Perfect pH?

Perfect pH?

  • 5.2

    Votes: 0 0.0%
  • 5.5

    Votes: 8 10.1%
  • 5.8

    Votes: 33 41.8%
  • 6.0

    Votes: 9 11.4%
  • 6.3

    Votes: 2 2.5%
  • swing

    Votes: 27 34.2%

  • Total voters

Crazy Composer

Medicine Planter
ICMag Supporter
I would love to see the results of a cannabis grow where the pH starts at 4 and is allowed to drift upward. In my experience, this would be bad... but I certainly keep an open mind. Every hot grow I have ever seen ended with poor results, burnt leaf tips, nutrient lock, etc.

I grow in straight coco coir, and 5.5-6.0 is where I get my best results.


I would love to see the results of a cannabis grow where the pH starts at 4 and is allowed to drift upward. In my experience, this would be bad... but I certainly keep an open mind. Every hot grow I have ever seen ended with poor results, burnt leaf tips, nutrient lock, etc.

I grow in straight coco coir, and 5.5-6.0 is where I get my best results.

same here , opinions are one thing FACT is another . scrogerman has some valid points imo and if bm can back any of this up i for one would take note but i'm the same as you , everytime i've seen a grow with such a low ph level its ended prematurely or badly


Active member
I think theres a set PH range for good reason (as we know), you dont see nute makers advising any lower than around 5.2 irrc, thats about the lowest ive seen, upto 6.5 being highest(general 5.2-6.2), wouldnt be very good marketing to get that wrong would it. good post CC, was needed, lets get this thread back on track. G'luck all!


personally i grow in straight coco and start clones and seelings at 5.6 and steadily raise the ph throughout the grow usually flushing with water ph'd to 6.0 , works for me but as we know what works for one doesn't neccasarily work for another :)

I'd like to hear an outdoor growers opinion on the swing/ph issue as mother nature no doubt reeks havoc and variables upon the plants yet they survive and flourish! What are the plants surviving through out doors compared to what their doing indoors ph wise?
Look at the pH chart, 5.8 is plainly the worst stable pH. It offers the worst availability for almost every ion. It was the worst i have tested as well.

5.2-5.3 did the best for me stable, but i grow perfect plants at 3 inches of growth per day in the UC (peaking at 5 inches over 24 hours) with a swing.

BTW in the UC water is the media, so water pH IS what we are looking at.

Awesome to see this thread blow up keep it coming.


Was blind but now IC Puckbunny in Training
No one pH level allows equal absorption of all nutes. Therefore, any flat reading guarantees unbalanced feeding. Therefore, there is no perfect number. Swing pH for best results.


I didn't want to start a new thread because yours got me thinking a little..

i've tried searching a lot, but I cant find a good solid answer as to why hydroponic plants need a different ph range from soil plants? Looking at the ph chart it says the general range for phosphorus in hydro is 5.8 - 6.1. In soil it is 6.5 - 7.0. Is it just because the roots are submerged in water that the availability of nutrients changes with pH?? :dunno:
What chart?


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This is something I have been asked a million times and the simple answer in the Under current Buckets is let it swing I have always had my best UC runs with 5.3 to 6.3. I have also found that some strains do not like the system at all I have had the same strain different phenos 5 of the phenos look great and are super vigorous and 1 pheno look like shit and never really get going this has happened quiet a few times. One thing I have found if you are running vert lighting you can really push them as far as ppm's, Way to many growers use way to much ph up and down and never allow there PH to swing this is one of the biggest problems I see as I have spent countless hours getting patience rooms dialed in.In flower I have had them up to 1800 ppm with vert lighting 4 k per plant and over night the ppm's would go from 1800 to 1300 when they where boosting hard but with over head lighting I was starting them out at 250 ppm veg and only going up to 1100ppm flower (Hanna meter) they could not take any more...I have found a couple strains that can handel anything you throw at them and are a perfecet match for the UC system..Much respect to all your hard work Bro..jack


everyone who i respect that has considerably more experience with growing cannabis than myself, including some in this thread, have all recommended swing.

I remember this vividly because I realized I could relax without having to stress over having a perfect number.


Active member
I had a drop to 4.4pH in 10 days when I was gone from home. Adjusted it to 6 and left, got home 10 days later and it was 4.4 again. You would think everything would have gone to hell, but NO, it was a good crop. This made me more confused that i already was about the hole pH thing. Now I have a pH dosage system coming. And reading this tread I'm now wondering if I'm even going to use it... 150$ down the drain?
I was thinking of using it to just keep the pH from going under 5.2, not to keep it at 5.8 and looking at the chart
wouldn't 5.5pH be the best? I'm running rDWC so NO medium here to make it more confusing...
Actually wouldn't 4.5 be better than 5.8?

Wouldn't everything be better than 5.8, I'm not getting something here now, CONFUSED as hell, I should just stop reading this forum...


Rofl no such thing as a perfect ph

Rofl no such thing as a perfect ph

As far as I am concerned and by every nutrient availability chart for hydro it shows that you have 1 of 2 options for your ph and these are
1. Allow for a swing betweent 5.4-5.8 but dont try to be to perfect when readjusting your ph when it gets out of this range as adding to much extra chems can cause probs as well, also if using a lower ph its been shown that because of the swing nutrient strength ppm/ec doesnt need to be very high for instance el nino from ghs love a ec of 1.6 in flower with a ph swing .
Now Option 2
Is to sit at a ph of around 6.1 the reccommended ph for a soiless grow and allow it to get down to 5.8 and up to 6.2 but at this higher ph I have found el nino will perform exactly the same as in the ph listed above but at a ppm/ec level of 2200 2.0 ec .

This is due to the fact that in hydro different ph;s allow for greater availablity of each nutrient so your choice is to allow for a swing and go with a lighter nute strength or sit at a higher stable ph and use a higher ec both will work just fine but the second will cost a bit more in nutrients but I have found that the second system needs less daily maintenence and less all around ph adjustments per rez before changes then I would use running at lower ph's .


Doing continued and extended testing on this topic is showing now that even lower PH ranges are actually accepted. Like down in the 4 range.
Actually I have to back bio up here in ryan rileys book growing elite marijuana there is an entire chapter on how current research shows that you can get increased production from your plants by using lower ph levels and lower ppm's(osmotic pressure) allows the plant increased nutrient uptake or in otherwords they can really suck up whats in the solution easier then when the ph and ec are in the higher levels. But personally I have found keeping my rez around 5.8-6.1 works fine just a matter of dialing in the nutrient needs so my suggestion is to any new grower keep a chart listing when you see signs of tip burn and at what ppm level each week of your plants life untill you know exactly what they can tolerate and need after this each subsequent crop will only get easier , larger and tastier as you dial in exactly what your plants want from you in the enviroment you are able to provide. Of course optimal enviroment conditions will make care and yields even better but I have seen people get 2lbs off a 3 x 4 under 1k of lights with temps in the mid 80's and and no co2 addition and other people get less then 1lb off the exact same size table with 76 degree temps co2 addition bloom booster etc .
Voted for swing, have ran drip, bubbler, NFT and E&F.

I try to achieve this swing by adjusting the tank/res pH on every fill/change to about 5.3-5.5. Let it sail / it slowly rises to around 6.0-6.5 and then its top-up time again..

R/W as medium mostly, in drips and E&F some hydroton..

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