Ask any gardener, hydroponics or otherwise, what is the thing that they need to constantly monitor to ensure the health of their crops? They will all say that it’s important to watch the pH level of their planting medium.
So Why is pH Important?
Suppose the pH level of the water in your hydroponics setup is leaning towards being more alkaline or acidic. In that case, the plants will not efficiently absorb the nutrients that they need for steady growth and development.
The optimum pH level will vary depending on the plant, but most plants thrive at slightly acidic conditions, with pH levels between 5.0 and 7.5. However, if the pH levels go beyond 6.5, nutrients and micronutrients start to separate from the solution and stick to the reservoir walls.
For your plants to absorb the nutrients you’re adding; they must be suspended in the solution. If the nutrients precipitate out the solution, the plants’ roots will not be able to absorb them and they might suffer from nutrient deficiencies in the future if this problem is not addressed immediately.
What Causes High pH in Hydroponics?
When the pH level of your hydroponics system gets too high, it can result in poor plant development and low fruit and flower yield. The higher the level, the worse it becomes for your plants.
What causes the water to have an increased pH level? The usual suspect for unnaturally high pH levels in hydroponic setups is hard water, the growing media or the container you are using as tanks might have something to do with it. Limestone (which is present in hard water) and concrete can leach carbonate into your water and raise the pH levels.
Having high pH levels is also normal for new systems. Until the bacteria colony in the water has established itself and the nitrification process is working properly, carbonate build-up in the water will rise because there are not enough bacteria to consume it all.
Using Lemon Juice to Lower pH Level
If you are looking for a cheap and natural way to lower the pH levels of the water in your reservoir, you can use either lemon juice or lime juice.
How does this work? Lemon juice helps lower the pH levels by raising the number of hydronium ions and decreasing hydroxide ions. Since pH level is the measurement of hydronium ions in the water, it is safe to say that the more hydronium, the higher the pH level. Lemon juice increases the number of hydronium ions because it adds a hydrogen atom into the solution.
How much lemon or lime juice will you need to lower the pH of the water in your tanks? To make the pH level of 100 ml of water lower down to around 5.5, you will only need a drop of lemon or lime juice. Experts also estimate that to adjust the pH of a gallon of water, two drops of pure lemon juice can lower pH levels by 0.5. You can add more if needed.
Many hydroponic hobbyists have tried and tested using lemon or lime juice to lower the pH levels of the water in their reservoir. There haven’t been any reports of any adverse effects on the plants unless the user used too much stuff.
Can you use citric acid instead of lemon or lime juice in your pH-down solution? Of course, it is even better if you do since you can easily measure the amounts exactly and not depend on just the number of drops.
Nick is the author of ‘Hydroponics for Beginners‘ and ‘How to Grow Microgreens‘.
Nick writes content on his website about hydroponics and microgreens. So you can enjoy growing plants yourself!