How To Measure the pH of Soil or Soilless Mediums.

I have written about checking pH for hydroponics growers.  Soil growers have less problems with pH than people growing with hydroponics, but good growers also measure the soil pH to see if it in the optimum range for growing the best plants. Once you grow successfully, you need to keep trying new products and techniques. Keep testing things with scientific tests so you don’t get mired in mediocrity.

You will need to wait until your medium is dry and ready to be watered. Use the same water you use for your garden and adjust the pH to around 7.0. You must know the exact pH of the water going into your soil, so really anywhere from 6.5 – 7.0 will suffice.

Second, place your plant/container in some sort of tray to catch the runoff water, and water slowly (with your pH known water) until the water drains into the tray.

It’s the first drops of water that will give you the best reading of your soil, so make sure to water slowly. Then, remove the pot from the tray to eliminate excess water entering the tray. It is a good idea to have a second tray to put the plant into as more water drips out. Then, perform the pH test on the runoff and compare it to your initial test. (You can get pH tests kits at many places including HTGSupply.com)

The results of the runoff test will likely be lower than your starting value of 7.0. If this is the case, a small drop of 0.5 pH to 6.5 pH (example) would be ok and your soil needs no further alterations at the moment.

I would recommend doing this for all plants in your garden, but if you get about the same reading for all plants the first time you do this, you may only need to test one or two plants each time you check the pH. I’d check the pH once a month or at a minimum at the beginning of vegetative flowering stages of growth.


hillbilly said...

good dr. : i've been checking the runoff from the 2 gallon containers i grow in, full of peat-based (commercially prepared) soilless mix with my hannah combo pen i bought from jarrett at the htg store in PA (which, by the way, is THE BEST THING he ever convinced me to buy - and he helped guarantee my success using it as a novice by taking the time to to give me a VERY effective "layman's" list of key operating details). i've been taking the ph by putting the meter right into the runoff tray (after watering slowly and using the initial runoff for the sample. is this poor practice? i hope it isn't, because i've been managing ph based on these readings.

. said...

This is ok. Maybe the most important thing is to be consistent each time you check the pH.