We measure pH on a scale from 1.0 to 14.0. Pure water has a pH of 7.0 and is considered neutral, pH below 7.0 is considered acidic and pH above 7.0 is considered alkaline.
To decrease pH, an Acid is used, normally called pH Down, while a base is used to Raise your pH, also known as pH Up. A Buffer can be used to help resist pH changes.
A difference of 1.0 pH is equal to a 10 times the increase or decrease in pH. This means, a solution with a pH of 6.0 is 10 times as acidic as a solution with a pH of 7.0. A pH difference of 2.0 is equal to a hundred times increase or decrease in pH.
pH levels while growing cannabis is very important to keep within specific limits. Constant monitoring of the pH of your nutrient mix or soil is imperative during the grow cycle.
pH will be the determining factor in how well your plants are able to absorb and intake nutrients, as well as ensure a healthy growth rate and plant development.
“How to Check the pH Level Of Cannabis”
pH can be checked in a variety of ways.
• pH Meters
• pH Test Kits
• Soil pH Meters
• Soil Test Kits
If your new to Hydroponics, we suggest starting out with a pH Test Kit, they are inexpensive and easy to use. These kits require that you collect some of your nutrient solution into a small vial, then add a few drops of Test Kit Solution and Match the color with a chart, ultimately providing you with a pH measurement. The problem with these test kits is that many nutrient solutions can change the color of your water, rendering the color strip test kit useless.
pH meters are used to measure the pH of water, nutrient solution, media and soil runoff. pH meters are a great investment and allow for years of use if maintained properly. Many meters now come with replaceable probes and we suggest the regular use of a meter storage solution, calibration solutions and probe cleaning solutions. Be sure to calibrate your meter before first use and on a regular basis after that.
Soil growers should have a pH meter specifically for soil in order to measure their pH. These meters have probes that are inserted into the soil for a reading.
Soil growers can also use a Soil Test Kit. Soil Test Kits contain a separate test for pH, nitrogen, phosphorus and potassium, and provide instant results on the condition of your soil.
“pH for Hydroponics”
Hydroponic pH should be kept between 5.5 and 6.5 but can vary slightly based on cannabis strains and other growing conditions, just be sure to find what works best for your plants, and then hover a little. This means let the pH float around from day to day in order to allow the best nutrient uptake for your marijuana plants.
When adding nutrients to your hydroponic reservoir, be sure to mix your solution thoroughly as nutrients will change your waters pH level. Checking your pH will become a regular task and should be properly maintained.
“Adjusting pH of Hydroponic Solutions”
The best products on the market are pH-up and pH-down, and are used to adjust the pH of your nutrient solution when it has moved out of range. pH-up and pH-down can be purchased at any hydroponic store.
You can even use organic items to make adjustments to your pH such as nitric, phosphoric or citric acids to lower your pH, and use potassium hydroxide to raise the pH level of your nutrient solution.
Be careful not to make drastic changes to your pH in a short amount of time, as this can create undue stress to your plants and dramatically decrease your yield.
“pH and Growing In Soil”
When growing in soil the best pH range is between 6.5 and 7.0. If you are growing in containers, a single pH reading for each container is recommended. When growing outdoors in a garden, it is best to take two or three pH measurements from different areas of the garden.
If your garden is particularly large, various adjustments around your garden may be necessary. Check the pH once every week or two.
A soil garden will get its nutrients from the soil its growing in and pH fluctuations from one area to another will be likely even in a small garden.
Nutrients will also cause a change in soil pH, and when adding fertilizer to the soil it almost always results in a more acidic pH value. In time, the amount of salts produced by the breakdown of nutrients in the soil will cause the soil to become more and more acidic, and eventually the concentration of salts in the soil will stunt the plant and cause browning out of the leaves.
As the plant gets older its roots get less efficient in routing food to their leaves. In order to avoid the build up of salts in your soil and to ensure that your plant is getting all of the nutrients it requires, you can also start foliar feeding your plant from time to time.
There are readily available Foliar Feed solutions on the market, but you can also dissolve your nutrients in water and spray your plants directly Their leaves will absorb the nutrient mix at a much faster rate than the root system will.
“Adjusting pH of Your Soil”
Dolomite Lime (calcium-magnesium carbonate) is a great way to stabilize your soil, as it works slowly and continuously to help maintain your soils pH for a few months time.
Be sure to use the Fine Size Dolomite Lime and not the larger, coarser size as it can take a year if not longer to actually start working. Dolomite Lime can be purchased at your local Hydroponics store and has been used for years to help stabilize soil pH to 7.0
If you are a container grower, add one cup of fine dolomite lime to each cubic foot of soil. Mix the dolomite lime with dry soil thoroughly, then lightly water. After watering, re-mix and wait a day or two before checking the pH.
Lowering soil pH: small amounts of composted leaves, cottonseed meal, or peat moss will lower the pH of soil.
Raising soil pH: small amounts of hardwood ashes or crushed oyster/egg shells will help to raise the soil pH. Hydrated lime can also be used to raise the pH of soil. In containers, use no more than 1/8 cup of hydrated lime per cubic foot of soil. Mix it into warm water, then apply water to the soil.
Wait at least a day or two before checking the pH level of soil after attempting to raise, lower or stabilize it. If adjustments still have to be made, use small amounts of whatever material you are using. Don’t try to adjust the pH to fast or problems could arise.