Unsure how far to insert a moisture meter into a pot? This video shows you.
#healthyhouseplants #moisturemeter #indoorplantcare #houseplanttips #plantwatering
Welcome to HealthyHouseplants.com, where we teach you all about gardening in The Great Indoors! If you’d like to support our show, please use our Amazon affiliate link below.
In this video, we’re answering a viewer question from William Lane about how to properly use a moisture meter. Specifically: “How do I know when to water if part of the soil is dry and part is wet?”
Many people are confused by the difference between using the finger test—sticking a finger an inch into the soil—and using a moisture meter, which can reach 12 inches or more. It might be dry near the surface but still moist deep down. So, when should you water?
I’ve covered moisture meters in other videos, but today we’re going to go in-depth—literally—on how far to insert the probe and what part of the soil to base your watering decision on.
💧 How Deep Should You Insert the Moisture Meter?
When using a moisture meter, don’t just test the top inch. For accurate watering, insert the probe about one-third of the way down into the soil. This zone reflects the critical root area for most houseplants. If this area is dry, it’s time to water—even if deeper layers are still moist.
Also, finger testing isn’t ideal, especially for larger pots—it’s messy, awkward, and doesn’t give a deep enough reading. Moisture meters are inexpensive, fragile if dropped, but very useful for accurate watering in both small and large containers.
🪴 Demonstration Using a Dracaena Plant
We demonstrated with a four-foot Dracaena in a large pot. The top inch showed red (dry), and deeper readings confirmed it. This plant needs water.
For another Dracaena in a smaller pot, we inserted the probe one-third of the way down and tested several points. Most readings were around 4 or 5, indicating some moisture still present, so we’ll wait a few days before watering again.
Always test multiple spots around the soil—3 to 5 depending on pot size—for a good average.
🔁 General Moisture Guidelines
Most houseplants: Water when the reading is at 4
Succulents/Cacti: Water at 1 or 2
Moisture-loving plants (e.g., Maidenhair fern): Water at 5 or 6
Always apply these guidelines to the top third of the soil, where most root activity occurs.
Moisture Meter Watering Tips for Houseplants
How far down should I insert the moisture meter?
You should insert the moisture meter about one-third of the way down into the pot. This level reflects where most houseplant roots are concentrated.
Should I water if the top soil is dry but deeper soil is wet?
No. Focus on the top one-third of the soil. If this zone is dry, it’s time to water, even if deeper layers are still moist.
Is the finger test reliable for checking soil moisture?
The finger test is only somewhat reliable for small pots. It’s not ideal for larger containers. A moisture meter gives a much more accurate reading.
How many areas in the pot should I test?
You should test 3 to 5 areas around the plant to get a representative sample of the soil’s moisture content.
When should I water based on the moisture meter reading?
For most houseplants, water when the moisture meter reads 4 in the top third of the soil. Succulents need watering at 1–2, and ferns at 5–6.
Patreon: 
/ healthyhouseplants
One-time donation: https://ko-fi.com/healthyhouseplants
Sign up for my monthly newsletter: http://eepurl.com/g1PCSH
As an Amazon Associate I earn from qualifying purchases. I may earn commissions for purchases made through the links below.
Moisture meter: https://amzn.to/3TEUu5N
Moisture meter (extra long): https://amzn.to/3NZZnEh