If you don’t know what “moist, but not soggy” exactly means and how to estimate moisture of the potting medium, this article is for you.

As to watering plants, we can take three approaches.

First, we can bet on a manual gearbox and practice with using a finger to check the moisture of the soil. Don’t laugh, I guarantee that, when practiced, this is the most reliable method to use. Becoming a master takes time and effort, like in every art ;).

Secondly we can turn our jungle into the automatised hydroponic kingdom and not be bothered with moist, as it will be almost always in an optimal position. The kind indicators will tell us wether it is time to water our plants.

Thirdly, we can use moist meters to either back up our “finger assessments” or alone. In both cases we need something that, at least partially, works. I will tell you about three devices that I’ve used recently.

I’ve tested two moisture meters so far, and I have some doubts in this subject. I mostly use a very airy mix for my plants, so I think that the problems with those moisture meters are mostly due to this fact. The contact area with the meter is very small and it is not enough for them to measure it the moisture level properly.

Let’s check the hip, and pretty simple device The Tessa Water Meter. It shows you whether your plant has had enough water by changing the colour from white to blue. Pretty neat! The meter is available for medium and large plants and should last about 6-9 months. The manual is also very simple. Just insert the Tessa Water Meter vertically into the soil. The colour of the meter will turn blue when the plant has had enough water. When the colour turns white again, your plant is thirsty. It is not a device that you can just move around from pot to pot in my opinion, so it is not very efficient.

I’ve tested this moisture meter for 6 months now and since it was 3 months it lost its ability to go totally white, but it doesn’t seem to be a big problem. When the soil is dry, it goes pale blue, even when my Philodendron is falling out of the pot, but well. I’ve learned to recognise the shade of the blue that indicates, that it is time to water. When the soil is moist, it gets darker. So, I won’t say that this option is bad, but it is not perfect. It is very pricy, especially if you would like to have it on all of your plants, and you have 200+ of them.

COST: around 8 euro

Soil moisture meters are small hygrometers that let you measure average moisture levels. You can insert them into the soil to determine how moist it is. They measure moisture by detecting electrical currents in the soil. Most of them have a little window display that shows the moisture level on a scale. Also, for most of the time you don’t need any battery for it to work. It provides a consistent analysis of how much water is in your growing medium (if you leave it there). These tools typically give you a reading within 60 seconds. It is very portable and you can measure the moist in all of your plants. It takes time though ;).

In theory…

I had like four of those, and don’t get me wrong, maybe I can’t use them properly, but I’m pretty sure that it should be easy. Anyway, if you don’t use universal soil for your plants, forget about it. The contact surface with the electrode is not sufficient enough to measure the moisture of your potting mix properly.

COST: around 10 euro

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I got this at the beginning of autumn in Europe in 2021 from Ali Express. The idea is again – simple. Here the contact area with the medium is larger because the electrode is flat and wide. The meter has an electrode and it is connected to the electronically reader which gives a feedback in the form of colours.

Green: your plant is watered

Red: your plant is dry

Blue: man, you overdone it

It should stay in one place in order for you to know, wether it is time to water again, but the instruction says that you can also change the pots, to check the moisture level in another plant. The cleaned electrode needs time (5-10mins) to take a good reading. I keep it in one place and didn’t move it since November.

I have two of those and one is sitting in my huge Philodendron. It’s pot doesn’t have drainage holes, so it was crucial, to check moisture there.

So far I’m very happy with these. After four months the battery still works and the readings agree with the finger method. I feel safe using them even though the meter has a short electrode (so it doesn’t penetrate deep into the soil).

COST: around 2 euro

Tell me what do you use in the comments! What are your thoughts on moisture meters? Are they necessary?

*NOTE: This post is not sponsored and the links are not affiliated.