Ph of runoff on soil

I have never really checked pH before in soil. I used to 35 years ago when I did hydro and grew “GOD WEED”. For the hell of it I checked the water today.

The filtered water going in is at 6pH. I have not done a check with fertilizer yet. ppm is 13 for the filtered water.

Measured today the runoff and it was 4.8-5 pH and 561ppm on the fourth week in on 12/12 flower.

I see 90% green leaves and the 10% other leaves have a little yellowing or brown tips. Most are lower leaves so not too concerned.

Anything I should be doing???

Always check the PH and PPM after you have added the nutes also please provide a photo of plant in natural light @RAP

@Hungrybud Thanks, I will check the pH and PPM next time I add the nutes before I put on plants. I will see if I can get a pic in the next day or so.

I wont fertilize for another couple days but I can make a batch up and check ppm and Ph beforehand if it would be beneficial.


For most soils, you want the runoff pH to be between 6.2 and 6.8. At 5pH, it may be locked out of some nutrients it needs and you may end up with some deficiencies. What kind of soil do you use?

This is my first time using FF Ocean Forest as the main soil. @Sixpackdad @Hungrybud

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For starters, when you water or add nutrient solution to the soil, make sure the pH is 6.5. The pH you measure should be after you add the nutrients, if you are adding them.

But if the leaves start to show increasing problems, you could consider flushing to try to get the pH up to the 6.2 minimum. Alternatively, you can pH for the time being at 6.8 in an effort to get the pH of the runoff up during your normal watering.

What are you testing ph with?

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@dbrn32 I use this one. I Also have a 3 way meter for soil pH, moisture and light but the pH is hardly readable.


Cool, i would use those over probe styled meter.

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I would recommend calibrating those pH meters frequently. I have similar ones and they drift.


@Sixpackdad Will do. Have kit coming.

On Checking the water it is pH 6.3 and 12 for Tds. After putting in fertilizer for flowering it is pH 4.5 and 1001 for Tds. So what should I be adding to get it back to 6.5 pH before watering the plant?

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You need to add PH up, you can find it on amazon or local stores.

What schedule are you using for nutirentS?

Just got back from the nursery. They now carry Fox Farm products and pretty much have everything except pH up :neutral_face: We have high alkaline soil here so plenty of pH down. Guess I will have to order some online.

Right now I am using Superbloom as I had it when I started. 1000ppm 2-3 times a week and regular 6.5pH filtered water on the other days.

I have the FF Trio and Sledgehammer to use on the next grow in HappyFrog and Ocean Forest soil. I plan on following the schedule put out by Fox Farms.

I am going to mix a couple little batches of the FF trio today and check pH of them.

@Sixpackdad Also I used fish emulsions and seaweed extract for the veg stage and I add a bit of seaweed extract 2 times a month during flower.

Any one ever try this to raise pH?

@Sixpackdad @dbrn32 I just mixed Big Bloom and it measured at 6.0 pH so maybe I will only need the pH up for now with the superbloom. For now could I just use some pH up for aquariums? I can get it today.


I think so, but i have never tried it.

Aquarium or pond will work. Baking soda will work short term but really jumps the TDS. Not good for long term.

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So much for that idea. I just did a mix with all three of the trio and the pH was 4.6. sos I will need pH up later also.

Do you have an air pump and stone?