Soil Moisture Meter – How to Use, Care and Store Your Moisture Meters

Soil moisture meters are the perfect gardening tool to help you understand your plant’s water needs. Water absorption rates can vary depending on the plant, ambient environment, and time of the year. Use a soil moisture meter to time your watering schedule correctly.

How to Use Soil Moisture Meter

One of the biggest challenges for first-time plant parents is understanding their new plant baby’s water needs.

If we had to pick the most common cause of plantacide (we just made up a word for plant fatalities😉), it would be water stress.

More often than not, it is a case of too much love. And although the new plant parents have the best intentions, they innocently stick to a regimented watering schedule (usually once a week), leading to the plant being overwatered and distressed.

Fortunately, there is a tool that can help all indoor plant enthusiasts (new and experienced) overcome this problem. And it is called a soil moisture meter.

The good news is it is a budget-friendly instrument that can easily be found in online marketplaces (like Amazon) or at your local nursery.

Check out our video detailing the unboxing of our favorite affordable soil moisture meter from Kensizer. We also run through a visual demonstration of how to use the soil meter and the results after a bottom watering session.

How to Use a Soil Moisture Meter for Houseplants

For those of you who prefer to follow written instructions, below is a step-by-step guide on how to use a soil moisture meter.

1. Always clean your equipment

Before you use any equipment shared between pot plants or sources of soil, we always recommend cleaning it before use.

To reduce any chance of cross-contamination, use rubbing alcohol (isopropyl alcohol) to clean any part of the soil moisture meter that comes into contact with soil (the probe).

The rubbing alcohol will kill any disease or bacteria.

Clean the Probe

2. Prepare your plant

This is an excellent opportunity to give your houseplant a quick tidy.

Remove any dead foliage or debris from the top of the soil and trim off any damaged or dying leaves.

This will help give you a clear view of where to insert the soil moisture meter.

3. Test multiple locations in the potted plant

To get an accurate reading of your pot plant’s moisture levels, we recommend testing different soil areas around the container.

You can see from our video we tested five different areas around our Monstera, which all measured between 2-3 on the soil moisture meter. This confirmed that our Monstera was thirsty and needed a top-up.

Taking an average reading will help prevent misdiagnosing the water levels, resulting in you causing your plant suffering from water stress.

Test Soil in Multiple Locations

How to read a soil moisture meter

To test the moisture level in any particular area of your potted plants, insert the probe 2/3 of the way down into the soil.

Make sure to leave the meter in the soil for 2-3 seconds while it settles on a reading.

How to Interpret and Apply the Results

As we mentioned, take an average of the readings from the soil moisture sensor around the container.

You can safely ignore the outlier if you encounter any significant discrepancies (like a very moist area when the rest of the readings are measured dry).

The Kensizer soil moisture meter model conveniently differentiates three zones:

  • 1 to 3 – Red Zone – Dry Soil
  • 4 to 7 – Green Zone – Moist Soil
  • 8 to 10 – Blue Zone – Wet Soil

The trick to watering your indoor plants is knowing each plant’s moisture level preference.

Each type of plant has different water requirements – which we’ll elaborate on in the next section.

4. Time to Water Your Plants (only if required)

If there is only one thing you take away from this article, it should be this…

Each type of plant will need to be topped up with water at different readings on the moisture meter.

This may not make sense to you, but let us explain.

In our video for the Kensizer soil moisture meter, we tested the levels of moisture for two different plants. Our Monstera and Sansevieria Trifasciata Zeylanica. We did this on purpose to demonstrate an important point.

The Monstera showed an average reading of 2-3 on the moisture meter. This was just as the indicator moved from the MOIST zone to the DRY zone. The perfect time for a water top-up since Monstera’s like moist soil to grow.

If, however, our Sansevieria showed a moisture meter reading of 2-3, we would have opted NOT to water it and re-test the moisture levels in a few days. This is because Sansevieria Zeylanica prefers its soil to dry completely before requiring another drink (which, coincidently, the soil moisture meter indicated with a reading of 1)

5. Re-test your plant’s soil

Once you have watered your indoor plants, allow any excess water to exit from the drainage holes and re-test each plant with the soil moisture meter.

Retesting with soil moisture meter after watering

Remember to clean the moisture meter probe each time you test each plant.

6. Clean and store soil moisture meter

Once you have finished testing and watering your pot plants, clean and store your soil moisture meter properly.

Use your rubbing alcohol to wipe the probe clean, and wrap the probe in a dry kitchen paper towel to protect it while not in use.

Try not to store the probe in direct sunlight or places that get extremely hot, like above 95° Fahrenheit (35° celsius).

Why Use a Soil Moisture Meter?

When we first discovered the soil moisture meter, we literally said out loud, ‘Where have you been all our lives?’

If we had known about moisture meters when we first entered the gardening space, it would have saved many a dead houseplant and shortcutted our learning phase immensely.

Which is the main reason why when one of our community members comes to us with a dying or problematic pot plant, we tell them to buy a soil moisture meter.

Here are the reasons why.

Benefits of Soil Moisture Meter

Soil moisture meters:

  • Take the guesswork out of watering your plant. This helps to reduce the chances that your potted plants experience water stress, contract diseases like root rot, and much more.
  • Help you become a better plant parent and gardener. It is true when they say with knowledge comes power. As you consistently measure your plants’ moisture levels, you will become familiar with their water absorption rates, giving you an intimate understanding of how they behave and their needs.
  • Help to reduce water wastage. Over-watering indoor plants is a common problem. Therefore, having a soil moisture meter on hand to measure the soil will prevent too much water from being wasted on your plants.

How does a Soil Moisture Meter Work?

Soil moisture meters use the metallic probe (copper in the case of the Kensizer) to measure the conductivity of the soil.

The water present in the soil facilitates the conductive properties of the soil. Meaning the more moisture present, the more conductive the soil.

Vice versa, a lack of conductive nature in the soil means little to no water content available to carry the electrical charge.

How Not to Use a Soil Moisture Meter

There are a few things to avoid doing while using your soil moisture meter.

Do Not Use Excessive Force to Push it Into the soil

If you struggle to insert the meter probe into the soil, resist the temptation to force or hammer it into place.

You will likely bend or break the probe and damage your plant in the process.

If the soil is too hard for a probe to penetrate, it will be too dry and have solidified. It will be devoid of moisture and need more extreme watering techniques, such as a water bath.

Alternatively, a plant root or rhizome may be in the probe’s path, and forcing it in may damage your plant, opening it up to disease and infection.

Never Submerge the Probe into Liquid

As tempting as it may be to test that your soil moisture meter is working by dunking it into a cup of water, it is simply not designed to be used in this way.

In fact, doing so will cause it to malfunction and break.

Just stick to testing moisture levels in the soil, okay?

credit: giphy

Do Not Leave it in Your Pot Plant

The last soil moisture meter No-No is not to leave the probe sitting in the soil (aside from the times you are testing).

We know. We were disappointed to learn this was not the intended use of a soil moisture meter as well.

The problem with leaving a moisture meter in the soil is that it loses its calibration as it is constantly exposed to moisture. This means it won’t provide accurate moisture readings and will become useless.