Do Moisture Meters Damage Plant Roots?

For many gardeners, watering is tricky to get right every time. If you constantly under or overwater your plants and can’t seem to resolve the issue, you may enlist the help of a moisture meter. These devices are buried in the soil and indicate how much moisture remains in the soil, helping you understand the perfect time to water.

Moisture meters won’t damage plant roots if you keep them at a safe distance from the plant and use them correctly. Removing the moisture meter at the right time and drying it also prevents rust which can damage roots.

This article will discuss how to safely use a moisture meter, the symptoms of damaged plant roots, and how to fix any accidental root damage from incorrect use.

Preventing Root Damage: Best Practices for Utilizing Moisture Meters

Soil moisture meters are simple devices used to measure the soil’s moisture content. For home gardeners, a hand-held moisture meter is enough for general gardening needs.

Regardless of the type of moisture meter you have, it can be easy to misuse it, potentially resulting in root damage. It needs to be placed in the soil carefully and used correctly to protect the sensitive root system from accidental breakage. While minor root damage probably won’t kill your plant (they are tougher than you think), it’s best avoided to prevent stunted growth or potential problems with disease.

Let’s go through the steps of using a moisture meter correctly to help you avoid root damage in future:

1. Understand Your Plant’s Root System

One of the most important things to consider when using hand-held moisture meters is the type of roots your plant has. Depending on this detail, you will need to adjust how you use the device.

Hand-held moisture meters typically have one or more metal probes that send signals to a mechanism in the device that determines the level or amount of moisture in the soil. When used carelessly, these probes can puncture the roots, potentially causing damage.

There are different types of roots you will have to consider, such as taproots or fibrous roots, that impact how the roots spread beneath the soil. Some plants have shallow root systems while others travel deeper into the soil. When growing in containers, the last time you repotted also has an impact as the roots may be overgrown, filling the entire container and making them harder to miss.

Fleshy underground structures like taproots, bulbs, and tubers are especially at risk from puncture wounds from metal probes. 

Understanding your plant’s root system can help you estimate how far and how deep into the soil you should insert the probes to get an accurate reading without damaging the roots.

2. Gently Insert the Probe Into the Soil

The pins or probes of hand-held moisture meters are designed to make them easier to insert into the ground. That is why you don’t need to use much force to bury them to an ideal depth. Patience is key if you want to prevent damage.

If you have plants with fleshy roots like carrots or onions, gently insert the probe into the soil, and stop when you feel some resistance. Chances are, you are about to puncture the root. Pull out the probe and re-insert half an inch (1.25 cm) away from the initial spot.

3. Let the Probe Rest in the Soil for up to 60 Seconds

Metal probes can build up rust when exposed to moisture for too long. Although it won’t result in rusting immediately, making a habit of it can present problems in the long run. This impacts the effectiveness of your meter over time.

It typically takes 30-60 seconds to get an accurate reading on moisture meters. After this time, you can pull out the probe and clean it. This simple practice can help you protect your plant’s roots and lengthen your moisture meter’s lifespan.

4. Never Leave the Probe in the Soil After Use

Never leave your moisture meter on the ground, whether in the soil or on it. The metal components may corrode when you leave soil debris and moisture on their surface. In addition, the sun’s heat may also speed up the corrosion rate.

After use, clean the metal probe with a moist cloth to remove visible debris. Then, wipe it with a dry, lint-free cloth. Store the device in a cool, dry place, free from the elements to prevent damage.

5. For Stationary Moisture Sensors, Follow the Product Label

Some moisture sensors are stationary, so you can bury them in the soil for extended periods. This type of moisture meter is typically used in bigger fields.

When using stationary moisture sensors, always read and follow the instructions laid out by the manufacturers. The instructions usually indicate ways to manage the device for optimal use while preventing potential damage to crops.

Symptoms of Damaged Roots

Severe damage to the plant roots due to improper use of moisture meters is rare. Nonetheless, if your plants’ roots suffer from some degree of damage, they will show signs that can help you address the issue.

Here are some symptoms your plant has damaged roots:


Depending on the extent of the damage, plants with broken roots may exhibit leaf or flower wilting. For plants with partially injured roots, wilting occurs on the side of the affected roots. So if you notice your plant’s leaves or flowers drooping and drying up a few days after using your moisture meter, you may want to check if the roots are damaged.

Fewer Leaves on Affected Side

Another sign that your plant has root damage is when there is noticeably less foliage on the side where you often use your moisture meter.

Short, Distorted Leaves

When punctured, the cavities in bulbous roots (such as onions and garlic) become a target for secondary infection from bacteria or fungi, resulting in short, distorted leaves. Eventually, it can cause your plant to die.

How to Fix Plant Roots Damaged by Moisture Meters

How you should manage and/or fix root damage caused by moisture meters depends on the severity of the injury.

Here are some tips to keep in mind:

Remove Damaged Bulbs or Tubes

When secondary bacterial or fungal infection occurs from puncture wounds on fleshy roots, there is a risk nearby plants will be infected. It is best to remove and properly dispose of affected plants.

Prune Wilted Leaves, Flowers, or Branches

Plants with minor root injury from probes may show symptoms but can recover naturally. Pruning affected parts will help the plant focus on healing and regrowing healthy roots.


As the saying goes, prevention is always better than cure. Moisture meters are helpful gardening gadgets to prevent over-watering or under-watering your precious plants.

However, like with any other gadget, careless use of moisture meters may cause damage to your plants’ roots. Luckily, such issues are easy to avoid. Basic knowledge of your plants’ root structures and careful use of the meter probe are often enough to keep your plants safe.

Written by Alexander Picot, Reviewed by Madison Moulton

Alexander Picot

Alexander Picot is the founder of and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.

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