pH for Cannabis – Hitting the sweet spot


what does it actually mean and why is it so important?
Simply put – the abbreviation ‘pH’ stands for ‘potential of hydrogen’.

pH measures on the sliding scale (of 0 -14) between highly acidic and highly basic solutions, both of which can be dangerous to your plants.  7 is  neutral(drinking water), where anything lower is considered highly acidic and anything higher is a highly basic solution.

Finding the right Balance

Finding the right pH balance is like cracking the growing code. The pH balance doesn’t only affect human beings, if it swings too far up or down the pH scale it’s going to have a serious effect on your plants. In hydroponics, plants need a very specific range of pH to make sure the roots absorb the right minerals the plant needs to make energy molecules during photosynthesis.

The pH level doesn’t change the concentration of the nutrition, but it drastically changes their availability. They might not be absorbed effectively, either too much, or too little. Both can have a hugely negative impact on your yield.

Check out the chart to see what minerals the roots absorb at different pH levels.


The Sweet Spot

A plant grown with hydroponics will flourish with an optimal pH between 5.5 – 6.0, with a real sweet spot of 5.8. Within this range, the plant can really explode, absorbing the full spectrum where minerals are concerned, meaning super yields.

Tip: pH up

– to make water more alkaline, dissolve garden lime in your water. Take it easy until you find the amount that works for you per litre.

Tip: pH down

– to make water more acidic, use white vinegar. It actually works.

While correcting pH, it is also a good time to flush your plants out with some of your newly corrected water, helping bring the soil to level.

It is a good idea to do this with oxygenated water prior to the lights going off, giving the plants a night time boost that mimics nature. Taking oxygen in at the roots and creating more root mass.

Outdoor growers and indoor soil growers have an advantage when it comes to pH. They have a greater margin of error. The colonies of microorganisms that form in organic growing matter act as buffers and filters and help keep pH between 6.5 and 7 most of the time.


The tricky bit is keeping the pH level stable.  When you’re home growing there are a lot of  factors that can affect your pH level. For example, the level of CO2 in the air at the plant’s roots can affect the pH level in the atmosphere. Check your pH with a meter often and use nutrients and/or ph up/down solution to balance to optimum range.


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