How to properly measure the PH of your water

Growing good cannabis won’t be obtained by  just providing some light/water and wait untill it’s ready. There are many other aspects you need to think about in order to keep your plants healthy. One aspect that we will take abou in this article is the fact that the water you give your plants shouldn’t be too acidic or basic, this will result in a plant that isn’t able to consume all nutrients it needs (which is very negative for it’s overal growth).

In order to avoid this, we will teach you how to properly measure the PH levels of water and what exact PH level to look for. We’ll also show you how to lower or raise the PH level of water if it isn’t right already. 


What are the right PH values when it comes to watering cannabis plants?

Cannabis plants are very sensitive when it comes to the water they consume. Too high PPM levels or wrong pH values can have disastrous consequences for your plant and final product. The reason for this is that different nutrients are onle able to be consumed within different PH environments, so you need to offer a pH value that covers all of these nutrients. The next image clears this up:

In this picture you can see the necessary nutrients and which PH values they need to be in in order to be consumed by your plant. I’ts important to keep the PH of your water on a level that covers (most of) these nutrients. You can see that it’s roughly between 6.0 and 6.8 where most nutrients cover each other. This is the case when you are growing in soil. If you are growing in other mediums like Hydrophonic, you should go a little lower around 5.0 – 5.5.


The pH meter

Alright, now you know what values to look for it’s time for the measurement itself. First of all you need a Ph meter. These can be found in a local store or on the internet. Make sure you get a meter to measure the PH in water and not soil. there are 2 options:

  • Electronic PH meter
  • PH test strips

When it comes to growing cannabis, we suggest you go for the electronic one as they are more pricesly which is quite important. There are expensive ones that also measure the PPM (which is pretty handy), but also cheaper ones only used for PH values. Our recommendation:

Calibrating your meter

Before you start testing your water you have to be sure that your meter is measuring correctly. You do this by calibrating the pH meter by using calibrating buffer solutions. These are liquids that come in 2 types and both contain a very precisely PH value (pH7 and pH4). So when you put the electrode of your meter in one of these liquids it should show the exact PH value of that liquid.

To do this you should first clean the electrode using demineralized water (to neutralize the PH). Then you should start by testing the 7pH buffer solution. Put the electrode of the meter in the buffer solution. If the meter doesn’t show a pH of 7, it isn’t calibrated correctly and you should turn the calibration-button (different on every meter) untill the meter shows a perfect pH of 7. Then repeat the same steps using the 4pH buffer solution and your meter is calibrated perfectly, pretty easy huh?


Measuring the pH of your water

Alright, you got your meter calibrated and you’re ready to test the tapwater of your house. So what now? Well, there is 1 more aspect you need to be aware of and thats the nutrients that you will add to your water. Many growers make this mistake:

They measure the tap water in their house (which might has a good pH). Then they add some liquid nutrients afterwards. These nutrients could really mess with the pH of your water making that first measurement totally useless (added nutrients often make the pH increase a bit).

So only measure the pH after you have added any nutrients/additives to your water!

Alright, after mixing the water and adding everything your plant needs, it’s time to really test the pH of the water! First make sure that the water is mixed well and stir it all up properly. Then, grab your calibrated meter and test the water that you’re planning the give your plants. There is a good chance that your pH got too high due  the nutrients or other additives!

What to do if the pH is not suitable for your cannabis plants?

Sometimes it happens thats your pH isn’t on the level it should be and you need to apply some changes in order to get it right. Even when your tap water is alright, the added nutrients will increase the pH and you still need to solve it.

When it comes to cannabis plants it almost never occurs that the pH of your water is to low and it needs to be increased. This is because most tapwater already contain a pretty high pH and the added nutrients will increase it even further. So you mostly have to worry about the pH being too high and find a way to get it more acidic.

So how to lower the pH of your water if it’s too high? 

In order to lower the pH of any water you need to make it more acidic. This could be done by adding a small amount of citric acid or table vinegar. When doing this you need to add just small amounts and check the pH with every step (make sure to give it a proper stir after every addition). Keep this doing untill you reach a pH of 6.0-6.8.

The main problem when using citric acid or vinegar is that it could clog up the tubes of a hydroponic installation or dripper system. In that case it’s better to choose for a product called: pH- This product contains nitric acid that won’t clog up anything and can be bought in your local gardening store/webshop.

When using pH- you should also doing it step-by-step by adding a tiny bit and measure the pH before adding more. This makes it more precisely and you’ll avoid adding too much. If it ever occurs that the pH is too low, just repeat the same steps only using the pH+ bottle.

Our pH-/Ph+ recommendation:


More tips in how to measure and manage your pH values? Leave them in a comment below!

Leave a Reply

Your email address will not be published. Required fields are marked *