The pH Scale – Science Meets Black Magic

You know what makes everything better? Science. That includes your gardening projects. Bear with us on this one – it’s not explosions and slow-motion cameras and black holes and invisibility cloaks, but there’s still a lot of sweet, sweet science going on in hydroponics. Science that makes your plants grow faster, bigger, and healthier.

So are we all on board with science-ing up our hydroponic gardens? Cool. Let’s start with the basics (and the acids): the pH scale.


How Does Hydroponics Work?

To understand what on earth the pH scale has to do with hydro, you need to know some of the fundamentals of hydroponics and plant growth. For those of you that are new to the game, let’s start with a quick refresher.  (You should totally still read this section because knowing is half the battle, but we won’t hold it against you if you skip on down to the next one.)

Even the newbies probably know that hydroponics is the process of growing plants in a liquid nutrient solution. Some hydro systems use just the nutrient solution and others use a growing medium like potting soil or coco coir to support the roots of the plants and provide a buffer.

Which brings us to the plants. That’s why we’re all here. If you are not here for plants, please feel free to keep reading and gain some knowledge but consider yourself warned as far as the topic goes. We don’t want you to keep reading hoping to learn about the latest skin care trend and be disappointed because you are in the wrong place. Anyway, all plants need a few basic things to get growing: light, water, a support to keep them upright, and a source of nutrients. In addition to those simple ingredients, plants need the right environment. Cacti like things dry and sunny, orchids like things more humid with lots of air flow… you get the idea. One of the conditions that can seriously affect a plant is pH. That could be the pH of soil or, in the case of hydroponics, a nutrient solution or a combination of a nutrient solution and a growing medium.

What The Hell Is The pH Scale?

If you were paying attention in high school chemistry (we don’t hold it against you if you weren’t), you may have some recollection of what exactly the pH scale is. Most simply, it’s a way to measure how acidic or basic (also known as alkaline) something is. The pH scale runs from 0 to 14; everything under 7 is acidic and everything over 7 is basic. A 7 is neutral – like pure water. A 0 is basically Xenomorph blood and a 14 is a skinny soy latte pre-ordered on a pink iPhone by someone wearing Ugg boots. If you want (boring) real-world examples, hydrochloric acid is a 0 and sodium hydroxide (also known as lye, a crucial ingredient for making Fight Club-style soap) is a 14.

For an extra science-y explanation about how pH is determined by the concentration of hydrogen ions, Google “pH scale.”

So Why Do We Care?

So, you wouldn’t want to stick your hand in a bucket of Xenomorph blood (Is there a bucket that could hold it? Someone should check with Ridley Scott.) or a bucket of lye. Plants feel the same way – if their environment is too acidic or too basic, they just can’t survive. Most importantly, the pH level determines whether the plants can absorb nutrients in the soil or liquid nutrient solution. Plants can only absorb nutrients that are in solution and in a usable form to the plant. We’re back to that damn high school chem class – that means the nutrients are absorbed in water. It the environment has the wrong pH, some macronutrients (like NPK) won’t dissolve (it’s that whole hydrogen ion thing we told you to Google) and aren’t available to the plant. In other words, the wrong pH can basically starve your garden to death and that is obviously a bad thing. On the flip side, having too low or too high of a pH can make some micronutrients more available to the plant, meaning toxic levels – also a bad thing.

Not all plants are the same – different types like different soil or nutrient liquid pHs. Whatever you’re growing, do some research into what pH is best for that particular plant. For most types of plants, a pH range of 5.5 to 6.5 is the sweet spot. Broccoli, for example, grows best at a pH between 6 and 7. On the other hand, green velvet boxwood (which we know you are all growing) is good to go up to a pH of around 8.

TL;DR; — Wrong pH = starving, sad, low-yield plants. Bad news.

One-two punch! Double down on your base nutrients with this dynamic duo
One-two punch! Double down on your base nutrients with this dynamic duo

Ok, You’ve Convinced Us, What Do We Do About It?

Glad you asked! Obviously, managing the pH of your hydro system is crucial to the success of your plants. That means you’re going to need a way to measure it. A pH meter is a good option – it’s like a thermometer for the pH scale. We recommend a handheld meter that measures both pH and EC (a Science topic for another day). The sophistication of the meter is going to vary with the price, so shop around and decide what fits your needs. Also super important: make sure you also get pH standards (usually pH of 4, 7, and 10), so you can calibrate it for accuracy. You know what they say – for good plant vibrations, do the calibrations!

Now, do some research and figure out what pH range you’re aiming for. Does your nutrient solution fall within that range? If not, don’t panic – there are ways to bump your pH level back into the sweet spot. The easiest way is to simply use a hydroponic pH balancer . Those are additives that are formulated to gently ease your nutrient solution up or down the pH scale to your plants’ happy place. See? Science is awesome. Especially when it’s mixed with a little Black Magic.


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