PH Advice for soil grows

First, This new site is beautiful. Thx to the owners and developers. I love it.


I have been doing a lot of reading and learning about PH, but still have a few questions. I am growing some plants in soil and some in Roots organic soiless. Both are amended with 1 tbs/per gallon dolomite lime. I am using GH Floranova (buffered) veg and bloom.

I bought a quality PH Pen from Hanna Instruments and calibrated it and learned to use it. I like it.
My tap water registers at ph 7.9
When I add my nutes to the tap water my Ph is around 6.5 - 6.7
I did a runoff test after watering with nutes and the PH read 7.0

1) I am glad to have an accurate PH reading, but do I really need to worry too much about PH of my water and nutes growing in soil/soiless?
2) I think I am happy that my nutes bring the water down to a good range without needing any PH adjustment. If I am just using plain water should I bring the PH down to 6.5 or so before watering?

It seems that to get my plain water to 6.5 I have to add what seems like ALOT of PH Down. I use Mad Farmer PH products. I have to add around 25 drops per gallon of PH down to get me to a decent range in the mid 6's. If I add ten drops I get down to 7.0

Thx for any help and advice.

The pH of the run off is just that. The pH of the run off.....not the soil!
Soil grows swing pH naturally. You water/feed and it swings one way. Then as the plant use's the moisture it swings back the other way.... If you water/feed at 6.5 and maintain some sort of living bio's in your soil with supplements or AACT tea, your good to go, as the living bio's help regulate the pH naturally. The use of the dolomite lime was the right thing to do, as that keeps the "swing" to natural levels.
Your non soil grow will begin to need a Cal/Mag supplement soon. Coco needs that, just like RO in hydro.

Mad Farmer Get Down is the best one out there. 25 drops is just about 2.5ml so that looks on track just fine.
pH the solution mixed,,,,,not the water before mixing.

That help?

Dr. Who said:

The pH of the run off is just that. The pH of the run off.....not the soil!
Soil grows swing pH naturally. You water/feed and it swings one way. Then as the plant use's the moisture it swings back the other way.... If you water/feed at 6.5 and maintain some sort of living bio's in your soil with supplements or AACT tea, your good to go, as the living bio's help regulate the pH naturally. The use of the dolomite lime was the right thing to do, as that keeps the "swing" to natural levels.
Your non soil grow will begin to need a Cal/Mag supplement soon. Coco needs that, just like RO in hydro.

Mad Farmer Get Down is the best one out there. 25 drops is just about 2.5ml so that looks on track just fine.
pH the solution mixed,,,,,not the water before mixing.

That help?

Click to expand...

if we still had rep, that'd be getting some from me..

Thanks so much.

in 14 months of growing ive never checked run-off. ph 6.4/6.5 going in and sit back and watch your "girls" grow. do you have the HM-80? if so I have the same pen and I LOVE it!! just make sure you buy more storage solution and always keep the tester moist (with the solution) and in the cap.

If you know where your plain water Ph is at and you know where your nutes Ph is at you should be in a good place. I don't adjust my Ph for my soil grow because my water is just a bit high plain. and my nutes Ph is just a little bit low. I use foxfarms. So I feed once or twice a week with the nutes and regular water the rest of the time and I have always had great results. I think it sort of evens itself out. Soil always takes time to show results of bad Ph management but if you keep it at a decent level, never going too far out of range one way or the other, you will be fine. My hydro setup is a different story. With hydro it is super critical that the Ph is on point.

I hear you Demon. I haven't tested my soil grows for years.

Dr. Who said:

The pH of the run off is just that. The pH of the run off.....not the soil!
Soil grows swing pH naturally. You water/feed and it swings one way. Then as the plant use's the moisture it swings back the other way.... If you water/feed at 6.5 and maintain some sort of living bio's in your soil with supplements or AACT tea, your good to go, as the living bio's help regulate the pH naturally. The use of the dolomite lime was the right thing to do, as that keeps the "swing" to natural levels.
Your non soil grow will begin to need a Cal/Mag supplement soon. Coco needs that, just like RO in hydro.

Mad Farmer Get Down is the best one out there. 25 drops is just about 2.5ml so that looks on track just fine.
pH the solution mixed,,,,,not the water before mixing.

That help?

Click to expand...

Me too, Great post!!

Thx everyone. Maybe my hydro store just wanted to sell me an expensive pen I find piece of mind in it however to know that my tap water is close to 8.0 and my nutes balance it out nicely. Thx for the advice.

my tap is 8.0, then goes up to 8.2-8.4 when in my 33gal water tank that's bubbles 24/7. 1ml/gal of ph down to bring an 8.0 reading to 6.5 reading.

Yes, that's about my same result. I just measured. approximately 25 drops fills 1/4 tsp which equals approximately 1.25 ml.
It seems like a lot when coming from the dropper, but I'm glad to know that I'm on target.

Since I'm using Roots Organic, is this medium more similar to soil or more similar to hydro? It seems to have qualities of both since it has Dolomite, guano, worm castings etc.. I ask this because PH may be more crucial with Roots than it is with my soil containers.

couldn't tell ya about R/O soil, I grow in FFOF. I do add 1 cup of powdered dolomite lime per 1.5cu' bag of FFOF, as well as extra perlite.