Plants need water to survive, but how much is enough?
Most people know it’s hard to determine when plants need water by feeling the soil.
That’s why the best gardeners use a soil moisture meter to test when a plant’s too dry or wet for healthy growth.
By reading this guide, you’ll quickly learn which top five soil moisture meters make my review list, why you need a moisture meter, and what to watch out for before purchase.
If you’re unsure which model to pick, I highly recommend the REOTEMP Garden and Compost Moisture Meter for the versatile length of the probe, easy-to-read display, and high accuracy.
If you grow mainly houseplants or want to go gentle on the budget, I suggest you select the Luster Leaf 1830 Rapitest Soil Moisture Meter with the hand-held display and corded probe that can test even hard-to-reach plants with ease.
I also answer frequently asked questions before giving you my top recommendation, so you too can benefit from this phenomenal gardening tool!
Top 5 Best Soil Moisture Meters
1. XLUX T10 Soil Moisture Sensor Meter
The XLUX T10 Soil Moisture Sensor Meter is a low-cost way to ensure all your plants, from the garden to your indoor pots, maintain proper moisture levels so they remain healthy.
The single seven-inch probe slips easily into most potting and garden soil and causes less damage to delicate root systems. The length of the probe is ideal for reading deep into the soil where the roots grow, which eliminates having to dig holes to check soil conditions manually.
I like the battery-free operation of the meter, so you don’t ever have to worry about replacements or corrosion issues. The large window makes it easier to read the moisture scale, and the straightforward color-coded levels show your plant’s exact watering needs.
Things we like:
- Battery-free means no added expense
- Large window and color-coded scale make it easy to read
- Indoors and outdoors use eliminates the need for two separate meters
- Single probe is less damaging to roots
Things we don’t like:
- Use in overly dry or rocky soil can damage probe
- Some meters show faulty “dry” readings even after watering
The XLUX T10 soil moisture meter makes the list due to the simple operation and reasonable price. This meter is best for the average gardener who is unsure whether or not it’s time to water their plants.
2. Atree Soil pH Meter 3-in-1 Soil Tester
The Atree Soil Tester Kit is a dual-probe unit that works inside and out to better monitor the needs of your plants.
At just under seven inches long, the probes can reach past the surface soil to accurately read the amount of moisture at root depth. Change the setting to reveal soil pH and light conditions so you can improve your plant’s overall health.
I like the dual-probes that give off reliable readings, the battery-free operation, and the quality materials that should last for many gardening seasons. The window display is large and accurately displays all three readings after ten minutes with a push of a switch.
Things we like:
- Long, dual probes provide more accurate readings
- Light, pH, and moisture readings help increase plant health
- Battery-free and durable construction saves money
- Single unit works for both indoor and outdoor plants
Things we don’t like:
- Use in rocky or hard soils could damage probes
- Will only read natural sunlight, not incandescent or LED grow lights
- Probes can bend if not careful
- Need to wait ten minutes for a reading
I consider the affordable Atree 3-in-1 Soil Tester a top contender on this list because the extra features help dedicated gardeners see when to adjust their plantings water, light exposure, and pH levels for optimal growth.
3. REOTEMP Garden and Compost Moisture Meter
The REOTEMP Garden and Compost Moisture Meter is a step up when it comes to accurate soil readings in all types of gardening situations.
The 15-inch probe is long enough to reach deep into the soil, especially when testing in a tilled garden or farm row. The no-nonsense design features a large, easy-to-read display that reduces eye strain.
The white case color stands out against dirt and foliage, so you don’t accidentally leave it behind.
I like how this unit displays readings instantly and offers a calibration feature so you can adjust the meter to the specific needs of various plants.
Things we like:
- Long probe is ideal for indoor plants and outdoor farms and gardens
- Calibration feature can pinpoint specific plant needs
- Heavy-duty construction for long-lasting operation
- Extremely accurate results eliminates guesswork
- Top-read display means you don’t have to bend down to see results
Things we don’t like:
- Needs a battery to operate
- Doesn’t read well in heavy clay or compacted soil
The REOTEMP moisture meter is one of my top selections for the rugged design that is easy to read and operate, even when you wish to change its calibration.
This model is best for gardeners who want the option of gathering moisture readings in deeper soil and also from within their compost pile.
4. Longruner LKP02-VC Indoor/Outdoor Soil Moisture Sensor Meter
The Longruner LKP02-VC Soil Moisture Sensor is an affordable option when you are looking for a quick way to check on your indoor and outdoor plants.
The probe is sturdy and long enough to accurately read moisture levels at the root level of most plants. The unit requires no batteries, which saves on the overall cost.
I like the large window display that tilts at an angle, so you don’t need to kneel to read the scale. The color codes are helpful to see at a glance if your plants need watering.
Things we like:
- Indoor and outdoor use increases convenience
- Durable construction of head and probe reduces chance of damage
- Accurate, easy-to-read display
- Requires no batteries
Things we don’t like:
- Need to take extra care to keep sensor on probe clean
- Must wait ten minutes for accurate reading
The Longruner has high customer-satisfaction ratings and is a top choice for homeowners looking for a budget-friendly way to keep from overwatering indoor and outdoor potted plants.
5. Luster Leaf 1830 Rapitest Soil Moisture Meter
The Luster Leaf 1830 Rapitest Soil Moisture Meter utilizes a handy cord and probe feature so you can see the results on the display more comfortably.
The sturdy construction and battery-free operation mean the unit will last and provide readings you can trust. The meter comes with a handy watering guide for over 150 plants, so you’ll know what moisture level is best for your specific species.
I like the probe being separate from the display. The cord allows you to place the four-inch probe into your houseplants while holding the display in your hand, which makes it much easier to test planters that hang or sit high on a shelf.
Things we like:
- No extra battery expense needed
- Separate corded probe means it’s easier to read the display
- Great for readings in hanging planters
- The slim design is easy to store when not in use
- Simple to follow instructions
Things we don’t like:
- Probe is short and meant mainly for a shallow houseplant or planter box readings
- Only meant to read in soil, not granular or rocky planting mediums
The Luster Leaf 1830 Rapitest soil moisture meter deserves to make the list because it offers a cord on the probe to conveniently read all types of potted or hanging plants.
This meter is best for homeowners with an abundance of houseplants who want a no-fuss, accurate moisture level reading.
Do You Really Need A Soil Moisture Meter?
Yes, having a soil moisture meter is a lifesaver to both you and your plants, because it’s hard to know what’s going on underneath the top few inches of soil.
Plant roots that receive too little or too much water will wither or rot, damaging the foliage or even killing the entire plant.
Here are the top reasons you need a soil moisture meter:
Overwatering plants is common since topsoil can quickly dry out, leading you to think the lower soil is also dry.
A good soil moisture meter reaches below the surface to deliver accurate readings at the root level, which helps you eliminate wasteful watering practices.
For extensive gardens or farms with water irrigation systems, a soil moisture meter reading can save even more water.
Soil moisture meters read the moisture content level either instantly or after several minutes. While checking the level does take time, it saves more time overall by stopping you from pulling out the hose or watering can and dousing plants that don’t need it.
When plants have the proper amount of water, you won’t have to spend time pruning dead leaves and stems or replacing entire specimens.
INCREASES YIELDS AND PLANT HEALTH
Water is an important ingredient when you want a healthy plant. For a plant to grow strong, the root system needs access to a consistent supply of water they can absorb from the surrounding soil.
When you can test the soil and provide your plants with the ideal amount of water, you’ll enjoy extra lush flowering plants, abundant vegetable crop yields, and healthier shrub or tree fruit production.
Things To Watch Out For
To ensure you are getting the best soil moisture sensor for your needs, always take a good look at these features:
The best sensor probes come in either copper or stainless steel.
Aluminum is another common metal used for probes, but it’s more prone to bending during use in firmer soils.
The display housing should be waterproof and be of metal or durable plastic material.
Any penetration of moisture inside the display head could cause corrosion of the battery or other internal parts, which will cause faulty readings or ruin the unit entirely.
Soil moisture meters need to be accurate to be effective.
Most inexpensive meters offer a “range” between wet and dry soil moisture, which allows for leeway in the moisture level reading and is precise enough for the average gardener looking to maintain healthy plants.
Higher-priced moisture meters can give exact percentage readings, which expert gardeners may find necessary to grow a wide range of plants successfully.
The depth of the probe affects accuracy as well, so the longer the probe is, the more room you have to move the sensor to the right location.
Multi-function meters may also test how much sunlight is reaching your plants or the pH level of the soil for sensitive plants such as blueberries. These separate indicators are an excellent addition if you have finicky indoor plants that need a set amount of light each day.
If you want a bit more control over moisture readings, consider investing in a unit you can calibrate to specific plant needs.
Even the best soil moisture meter will cause frustration if you have a hard time seeing the indicators, or you need to crouch down to read the front of the display.
Displays that show through the top of the unit or angle upwards are much easier to read than units that have the screen on the front.
A hand-held display with a separate probe and cord is the easiest to read since you can hold the display right up in front of your face.
Lastly, make sure the graphics are large and crisp, so you can spot the moisture level without needing to squint or lean in close. I prefer meters that include colors to further delineate between wet, moist, and dry conditions.
Most soil moisture sensors work without the use of a battery, which reduces the cost of using the unit over its lifespan. No battery also means you don’t have to worry about corrosion or draining of power during storage.
Sensors that use a battery will cost more to purchase and use over time, but they seem to offer higher accuracy and quicker results for the price.
Frequently Asked Questions
Why is soil moisture important?
Even the driest looking topsoil can retain plenty of moisture a few inches below the surface.
Many times a person unknowingly thinks poking a finger two inches down into dry soil means they need to water more.
Unfortunately, if the underlying soil is already moist, the excess water you add can cause root rot that could kill off your plants.
A moisture meter probe can reach down four to six inches into the soil, where most root systems spread out and where proper moisture levels are critical. Without a meter, you are only guessing at the level of moisture within the soil.
Do soil moisture meters work?
When you purchase and use a quality moisture meter following the manufacturer’s instructions, it should work as intended.
Keeping the unit and probes clean and dry between uses is crucial for accuracy and longevity.
In some instances, a moisture meter may display faulty readings, such as when soil conditions have high sodium content from fertilizer use.
Other times a person may “test” the unit by placing the probes directly into a glass of water, which is a big mistake that can permanently damage the sensors.
How does a soil moisture meter work?
Many commonly sold soil moisture testers without a battery consist of a single or double probe with a sensor at the tip. The unit itself is basically a battery with no conductor inside to create a charge.
The metal used for the tip will conduct current when it touches moisture in the soil. The more moisture on the sensors, the higher the current that generates, which makes the needle on the display move.
For large-scale growers, a soil moisture meter that utilizes a tensiometer or electrical resistance blocks that are more sensitive and provide more precise readings may be necessary.
Can you leave moisture meter in soil?
Never leave a moisture meter in the soil any longer than necessary to gather an accurate reading.
Leaving the meter in dirt degrades the tool making it useless. Debris can build up on the prongs, or corrosion from moisture can occur and affect the delicate sensor.
Letting the sensors remain in “active” charge mode if the soil is moist for extended periods will also cause damage.
After each reading, take a soft cloth to clean the probes and make sure they are dry before either testing the soil of another plant or storing the unit.
What level of moisture is acceptable?
Soil moisture generally ranges between 10-45 percent, with higher readings during and immediately after watering.
Most flowers, fruits, shrubs, and trees require soil moisture between 21-60 percent, and vegetables require between 41-80 percent.
The issue is that most soil moisture meters don’t display in percentages. They usually have a color-coded scale that reads from one to ten, with one being dry and ten being very wet.
Knowing the moisture needs of your particular plants is necessary when using a soil sensor.
Ferns may need to be toward the higher end of the scale since they require more water. Succulents need to be on the dry end of the scale, while most other plants do best when they read in mid-range.
For the majority of plants, expect to water again as the soil reaches around three on the scale. Let plants dry out slightly between waterings since continual wetness will rot out root systems.
I hope the information in this guide helps you understand how a soil moisture meter can be a beneficial gardening tool.
When you can’t seem to keep plants alive, the moisture levels within your soil is most likely the culprit.
Using a soil moisture meter is the answer to this dilemma and allows you to watch them thrive instead!