Learned My Lesson About Ph Adjustment In Organic Soil

And that lesson was: Do it every time, bucko.

I've got a history of professional indoor cultivation, but outdoor work still holds a few mysteries for me. I did my biggest outdoor grow ever this year and went with organics. However, when it came to the decision of whether to balance feed solutions and water to 6.3, I relied on that old adage I've heard so often: "Hey, relax... when you're growing in organic soil, don't worry about adjusting the pH—the soil will self-regulate."

Only problem was, this time it didn't. My tap water here is 8.2.-8.4 in the summer, and I was watering with it and using it as the water in all my feedings. Everything went well until about two weeks into flowering, when I started getting yellowing leaves and leaf drop. I believe it was due to K getting locked out by high soil pH.

I quickly realized what was happening (and I'm thankful for that) and immediately started setting all my water and solutions to 6.3. The yellowing and leaf drop stopped, and things are going to be okay, but I'm sure I lost potential yield.

This was a bit confusing because I have done a limited bit of outdoor growing in containers in the past and didn't worry about balancing pH, and this didn't happen those times. Thus lulling me into a state of false security about it this time.

Anyway, this near-disaster convinced me that controlling the pH of all input is needed even in an organic system (for me, anyway... I appreciate that a lot of people don't do it and don't have problems. But I had problems).
Last edited:
I grow organically outdoor guerrilla I'm on tje east coast n and the water is about 7.8 ph I never Phd my water I only have 3 harvest under my belt with 4 plants each years but got 2 lbs every year so far ph has never bin a issue as I've never checked it 1 time yellow does happen earlier than chem nutes because it takes a little longer to reach the roots but that's nothing a little guano tea wouldn't fix but also leaves simple die off on there own from old age but if it was a lock out sum epson salt would fix that also if your ph is high squeeze a lemon in your water

happy b

Your problems arose as you know because of the high ph of your tap water.most tap water is alot lower and is USUALLY fine for organics.i use organics and i dont ph coz im lazy but it phing in organic soil isnt such a bad idea imo.my problem was adjusting the ph without using chemicals.
Microbes go a long way to buffer PH but I have a big unhappy gal right now that will agree with you Mr. Molecule.


Premium Gardener
Are you using something to buffer pH (like lime) in your soil mix? This could be your problem.

Soil is more forgiving with pH to a point. Water at 8.0+ will definitely cause a lot of problems as you found out. Something to buffer pH like outwest mentioned is a good idea. If your water has a pH that is out of the acceptable range definitely adjust it every time before you water. I've got a friend who has a pH of 8.2 on his well and came up with an interesting idea using a dose-a-tron and pH down to adjust his irrigation water 'on the fly' when he irrigates.

It is always good to check your soil pH once in a while as well to make sure it stays in range - plants release hydrogen ions into the soil as they uptake nutrients, so soil pH will change over time.

If you need to adjust your soil pH outdoors, do it slowly and several months in advance. For example, if you suspect you have a pH issue, test it now, during the fall and apply your lime or whatever you are going to use over the winter to the soil has many months to balance out.
My well water is at 7.8 I've never had a problem 4 years strong. Threw that pH meter in the trash once I switched complete and I stress the completely part. If your using any synthetics with your organic grow you are killing all your microbes which regulate your soil life. Also did you use a pH stabilizer like dolomite lime or green sand ? This isn't new knowledge old schoolers have been doing it for years and thankfully enough I was blessed to learn from some of those guys. I don't pH inside anymore either . Not my rockwool cuts not my moms not my veg and not my bloom room. I run coco and 100% organics . If you learn how to use the soil it will make things easier and your plants will look and yield better. If you don't believe me I can throw up a few pics. Either way glad everything worked out for ya have a happy safe harvest to all !


Premium Gardener
If your soil is buffered and your water pH is between 5 and 8 you'll probably be fine. I don't own a pH pen and my plants are all in perfect health. I'm in a rural area with fluctuating water quality and have yet to have pH issues in my recycled organic soil mix.

I'm watering with compost teas every watering or every other so ph'ing would be a waste of time and money for me, since you can't test the ph of compost tea and it fluctuates. I keep my soil ph in check instead.
Thanks @Mr. Molecule

3 year old thread but I ran exactly into the same problem....growing outside in 7gallon fabric pots

Plants stopped growing and yellow leaves popped up...all due to nutrients lockout.

My water is same as yours, 8.0 to 8.5

So I pH it BEFORE making tea
I have some giants 6' plants in 40-60 gallons no-till mix, that have been getting teas in the 2-3 (red drop range), and even taking 2 gallons of 2.0 EC tea, 3 gallons of water, 50 mls Rhizo and 50 mls GH PH down, they are still in the red range on the ph meter (4 or less).

My plants though literally look like the healthiest plants you could have, 3-4" stocks on some of them. Granted I probably should have flowered them 2 months ago so there is that lol but you cant rush perfection lol...

I am going to try to balance the heavily citrus teas with lime/aerating but growth doesn't seem to be a problem and in the past I feel adding too much PH up or down, especially in cases like this isnt worth it because it effects the EC too much, end up feedind the plants 30% PH UP/DOWN per watering. I fondly remember the days of adding too much PH UP then too much PH DOWN and ending up with 3.0 EC lol... =/.