The Important Facts to Using a pH Meter
Do you love to garden? Do you need to test your soil from time to time but you’re not sure how to do that? Do you not use soil and use the hydroponic method? Do you have the right equipment to test the acidity or basicity of your soil or water?
Awesome! You are in the right spot.
In the following read, you will learn the basics of what a ph meter is and why it is so important to gardeners. You will learn the following things: how to use a ph meter for soil, how to use a pH meter for Hydroponics and how to calibrate ph meter. The pH meter is important for a number of reasons, the biggest being that the result can indicate if soil, for example, is very acidic or alkaline or neutral. Farmers tend to rely on data from a pH meter because it will determine the available amount of essential nutrients. For example, most horticultural crops will grow in soil that is between 6 and 7.5. The pH meter is based from 0 to 14. 0 indicates most acidic and 14 is most alkaline. Farmers want their crops to grow in soil that falls in the middle of the scale. That adds nutritional value for when they go and sell their crops. Some crops do require a more acidic soil like rhododendrons, blueberries and azaleas. There are ways to make the soil more acidic just as well as make it more alkaline. Experts need tools like a pH meter to be successful in growing crops that are edible, viable and delicious.
The reason why it’s important for you to monitor the pH levels of soil is because soil pH influences soil-dwelling organisms. The organisms’ well being does directly impact soil conditions and plant health. On the other hand, too low of a pH level can indicate plant poisoning meaning the plant’s nutrient value would be rendered toxic. Additionally, sometimes aluminum can be released if the pH level is too low which is not considered a plant nutrient which could stunt the growth or nutrient uptake.
When it comes to a hydroponic system, pH levels are important to monitor because of the availability of nutrients for your growing plants. Hydroponically grown plants do not benefit from the microorganisms and organic matter in soil. Because there is no soil, gardeners need to closely monitor pH levels because if there is not a balance, plants can be deficient in iron and calcium and the plant growth could be stunted.
What you will need in order to properly use pH meter
In order to get started with measuring the levels of your soil or hydroponic system, you will need to also consider the following things:
- Materials necessary to adjust pH levels
- Places to store your pH meter
- Buffer solution used with pH meter calibration
Buffer solutions are important to be used when calibrating pH meters because they help resist changes in pH levels. Benefits of the buffer solution include:
They stabilize the pH level for long periods of time
They help resist changes in the pH level if you accidentally add substances that could significantly change levels
Buffer solutions also are easily available and prepared for any given pH
For the hydroponic system, gardeners can make their own buffer solution which is more cost effective long term. For example, if you need a pH level of 7 buffer here are the steps to create your homemade batch:
- Fill a container with tap water and fill it 80% of the way
- Add 10g of mono potassium phosphate
- Stir solution until it dissolves
- Add KOH very slowly and measure your pH until you reach 7.00. If for some reason you add too much and go above 7.00, add more mono potassium to lower the pH level.
- Let the buffer sit for a few hours and then test your solution again
- Make sure you store the prepared buffers in air-tight bottles and store a dark closet/corner
Storing your pH meter is important because you want to always get an accurate read. Here is a quick list of steps to properly store your pH meter to allow for maximum use.
- Store the pH meter in a cool, dry and clean place
- Keep out of direct sunlight
- Make sure the device is dry – there can be water damage is left in water for long periods of time
- If you aren’t going to use the meter for a long period of time, make sure you remove the batteries
- Remove all pH probes if storing the pH meter without use for longer than two to three weeks. You want to make sure you check your meter regularly because the pH probe tip must not dry out. When storing the pH probe, the tip needs to stay moist
Whichever pH meter you decide to buy, I recommend following the instructions included with the device. The instructions should give good insight on how to clean, store, use and calibrate the pH meter as well as outline any error messages and provide technical specifications.
There are going to be times where you may have to either lower or raise the pH level of your soil or hydroponic system. To do this you can apply ground limestone to help raise the pH level or use fertilizer like urea, ammonium sulfate or ammonium nitrate.
Everything you need to know on how to use your pH meter
The accuracy of a pH meter is important as it will give you a level reading either for your soil or hydroponic system. The most popular method to measure the pH level of your soil is using the digital pH meter. Here are the steps to using the digital device:
- Take a scoop of soil from your garden or pot and place in an open container
- Make sure the soil doesn’t have any pebbles, sand, leaves, rocks or other debris
- Also the best sample to use is a scoop of soil closest to the root.
- Add water and the amount of water should match the amount of soil
- Sir the soil and water for 5 to 10 seconds and then let sit for 15 mins
- After 15 minutes have passed, stir the soil for another 5 seconds
- Place the meter stick in the soil and wait for the screen to show you the pH level
- Clean right afterwards as to not contaminate or disturb another reading
Unlike soil, the hydroponic method is a bit different when it comes to checking the pH level of your nutrient solution. There are three different methods, but like soil, the digital method is the easiest and most accurate. It is also the most popular.
Digital meters can come in all sizes and price ranges so I recommend doing your homework to find a meter that is within your price range. There should be a digital pH pen that is included with most digital meters and that is the most commonly used tool for a gardener when it comes to this step. For the hydroponic system, simply insert the electrode tip of the meter into the nutrient solution. And then wait for the digital pH reading to pop up on the screen.
Part of maintaining the integrity of your pH meter, you need to make sure you calibrate and standardize your pH meter.
Why is calibrating your pH meter important?
It’s vital to make sure the proper amount of electrodes are released depending on any changes that may have occurred since the last reading. The calibration ensures that the meter is releasing the proper level of electrodes each time to give an accurate and repeatable reading. It is recommended that the calibrating stage is done on a daily basis. If that is not possible, it’s also okay to calibrate one or twice a week.
Essentially, calibrating a pH meter allows for you to measure the value you receive in any known solution. In this case, that is usually the pH buffer and you then control the difference. If you end up adjusting the pH electrode, then you ultimately correct the current measurement value to a reference value which is normally the one printed on the buffer bottle.
The adjustment is known as the calibration. Make sure you do the following before starting the calibration process:
- Program the transmitter for the buffer solution
- Get the following supplies
- Distilled water
- Paper towels
- Clean beakers
- Cleaning solution
- Buffer solution – get two solutions
Once you have the materials listed above, follow the steps below to accurately and appropriately calibrate your pH meter.
- Examine the pH electrode – make sure it’s not damaged. If it’s dirty you can use the cleaning solution according to the instructions. You want to make sure there is no cross contamination between pH readings
- Flush the pH sensor – use the distilled water to flush the sensor
- Dab and pat dry the sensor – you can use the paper towels for this step.
- Make sure you don’t rub the sensor because that can significantly compromise the charge
- Submerge the pH electrode – use one of the beakers and fill it with one of your buffer solutions. Then slowly lower the electrode into the solution
- Calibrate the pH meter – this is where you can start to calibrate and adjust. Look at the stability value. Once the value stabilizes you can accept and set this value point
- Rinse the pH sensor with the distilled water and then repeat the same process with the other buffer solution
There are going to be times you run out of a calibration solution.
What do you do then?
This is where you may need to get a bit creative. The most important thing is having a calibrated probe on hand. The next step is making sure you have the following materials:
- KOH which is monopotassium – you want a pH around 7
- Citric acid – you want a pH around 4
If you go back earlier in this article you will find the instructions of how to create your own buffer solution. If you don’t have these options then my recommendation is you wait to calibrate your pH meter. This may seem inconvenient but there could be long term damage to your pH electrode if you try other household products.
Like mentioned earlier, there are two other methods that you can use for checking the pH levels if you are using the hydroponic system. If for some reason you don’t have the buffer solution to calibrate your electrode, you could try another method of testing the pH levels. This could be a way to hold you over until you can get to the store to acquire more solution.
The first alternative to using a digital meter is using paper test strips. The strips are covered in a pH sensitive dye that will change colors when dipped into the nutrient solution. It’s important to have your color chart handy because you can then do a cross comparison. You can try and accurately pick where your strip falls on the chart. This method is the cheapest and not as good as the digital method but it can get results. Sometimes the type of nutrient you are testing will also determine the accuracy of this type of test.
The second alternative is using a liquid based pH test kit. This method has proven to be more accurate than the test strips. Conducting this method is also fairly easy, all you need to do is add a few drops of pH sensitive dye into a small vial that contains your nutrient solution. Watch carefully as your solution will change colors and you can do another cross comparison to your pH chart.
Both methods are great alternatives if you are not able to calibrate your pH meter for a new read or if you are needing to buy a new digital meter.
That’s a wrap!
Just like the method of growing microgreens hydroponically or in soil, the method of maintenance and upkeep is just as important. Testing your pH levels to cleaning, storing and maintaining your pH meter is vital to ensuring you get the best results.
The digital method of testing is the most popular and the most accurate. There are going to be times when you are receiving an error message on the device screen and you are not able to properly use the probe.
What do you do then?
First of all, it’s important you keep the instructions and manual to the digital device. This can be handy using in tandem with this article. There are some technical things you can do to troubleshoot the issue. An error message may pop when trying to turn on your digital device. This typically will happen when you have failed pH calibration.
This feature is great because if the error indicator disappears that means your device is calibrated correctly and ready for its next pH test. But if for some reason you are still getting an error message on the device you will need to recalibrate. Here are some reasons that may cause the error message to populate:
- The wrong solutions were used
- The pH probe was contaminated
- The calibration solutions were contaminated
- The pH probe was not properly attached
- The pH probe was either worn out or damaged
Remember that it’s important to calibrate to pH 7.00 first and then calibrate to pH 4.00.
In addition to the error messages after calibration, here are some other inaccuracies you may encounter with viable solutions:
pH reading does not change from solution to solution
REASON: broken glass bulb, tube or connector
SOLUTION: Check the soil pH probe for any damage and if necessary replace the probe
Displays low battery indicator
REASON: Insufficient power to take a reliable reading
SOLUTION: Replace the batteries. I do not recommend using rechargeable batteries
“Or” “Ur” whale in pH mode
REASON: over range pH or under range pH
SOLUTION: Solution greater than 14.0 pH or solution less than 0.0 pH. Check the pH probe connection. pH probe could be faulty or the pH meter could be wet inside
REASON: Batteries are dead or inserted incorrectly
SOLUTION: Check batteries and if you need to replace the batteries
pH reading inaccurate
REASON: soil pH probe damaged or old
SOLUTION: replace soil pH probe
REASON: pH calibration unreliable
SOLUTION: Calibrate soil pH probe
REASON: incorrect pH calibration
SOLUTION: make sure the calibration solutions are accurate. If you are not sure, replace when in doubt. Wait long for readings to stabilize before calibrating to a constant and consistent value
There are a lot of things to account for when it comes to measuring the pH of your soil or hydroponic system; however, I can promise you that it’s all worth it in the end. If done correctly, you will have a strong and healthy looking crop that is not only full of nutrients but also full of color and vibrancy. This step is not worth cutting corners or finding quick and easy solutions because it serves as a critical step in the horticultural process.
Wouldn’t you want to do it the right way the first time so you are not spending precious time and resources fixing what could have been correctly in the first place?
Yes and yes this step may take time but invest in it because it will guarantee long term success and growth of your crops, greens etc.