water pH are only loosely related.. goes back to the buffering thing that soil has, but water generally lacks.

I found the EXACT same thing as you -- the water out of my tap is about 8.0; maybe a little higher. But, my soil pH remains squarely at 6.5, probably 'cause my soil has a fair bit of sphagnum in it. I was having some problems with my fan leaves rolling down into little tubes, but I think I may have been simply underwatering. I started giving them more generous soaks, and they've mostly come out of it.

If your plants are basically okay, I wouldn't do anything more than adjust your water down to 6.5 as you're already doing.
 
SenorSanteria

SenorSanteria

Well-Known Member
My soil has peat moss in it, but the plants are already potted in large pots- how would I go about adding a buffer to the soil if necessary? I would think most things would need to be mixed into the soil evenly?

Ill let you guys be the judges. The plants have been on 12/12 for about a week, and today is their first day I'd say theyre actually "flowering." I think they look pretty darn good overall, but I strive for perfection. I'll let the pictures speak for themselves.
 

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SenorSanteria

SenorSanteria

Well-Known Member
In the picture it looks like the tops of the plants are completely yellow- this is just an effect from the HPS lights. They are very very green. The lower leaves are where the imperfections are (which have been there since before I corrected my water pH).
 
Kriegs

Kriegs

Well-Known Member
I'm no expert, but those yellowed margins do look like potential pH-related "lock out" of one of your trace elements, perhaps either magnesium or manganese (manganese, I know, gets locked out at 8.0 and beyond). Try adding epsom salts to your waterings at 1 teaspoon per gallon, if you're confident you have other issues resolved. Check the posts at the top of this forum topic, too, and the links -- you'll find your way to some pictures that I think resemble what you're showing.

Otherwise your plants look strong.. they may just overcome the problem now that your water pH is corrected. Sorry -- don't have any formulas for mixing in sulfur, etc. once the plants are established in the pots. Hopefully, someone who does will see this thread. As for leaf damage occurring prior to fixing the problem, the plant has no way to fix this. The evidence for the "fix" is in the maintained health of the growth that happens afterward.
 
Uncle Ben

Uncle Ben

Well-Known Member
SenorSanteria said:
My soil has peat moss in it, but the plants are already potted in large pots- how would I go about adding a buffer to the soil if necessary? I would think most things would need to be mixed into the soil evenly?
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Peat moss is a powerful buffer. Alone it sits around 4.5. Soil chemistry is an issue of the sum of the parts. If you can tell me what the soil mixture is, I can guesstimate what your pH should be. I have done experiments using about 4 samples of the same soil and running pH buffered water thru them starting at about 4.5 up to 8.8 and then testing the latent runoff with a good meter. Like I said, buffered water does not have a long term effect unless it is really radical, like watering with water that is 4.2 but then you have another problem on your hands - you've just burned the sensitive root hairs.

There is something wrong with your plants but no one can put a finger on it without knowing what you started with and what you're doing on a day to day basis. First place to start would be with the plant foods you're using.

If your top leaves are yellowing, then you're giving your plants too much light and/or too little N. Less is more. A photo using a flash, overhead room lighting, HPS OFF would do wonders to see what is really going on. The necrotic dots in the mid to lower leaves are not good. If the leaves are not productive, neither will be bud your production.

Being that you're now going into flowering, it's too late to scratch in a couple of teaspoons of Flowers of Sulfur as it must first be converted into sulfites and then sulfates via microbial action to have any affect. Normally I would prescribe about 2 teaspoons in the pot your using. Aluminum sulfate will give an immediate and long term reaction as will upcanning into a soil mix using more peat, which will permanently drop the pH. BUT, I'm not sure you have a pH problem. "It's pH" mantra that folks use often when they don't know what the real problem is. Pin down the problem before you add something that can and will do more harm than good. Mg chlorosis (deficiency) shows up in the lower leaves, sometimes middle.

Good luck,
UB
 
tusseltussel

tusseltussel

Well-Known Member
Uncle Ben said:
Peat moss is a powerful buffer. Alone it sits around 4.5. Soil chemistry is an issue of the sum of the parts. If you can tell me what the soil mixture is, I can guesstimate what your pH should be. I have done experiments using about 4 samples of the same soil and running pH buffered water thru them starting at about 4.5 up to 8.8 and then testing the latent runoff with a good meter. Like I said, buffered water does not have a long term effect unless it is really radical, like watering with water that is 4.2 but then you have another problem on your hands - you've just burned the sensitive root hairs.

There is something wrong with your plants but no one can put a finger on it without knowing what you started with and what you're doing on a day to day basis. First place to start would be with the plant foods you're using.

If your top leaves are yellowing, then you're giving your plants too much light and/or too little N. Less is more. A photo using a flash, overhead room lighting, HPS OFF would do wonders to see what is really going on. The necrotic dots in the mid to lower leaves are not good. If the leaves are not productive, neither will be bud your production.

Being that you're now going into flowering, it's too late to scratch in a couple of teaspoons of Flowers of Sulfur as it must first be converted into sulfites and then sulfates via microbial action to have any affect. Normally I would prescribe about 2 teaspoons in the pot your using. Aluminum sulfate will give an immediate and long term reaction as will upcanning into a soil mix using more peat, which will permanently drop the pH. BUT, I'm not sure you have a pH problem. "It's pH" mantra that folks use often when they don't know what the real problem is. Pin down the problem before you add something that can and will do more harm than good. Mg chlorosis (deficiency) shows up in the lower leaves, sometimes middle.

Good luck,
UB
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yelowing of the tops is not always light bleaching and too little n will start at the bottom and the answer is nute lockout zink and i belive iron if i remember corectly, ph needs to be 6.5 range or these 2 elements are locked out causing yellowing of the tops and eventually death
 
SenorSanteria

SenorSanteria

Well-Known Member
Each plant is under its own 150w HPS (my flowering chamber has two, Its just by chance that I only have two plants in there right now). The plants were started with standard potting soil that contained no nutrients- not a name brand that you guys would recognize, but the important thing was that it didnt have nutes in it. To that, I added a third peat moss, and about 10% perlite, and I have some gravel at the bottom of the pots for drainage. I used this soil mix on my last grow without any problems, where my tap water was a perfect 6.5. I have since moved, and my soil has not changed, but my water is no longer from a well. Like I said before- the tops of the plant are not yellow at all... all of the new growth has been very healthy, and they have been growing much faster since my pH correction. The spotting on the leaves and whatnot all came from before the pH was corrected- so it has stopped getting worse, and I dont expect it to fix itself.

All of my growth problems were very prevalent when the pH was off. One of the plants has vegged for almost 2 months now (although to be fair, ive taken a bunch of clones from her). But as soon as I began watering with pH corrected water, the plants took off like a rocket! Im 99% sure its a pH problem causing other nutes to be locked out.
 
Silky Shagsalot

Silky Shagsalot

Well-Known Member
Uncle Ben said:
Back to basics - contrary to popular belief, cannabis is quite pH tolerant. If your meter is accurate and of good quality.....you trust its reading, then yes, 8.0 is a little high, BUT, it all depends on whether or not the plant is getting what it needs regarding the 16 essential elements. Read your plants, if they look green and healthy, then don't worry about it.
Click to expand...
Exactly!!! if the plants aren't displaying any problems, there's no reason to change anything. of course the run-off is gonna be high, it's flushing out the build-up in the medium. don't ever chase ph, there's always a reason for ph flux. find the reason, don't chase the ph though.
 
Uncle Ben

Uncle Ben

Well-Known Member
SenorSanteria said:
Each plant is under its own 150w HPS (my flowering chamber has two, Its just by chance that I only have two plants in there right now). The plants were started with standard potting soil that contained no nutrients- not a name brand that you guys would recognize, but the important thing was that it didnt have nutes in it. To that, I added a third peat moss, and about 10% perlite, and I have some gravel at the bottom of the pots for drainage.
Click to expand...
If you started with a typical potting soil (most bagged soils have a nutrient charge whether it's published or not), and you added 1/3 brown peat moss and some perlite, I guarantee you your soil's pH was below 7.0, perhaps as low as 6.0. 99% of quality potting soils have a pH below 7.0.

What pH meter are you using and are you calibrating it with fresh calibration solutions?

Since the plants, the new growth, has recovered, this is all moot anyway. The old leaves will never recover though.

Do the experiment - fill three 2 gallon pots with your potting soil, drench one with a solution running around 4.5 (you can use vinegar or some other acid to adjust down), another with distilled water and another about 9.0 (adjust up with household ammonia). Drench well, wait until tipping the pot yields only a few drops from one of the drain holes, collect those drops and meter the runoff. You must start with properly moistened soil before you run this test. Mark these pots. Water them again in a week with normal tap water and note the result.

UB
 
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