pH is vital for plants because at different pH’s, plants absorb different nutrients. You want to optimize the pH so that your plants can absorb as many nutrients as possible. The perfect pH is debatable, but for seedlings, we like to use 5.8 and as they age, you can gradually increase it all the way up to 6.8. Most tap water is around 7 to 7.5 so we want to bring that level down. We have a video showing how you can do this with lemons which you can view on our channel:

For this video, we’ll be using pH Down along with a pH meter to get a more precise pH level. It’s worth noting that most pH kits come with an indicator, but we find it’s much easier to just use a meter. A useful tip is instead of buying pH up or down just buy pH Down and a pH Meter. It will cost about the same money and we’ll explain why pH Up is useless.

The first thing I’m going to do is turn my pH meter on and submerge it into my unbalanced water up to this line. Wait about 10 seconds until a reading stabilizes. Once you get a reading, remember the level or write it down. Now, my water registered at 6.94, which I want to bring down about a point. Since Im bringing the pH level down, I’m going to be using pH down. To bring down a full point, it usually takes around a half a ml, but Im for the purpose of this video, Im gonna start with about a quarter.

Be careful not to get any of this directly on your hands, gloves are helpful. So here’s the first quarters, shake and mix, now read. Ok now it’s 6.61, so basically that quarter brought it down 1 third of a point. Now lets add about a quarter more, shake and now you see, its at 6.31 so Im just gonna keep incrementally add ph down until I get the level I want.

Let’s say I go overboard and bring it down to to 5.3. All you need to do is add some tap water back into it and eventually it will go back up. This is why we find pH up is useless and you will quickly find that its much easier to just add basic water. Now quickly, let me show you how to use the indicator. All you need to do is fill the vial halfway up with the water you are testing. Add 3 drops of the indicator solution and shake it until it is one solid color. Now match the color with the color on the indicator vial and it will tell you the pH.


  1. I’d like to have seen how much by volume you recommend diluting ph down to prevent nutrient precipitation.

    I see everyone say to dilute… But how much? Nobody really starts with ph down added to water unless they have worked out how much the ph will change after inoculant and nutes added.. Which can vary..

    1. like 10ml max per pint of water is what I observe to prevent milking

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