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If you are a soil grower the best way to know what is going on with the pH of the soil is with a good pH probe like the Accurate 8.
It is very common for soil pH to vary over time which affects the plants ability to absorb needed nutrients. Plant problems caused incorrect soil pH are probably the most common issue for new growers so monitoring soil pH regularly will help keep your grow on the right track.
If you don't have a good soil pH probe (the cheap ones sold in garden stores are a waste of money) here is the next best method to check your soil pH.
The Pour Thru Method for Testing Container Media
1. water containers to saturation (so that a few drops of water come out of the bottom of the container) with the normal irrigation water they have been receiving
2. after container has drained for one hour, place a saucer under the container
3. pour enough distilled (DI) water on the surface of the container to get 50 mL (1.5 fluid ounces) of leachate to come out of the bottom of the container (Table 1)
4. collect leachate for pH and EC testing
5. calibrate pH and EC meters
6. measure pH and EC of samples
note: don't worry if you don't have an EC meter
>>> If your runoff pH is higher than your starting (water) pH, use this equation to determine your soil pH:*
Soil pH = Runoff pH + Difference
If your runoff pH is lower than your starting pH, us this equation:
Soil pH = Runoff pH - Difference.
For example, say your the starting pH of your solution before it goes in is 6.5 and the pH of your runoff is 7.0. The difference is +0.5, so using the above equation:
Soil pH = 7.0 + 0.5*
Soil pH = 7.5
If your starting pH is 6.5 and your runoff is 6.0, your difference is -0.5 and using the above equation:
Soil pH = 6.0 - 0.5
Soil pH = 5.5
It is very common for soil pH to vary over time which affects the plants ability to absorb needed nutrients. Plant problems caused incorrect soil pH are probably the most common issue for new growers so monitoring soil pH regularly will help keep your grow on the right track.
If you don't have a good soil pH probe (the cheap ones sold in garden stores are a waste of money) here is the next best method to check your soil pH.
The Pour Thru Method for Testing Container Media
1. water containers to saturation (so that a few drops of water come out of the bottom of the container) with the normal irrigation water they have been receiving
2. after container has drained for one hour, place a saucer under the container
3. pour enough distilled (DI) water on the surface of the container to get 50 mL (1.5 fluid ounces) of leachate to come out of the bottom of the container (Table 1)
4. collect leachate for pH and EC testing
5. calibrate pH and EC meters
6. measure pH and EC of samples
note: don't worry if you don't have an EC meter
>>> If your runoff pH is higher than your starting (water) pH, use this equation to determine your soil pH:*
Soil pH = Runoff pH + Difference
If your runoff pH is lower than your starting pH, us this equation:
Soil pH = Runoff pH - Difference.
For example, say your the starting pH of your solution before it goes in is 6.5 and the pH of your runoff is 7.0. The difference is +0.5, so using the above equation:
Soil pH = 7.0 + 0.5*
Soil pH = 7.5
If your starting pH is 6.5 and your runoff is 6.0, your difference is -0.5 and using the above equation:
Soil pH = 6.0 - 0.5
Soil pH = 5.5
Last edited:
Here step into that!
...a nice find from elsewhere,... :brow:--- but good info is good info, so over it came! Many of us feel that this is a dubious method in the first place, due to several potential sources of measurement error inherent in it... but it'll do in a pinch if done with this in mind.... cross contamination of run-off sampling is a common one, so folks, use a clean, dry saucer to collect from, and ditto for the cup or whatever you test in,.... better still, let the sample sit for several minutes to let as much larger particulate matter settle to the bottom as is feasible, and test the clearer solution near the top,...make sure you're still fully submersed though!
