Soil PH question!

So I have seen conflicting things on the internet.

If I my water I am watering the soil with has a PH of 6.8, and the run off is 6.5. Is the soil PH 6.5 or 6.2? I have people say the run off ph IS your soil ph, while others say you need to do math to figure it out (if you water ph is 6.8 run off is 6.5, the 0.3 difference was caused by the soil meaning the ph is 6.2).

The latter does make sense, as it assumes that the soil is more acidic than the water entered, the soil lowers the ph of the water but not to the point of the soil.

If I had 6.8 going in and 6.5 coming out I'd be happy. Either way your within range. Soil ph will change over time. a little lime and that will help fluctuations. I gave up on soil ph when my meter went to hell. I make sure to give my girls oxygenated water at 6.5 and they are very happy. Good luck to ya

Soil runoff pH will give you a ballpark idea what is going on. The actual could be ± 0.5 (plus OR minus) what the test seems to indicate. pH will change a bit over time, and it can even vary a little bit from point a to point b within the rhizosphere.

Also depends how you're watering and how drastically the fertigation solution differs from the soil pH.

Thank you for the replies!

Yes I am happy with my runoff PH, and soil is now buffered with lime. I just like to get my facts straight. Thanks again!

edit: also thank you for teaching me a new word - Fertigation

Aas a side note, depending on the pots you are using, in the case of plastic pots, when the soil has dried out before watering the soil tends pull away from the plastic pot. Upon watering, the solution you pour on your plants will immediately rush down along the interior of the pot and, if checked at that point, will be very close to the actual pH of the solution. Best to allow the soil medium to become soaked, then running off, before testing pH. But as mentioned above, if you are within the range of 6.2-6.8 you should be good.

If you buffered with lime, no need to check anything.

Wet

Wetdog said:

If you buffered with lime, no need to check anything.

Wet

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Hey Wetdog.....How much lime do you add per gallon of soil? I added 1 tbsp per gallon to a 50/50 FFOF and HF blend. I knew the OF and HF were already buffered so my ph was high in the soils. How much is too much? I have read all over that people add the extra dolomite. Thanks.

greenlikemoney said:

Aas a side note, depending on the pots you are using, in the case of plastic pots, when the soil has dried out before watering the soil tends pull away from the plastic pot. Upon watering, the solution you pour on your plants will immediately rush down along the interior of the pot and, if checked at that point, will be very close to the actual pH of the solution. Best to allow the soil medium to become soaked, then running off, before testing pH. But as mentioned above, if you are within the range of 6.2-6.8 you should be good.

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I use smart pots, and water 3/8th of a gallon very slowly first, this usually gets the bottom of the smart pot moist. I wait 30 mins for water to soak in, then water the 5/8th of the gallon rest. I water with the smart pot over a large 8 quart pot and when I hear the first sign of run off that is the water i test.

Wetdog said:

If you buffered with lime, no need to check anything.

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I have heard that too, was not sure if it was true. If that is the case would you need to flush? I always water to 20% run off to get off excess salts, and with a soil buffer I never understood the point in flushing (besides nute burn and potentially prior to harvest).