If the pH of your hydroponics system becomes off balance, even by the smallest of margins, it can have serious ramifications.
Depending on the growing plants, an optimal pH level is usually somewhere between 5.5 and 6.5 (slightly acidic). So if hydroponics pH keeps rising, then it definitely is a thing to worry.
If, for some reason, the pH level becomes more alkaline by rising rapidly and/or continually, the ability of the plants to take in nutrients will be severely hampered.
The nutrients are essentially the plants’ food source, so if the growing plants aren’t receiving enough nutrients, they will not grow to their full potential.
A hydroponic system can become more alkaline when the root system of the plant takes in the nutrients (which are acidic) and slowly dilutes the water.
This depletes the nutrients, which raises the pH as a result. The pH can be stabilized by adding more nutrients.
In this article, we will go over these points in a lot more detail and how to correct the problem in a few simple steps.
Table of Contents
What is pH?
pH (potential/power of hydrogen) is an indicative scale used to measure the amount of acidity or base(alkaline) that water can be.
The scale range starts at 0 and finishes at 14.
When the scale is at 7, this is the point where the water is considered neutral. If the scale is lower than 7, the water is more acidic.
If the scale is larger than 7, the water is more alkaline. If the pH of a hydroponic system drops below 5 on the scale.
The plants being grown can suffer from nutrient deficiencies. These include magnesium and calcium. Furthermore, they can succumb to copper and/or iron toxicity.
On the other hand, if the pH reaches over 6.5 for extended periods, the plants can form an iron deficiency. Maintaining a healthy balance will ensure that the plant has no issues as it attempts to grow and thrive.
Why is pH Important in Hydroponic Systems?
The ideal pH level for a hydroponics system is between 5.5-6.5, so it should be slightly acidic.
If the pH is too alkaline, it will not only cause nutrient deficiencies but also affect the ability of the plants to take in the nutrients. The nutrients used in a hydroponic system are slightly acidic.
As the plants take in these nutrients, the water slowly becomes alkaline as the acidic nature of the nutrients dilutes and therefore diminishes. This is why keeping an eye on the balance is extremely important.
Otherwise, the plants simply won’t grow. In contrast, having a pH that is too low can also cause major issues within the system. For example, it can make minerals such as iron evaporate and cause clogging in the system.
Generally, though, having a lower pH value is not so much of a problem as the nutrients can slowly bring it back up. On the other hand, having a pH value that is too high requires a bit more effort.
Why Hydroponics pH Keeps Rising (Possible Reasons)
When the pH within your hydroponic system continually rises, alarm bells should be ringing, and immediate action should be taken.
Considering a hydroponic system uses water and nutrients as its primary growth methods, it’s extremely important to ensure that the pH is well balanced at all times.
Many factors can cause the pH of your hydroponics system to rise. Let’s have a look at why hydroponics pH keeps rising in a little more detail.
Nutrient Uptake
As mentioned earlier, the nutrients used in a hydroponic system are more acidic. When the plants take up the nutrients, the acidic nature of the nutrient-filled water becomes diluted.
This leaves the solution less acidic and more alkaline. This means the pH goes from low to high over time during its process.
Using Hard/Untreated Water
Not everyone has access to clean ‘soft’ water. It’s more common that town/city water has a higher concentration of dissolved calcium or magnesium.
When these deposits are higher, the water is considered ‘hard’. These minerals usually have a higher pH value.
So using ‘hard’ water to grow plants in a hydroponics system raises the pH before the nutrients are added. Due to this, the water must be constantly tested to ensure that once the nutrients are in, the pH is still at an optimal level.
Fluctuating Temperatures
The temperature of the system’s nutrient reservoir can also have an effect on the level of the water’s pH. You may even notice a difference in pH simply by testing your tap water on several occasions. Slight differences in temperatures can affect the pH.
The reason is that oxygen and carbon dioxide are easily dissolved in water. When carbon dioxide dissolves into the water reservoir, it can form traces of carbonic acid.
As a result, the reservoir slowly heats up due to the consistent air pumping, making the built-up carbonic acid reform back to carbon dioxide before it exits the system via evaporation.
As confusing as that sounds, it means that the pH rises when there is less carbonic acid in the reservoir. So ensuring that the system is built to withstand fluctuating temperatures can help minimize the risk of this occurring.
Inorganic Vs Organic Matter
The inorganic growing media used in hydroponics can act as a cushion that can absorb nutrients before and during the times the plants take them in.
As these acidic-based nutrients are absorbed, the nutrient solution becomes diluted.
A diluted solution causes the pH to rise and become more alkaline. On the other hand, organic media generally allows the nutrients to function as they should without any hindrance.
How to Keep the Right pH Levels?
If you’re a first beginner in the world of hydroponics, checking the pH levels of your system can be daunting. Furthermore, keeping them at an optimal level can seem even more overwhelming.
It doesn’t have to be, though; as long as you understand the basic concepts, you will have no problems after the first attempt.
Firstly, testing the nutrient solution is as simple as purchasing some litmus test strips. They’re quite cheap, readily available and accurate. You don’t need to go out and get anything fancy to go through this process.
These strips usually come in a water-tight bottle and contain a built-in dye sensitive to all ranges on the pH scale. Once dipped in the nutrient solution, the dye reveals a color or number (depending on the type of kit).
This color or number can then be compared to a color shade chart that lets you know your nutrient solution’s pH.
The best way to maintain desired pH levels within your system is by only using products made for use within a hydroponic system.
You can purchase chemical solutions called ‘pH up’ and ‘pH down’ that do exactly as the name suggests. Raise and lower the pH of the nutrient solution.
Alternatively, automatic controls can be installed for more elaborate setups. In this case, you would add nutrients and/or other solutions to certain canisters released at certain times to automate the whole process.
Lastly, if your system is quite small, you can add weaker acids like vinegar or citric acid to help lower the pH.
Ammonium nitrate can also be applied, but it is stronger than the other two choices. In contrast, you can add lime water or kalkwasser to help raise the pH if it drops below 5.
You would usually use products based on 2 alkaline ingredients, either caustic potash or potassium carbonate, to help raise the pH. It’s all a matter of personal preference, design and/or budget, though.
Frequently Asked Questions (fAQs)
Can we naturally lower pH in hydroponics?
For short-term fixes, it is possible to use household items to raise and lower the pH value of your hydroponic system. Adding white vinegar or citric acid will help to lower the pH. At the same time, baking soda can assist in raising the pH. These items are best used within smaller systems as they are harder to monitor long-term.
Does aerating water raise pH in hydroponics?
Yes, aeration causes carbon dioxide to break out from its chemical composition. As a result, the overall pH level can be affected. When the carbon dioxide leaves and the oxygen levels rise, so too do the pH levels of the nutrient solution.
How often should I adjust the pH hydroponics?
There isn’t a universal timeframe for adjusting the pH level of a hydroponics system. Many factors can throw it out without warning. In the beginning, it’s best to check the pH levels daily until you get a bit of a feel for how your system operates.
Then it’s just a matter of ensuring that your routine checks are made when you think the plants aren’t doing what they should be. Measure the amount of water and add nutrients accordingly.
Conclusion
Using hydroponics as a method to grow can be seen as a tedious balancing act, and for a good reason. It takes only the smallest changes in the nutrient solutions environment to throw the whole system out of whack.
Thankfully, as long as you make routine pH checks and adjust accordingly, the task becomes easier each time. We hope that this article has given you the confidence that you need to make the adjustments required for your system.
Above all else, make sure you do what works for you. Thanks for tuning in, and as always, happy growing!
