As you may or may not know---soil PH should be between 6.0 and 7.0 for fast and healthy growth. That PH range will allow for fast and complete assimilation of major/minor/and micro nutrients. The following is a rough guide that will allow you to make sure your soil is in that PH range and if not, how to correct it. Most pro mix's are blended to be at 6.0 to 7.0 pH. You will need the following to test the soil PH:
Soil
Cups
PH up +
PH down -
low ppm water
PH tester
First put the soil in the cups, Then you need to mix a water solution to 6.0 pH and another one to 7 pH. Calibrate your pH pen or tester. The pour the 6.0 solution into the first cup of soil slowly and collect the run-off. Now pour the 7ph solution into the second cup of soil and check the run-off. Now check the 6.0 run-off cup and if it's below 6.0 then we will need to add some dolomite lime at the rate of 2 teaspoons per 4 liters/or gallons of soil. If the 6.0 run-off PH was above 6.0 then we need to check the run-off of the 7.0 cup.
1.---If the run-off PH of the 7.0 cup is less than or equal to 7 and the 6.0ph run-off is greater than or equal to 6 you are in the sweet spot and your soil is in the correct PH range.
2.---If the run-off of the 6.0 cup is less than 6.0 than you will need to add a little dolomite lime to raise the PH of your soil.
3.---If the PH of the run-off of the 7.0 cup is over 7 than you will need to add more peat to your soil to lower the PH of your soil.
As you can see in the pick my soil run-off of the 6.0 cup came in at 5.6 so I added 2 teaspoons of dolomite lime to 4liters of soil.