run off

[oneaday]

hi i was just wondering if someone could set
me straight with this question, when i water
my girls i like to keep the ph of my water betweeen
5.9 and 6.1 ,
i like to keep my soil ph, between 6.5 and 7.0
if i use these soil ph readings what should i be
looking for a run off reading to be
thanks

 

[Upinsmoke535]

You want around 6.0-6.5 for a soilless mix, or 6.3-6.8 for soil.

Let's say that your runoff comes out at 6.5 from 7 going in. How did that happen? The water passed through a more acidic matrix and dropped its pH. You can assume that your true soil pH is a couple tenths of a pH point lower than the runoff in this case- I'd assume about a 6.2. If it comes out HIGHER, just go in the opposite direction. If it came out 7.5, you can assume that you need to drop down from about 7.8.

 

[Durango68]

OK, good stuff.

So, continuing the conversation..

If the PH water going in is 6.4 and the runoff is 5.8.. how do I correct the soil PH? By watering with a PH of say 7.0 until the runoff starts to trend up to 6.0 to 6.5? Or is that when you add some sort of PH correcting fertilizer to the soil?