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What is pH?

PH is the measurement of how alkaline or acidic something is. pH is measured on a scale of 1 - 14, a pH of 7 (the pH of pure water) is considered neutral. The measurement of pH has to do with the concentration of hydrogen in the liquid. A substance with a pH of lower than 7 is considered acidic, whereas a substance with a pH higher than 7 is considered alkaline.

  

Why is pH important to Cannabis Growers

All cannabis plants require nutrients for healthy growth. They require macronutrients nitrogen, phosphorus and potassium, as well as micronutrients and minerals such as calcium, magnesium, iron, copper and more. If your plant is not able to access these nutrients, it can lead to deficiencies and other health problems.
You may be wondering what nutrients have to do with the importance of pH? Well cannabis plants can only take up nutrients within a certain pH range. In soil this pH ranges from about 6 - 7 and in hydroponics and soilless it ranges from between 5.5 - 6.5. If the pH is higher or lower than this, the plants are not able to take in nutrients, even if they are present in your growing medium. This causes nutrient deficiencies due to "nutrient lockout".
Where cannabis plants thrive in the wild, the soil is normally slightly acidic. The Home grown cannabis plant will therefore also prefer a slightly more acidic environment for the roots to thrive.

Benefits of managing pH:

• Plants are less likely to experience leaf problems or nutrient deficiencies
• Without any nutrient problems, plants can grow faster and produce bigger yields
• If you can determine whether the pH is too high or low, you can fix it before your leaves start suffering from deficiencies.

Maintaining the pH, you are helping your plant get access to all the nutrients it needs all the time. While pH is important in all types of grows, it is especially important for growers using cannabis nutrients. The way that liquid nutrients are formulated makes them highly available to plant roots, but only in the right pH range. 

   

What is the right ph?

Soil: 6.0 - 7.0 pH

When growing in soil, the optimal pH level for the root zone is between 6.0 - 7.0. There is however no set number within this range. Instead, it is actually good to allow some fluctuation within this range to support optimal nutrient absorption. For example for one watering you can set the pH to 6.2 and then the next time to 6.6. As long as the pH stays in the range of 6.0 - 7.0you should be fine. Soil is generally more forgiving when it comes to pH imbalances.

If you are growing purely organically, which means you don't feed your plants liquid nutrients, pH will be less of a problem. If you are using amended or composted soil with organic matter, the micro-organisms contained within will make the nutrients more available to the roots. Growers using standard potting mixes and liquid nutrients will need to pay more attention to pH.

Hydro/Soilless/Coco: 5.5 - 6.5 pH

The pH level when growing in hydroponic and soilless medium, like coco for example, will require a lower pH than soil. This range will be between 5.5 - 6.5. It is also important for these mediums that you allow the pH to fluctuate in the suitable range to support nutrient uptake. These types of mediums are less forgiving than soil. Inert mediums in hydro and soilless grows

simply retain water and help keep the plant in place. You as the grower are directly in charge of providing nutrients directly to the plants roots, which means pH fluctuations are more of a risk than in soil. You will need t be extra careful not to go overboard with the nutrients.

  

How to Test and Adjust the pH for Cannabis Plants

Step 1: Add your nutrients or supplements to your water. Always add these first before you test pH because nutrients can change the pH of the water.

Step 2: Gently stir your water

Step 3: Test pH using either a pH pen, drops, or strips.

Step 4: Re-test to make sure pH is in the proper range.

Step 5: Water plants.

Step 6: Check your runoff. Soil or soilless growers who hand water their plants should check the pH of their runoff water to make sure it is in the proper range. As long as the pH of the runoff is in the right range, even if it is not exactly the same as the pH of the solution you put in, then you are good to go.

Hydroponic growers can test the pH of the reservoir by taking a small sample of the water and testing it. If the pH is outside the 5.5-6.5 pH range, you will need to correct the pH. Hydroponic growers can test the pH of the reservoir by taking a small sample of the water and testing it. If the pH is outside the 5.5-6.5 pH range, you will need to correct the pH.

   

How to Correct pH

If you see that your pH of your solution is off, you will need to adjust it. You can do this by using pH up or pH down products. If your pH is too high you will need to add pH down and vice versa. Start with a small amount and work your way up from there.

If the pH of your water is in the right range but the pH of the runoff is way out of range you will need to get it back to where it should be.

PH problems are sometimes to be caused by over-fertilising. This is when the plant is given too many nutrients or supplements, which builds up salts in the growing medium. If you believe this is what is causing problems, flushing the grow medium can help remove the salt build up.

Flushing means giving your plants 1-3 times the volume of its container with plain, pHed water. The flush gets rid of extra nutrients and salts. After the flush, water the plant with a light nutrient solution. It is normal for plants to start drooping after they have been flushed. The drooping will go away as soon as the medium begins to dry out. Once the top layer of grow medium has dried out, water the plants as normal and test the runoff to see of the pH has corrected itself. 

   

Adjusting pH Organically

If you are growing your cannabis plants organically, you may not want to use pH up and down for your plants. Instead, there are some organic alternatives you can use.

How to Lower pH Organically

To make your medium more acidic and bring it into the right range, you can add the following to your water before feeding:

• Lemon or Citrus juice
• Vinegar

Start with a small amount. If you add too much, you can simply add more water.

How to Raise pH Organically

To raise the pH of your feed organically, you can simply add some organic baking soda. Use a small amount at a time to make sure you don't go too far over the optimal pH range.

 

Tips for Hydroponic Growers

• It is normal for the pH to go up when the water is oxygenated.
• The pH changes as the plants use up nutrients in the water.
• It is a good idea to completely change your reservoir at least once every 1-2 weeks, especially in the flowering stage. This will help prevent many pH problems as well as a nutrient build up in the reservoir.
• Regularly test the reservoir water so that you can spot any pH problems early before they damage your plants.

  

Some Final Notes on The Importance of pH When Growing Cannabis

Having the correct pH at the roots will help plants get access to the nutrients they need. The main thing to keep in mind is that maintaining the right pH at the cannabis roots will help the plant absorb nutrients. This is because nutrients take on different forms depending on the surrounding pH. Adjusting and maintaining the pH is a quick and easy process, and your plants will love you for it.