What is pH? pH is the level of acidity in the soil or growth medium of your cannabis plants. Why is pH important? Without the proper level of pH in your soil, your cannabis plant cannot grow to its optimum level of health. The stem will have difficulty drawing nutrients up to the rest of the plant and the nutrients themselves could be damaged by an imbalance of pH.
The optimal pH balance is 7 – the pH of pure drinking water. For healthy cannabis plants in an indoor weed grow, you want the pH to remain between 6.0 to 7.0, slightly more acidic than water. Cannabis pH monitoring can be done two ways primarily: using litmus test strips or a digital pH monitoring device.
Litmus paper test strips are cheaper but have a higher margin of error. Digital monitoring devices are more expensive but tend to be more accurate.
Mix a nutrient base with water and then check the pH level. If the pH balance is a bit too acidic – let’s say, a 5.9, you can simply add some water to the mix, and it should be fine. However, if the balance is off significantly in either direction, you can use PH Up and PH Down to make the necessary adjustment.
PH Up and PH Down
This pH balancing chemical is used by many growers to bring the pH of their cannabis plants back into proper balance. If you need to lower pH, PH Down works on a ratio of 1ml to 1 gallon of water to lower pH one point. That’s about 1 teaspoon per 5 gallons of water. PH Down is incredibly strong and should be measured very carefully.
If your pH needs to be raised, you can use PH Up. In comparison, PH Up is not at all potent. It requires far more PH Up to raise pH than it does PH Down to lower pH. It takes 2-4ml per gallon of water to raise pH one point. This is approximately 3 teaspoons per 5 gallons of water.
Cannabis pH monitoring during an indoor weed grow is critical to maintaining a healthy crop. How often you monitor depends on how often you water and feed your crop. When growing your plants in soil (versus hydroponics), your pH should read between 6.0 and 7.0 both when it goes into the soil and when it drains off.
To test with litmus papers, use a vial to collect a sample of the water runoff. Dip the test strip in the water sample. Compare the color to the chart provided. If your test seems to be wildly off the mark, shake the container of the plant to mix in some oxygen and evenly distribute the water.
Once it has settled, take another sample and repeat the process. With the added oxygen from the stir, the result might be a bit off, but if it is close to normal, there’s no need to adjust. If your second reading is as bad as the first, adjust with PH UP or PH Down.
If you are using a digital pH tester pen, how you take a sample will vary. The machine will also have to be calibrated before every use. Once you have your reading, make adjustments as needed with PH Up or PH Down.
Cannabis pH monitoring is an essential practice in maintaining a healthy cannabis crop. With simple tools and consistent monitoring, your cannabis growth will be healthy and the nutrients in the soil will keep your plants strong.