There are different types of pH meters out there. What i have seen most people do on here is flush the plants and test the run-off water. The ideal way to flush is 2-3x amount of water to soil. So if you have a 3 gallon pot then you want to flush with 6 - 9 gallons of water and then test the run-off.

Hope that helps.
whatsthatsmell Reviewed by whatsthatsmell on . pH questions So......I had some pH problems at the end of my first indoor grow.... I was using an el cheap-o pH soil meter that cost me $10.00. How should I measure my pH in the most efficient way? The soil? The water? (before it goes into the soil? after runoff?) I'm just a bit confused. I know that I'll be in soil so I'm looking for 6.5-6.6, but at what point? Rating: 5