Why Is pH Important?

So you’ve got your plants growing in whichever system you’re using, you’ve chosen the nutrients and additives, you’ve got your lights set up and there’s a bit of extraction going on. Ready to go, right?

Not quite. See it isn’t as simple as just getting your nutrient solution mixed up and feeding it to your plants. We posted previously about why EC is important to your plants, and today we’re looking at the pH. Why is it important? Well, the pH (Potential Of Hydrogen) needs to be within a specific range so your plants can actually take up the important nutrients that it is being fed.

The pH measures how acidic or alkaline a solution is. If acidic, the pH will be in the range of 0 to 6.9, whereas if alkaline it would range from 7.1 to 14. Pure water is 7.0, and classed as neutral.

Most plants prefer a slightly more acidic environment to grow in and for hydroponic applications, a range measuring between 5.8 to 6.2 is typically recommended. It should be noted however that the favoured pH will vary from plant to plant, and you may have to do a bit of experimenting to get your perfect pH.

Diagram of the pH Scale 0-14

What Happens If The pH Is Wrong?

If your nutrient solution is not within the correct pH range, your plants may lose the ability to absorb some of the essential elements that are needed for growth. It means you’ll end up with nutrient lockout and a malnourished plant that isn’t getting everything it needs to grow.

Thankfully there is a sweet spot within the pH range where all nutrients are available to the plant, and this is what you need to be aiming for. Here you can see an image showing nutrient availability through the pH scale, as well as a list of fruits/vegetables and their recommended pH range.

Kaizen pH Meter Reading 6.2

Measuring The pH Of A Nutrient Solution

One of the least expensive ways is to simply use a paper test, such as the Viresco pH Test Strips. These strips are pH sensitive and will change colour when in contact with the solution. This strip can then be compared against a colour chart, giving you an idea of the pH. Quick, easy and cheap, but these tests can be harder to read accurately.

Another option is a liquid pH testing kit such as the Growth Technology pH Test Kit. Add a few drops of the testing liquid to a small amount of your nutrient solution and watch as the colour changes. Again, this will be compared to a colour chart to check the pH. More expensive than paper test kits, but give more accurate and reliable results.

Last but not least, one of the more expensive ways to check pH is to use a digital meter such as the Kaizen pH Meter or pH Pal Plus ones. These come in a range of different styles and sizes, the most popular being the pH pen. All you need to do is simply dip the end of the pen into your nutrient solution for a few moments and very quickly you’ll get a digital pH reading. These are more accurate than trying to compare a colour against a chart however, as with all digital equipment, they do need to be looked after properly.

pH Products Including Growth Technology, Kaizen & pH Pal Plus

Keep Pens/Meters Clean & Calibrated

You must keep the electrode clean for it to keep working, and some are even required to be wet at all times. They also need to be calibrated frequently to ensure the reading you are getting is accurate using a solution like Growth Technology pH Buffer 4 & 7. If you're unsure about anything, we offer a free calibration service in-store to help you maintain your pen or meter. We think it’s always a good idea to have some paper testing kits on hand anyway, just in case you encounter problems with your other pH testing tools!

Changing The pH Of Your Solution

It might all sound a little complicated, but fear not, fixing your pH levels isn’t too difficult. As long as you keep an eye on them regularly, you shouldn’t have too much to fix at any one time. If you find that your nutrient solution is reading too low, pH Up will help to balance it out. Likewise, if your nutrient solution is too high, pH Down will bring it back to normal.

Now balancing these levels can take some precision, and you should only ever use a tiny bit of pH Up or Down at a time to avoid pushing your nutrient solution the opposite way completely. After each drop continues testing the pH to ensure that the levels are where you want them.

It should also be noted that pH Up and Down should NEVER BE MIXED together. If you find you've used too much pH Down and making it too low, never use pH Up to correct (or vice versa) as mixing the two can cause a chemical reaction and render the entire solution unusable.

Top Tip: If using a silicon supplement in your feeding regime, mix this in first as they're known to raise the pH by as much as 2.

pH Buffer 7 & Kaizen pH Pen

Just Keep An Eye On It

The important thing is that you check the pH regularly in order to catch any problems straight away. It only takes a few minutes each day, and those few minutes could save you a lot of time in the long run. You'll know exactly what is happening with your growing plants, and you'll be able to manage their needs much better. If you need any help, we're always on hand in all four of our stores.

Shop now:

pH Buffer 4 & 7

pH up & down

pH Pal+ Meter

Kaizen pH Meter