My Houseplants Kept Dying Until I Tried This $13 Device
Houseplants are notoriously difficult to keep healthy and alive, especially in winter. You’re trying to replicate a complex, naturally-adapted biome inside your home. Plants that thrive in the wild wilt on your counter and sometimes it’s very difficult to figure out what you’re doing wrong.
Humidity is one of the most common culprits. Not only do each plant’s needs vary, but if you notice a problem with a plant, the first (over)reaction is often to water, which can lead to overwatering, or withholding watering, which can lead to dehydration.
I’m certainly guilty of this habit cycle myself, so I figured why not buy a humidity sensor and see if I could set up a watering schedule based on real data: would my plants benefit? Could a cheap soil sensor help me save the orchid on my kitchen table that has been struggling for weeks?
How Soil Moisture Sensors Really Work
I’ve never heard of this brand, but the soil sensor worked perfectly for measuring dryness and humidity.
Common capacitive soil moisture sensors rely on the electrical properties of the materials from which they are made. Typically, they consist of two conductive surfaces separated by a non-conductive material, called a capacitor.
Dry soil acts as a dielectric, a substance that is not very conductive but can contain an electrical charge. This ability to store charge increases as humidity levels increase, which affects the electrical properties of the capacitor. The sensor measures the dielectric constant. It then translates it into a percentage, a number or, in the case of $13 sensor I bought on Amazona simple reading from a gauge with a range between 1 (dry) and 10 (wet).
The length of the sensor probe I purchased is a nice advantage, because it allows me to read the moisture level from the soil to the bottom of the pots, even very deep ones. This is crucial because roots can extract different amounts of water from the soil in a pot, and the soil can be saturated differently when watering at different depths.
Let data tell you when to water
Before this test, I relied on typical indicators to know when to water. I tried to follow a schedule with most of my houseplants, although I accumulated plants with different needs that needed to be watered at different frequencies. I also relied on anecdotal evidence, like the finger test, where I tried to feel the moisture in my plant’s soil, or by testing the weight of the pot or watching for signs of wilting or drought in the plant itself.
The problems associated with these methods are numerous. On the one hand, I have a garbage memory. Remembering to water on a specific day was hard enough; having to remember multiple schedules for multiple factories was untenable.
Contrary to popular belief, humans are not very good at detecting humidity.
The “anecdotal evidence” approach was not much better. Unless you stick your finger deep into the soil in different areas of the pot, you won’t get an overall sense of moisture, and surface moisture can be misleading. Additionally, and this is important, human beings cannot technically sense humidity.
Reading the weight of a pot was guesswork at best, and often by the time a plant begins to show signs of distress, it’s too late.
Enter the sensor. Once I received my device, I started tracking the humidity drop over the days. I also tried to keep an eye on how different plants were drying out, not only at different rates but at different depths in their pots. I recorded the daily results of each plant in a notebook I had purchased specifically for this purpose so that I could track changes over time.
Most of the early results were not surprising. The top few inches of soil dried more quickly than the deep soil, which remained wet much longer.
Plus, early on, it was obvious how important soil type and composition was: the gritty, fast-draining soil in my succulent pots dried out much faster than the richer soil in my tropical plant pots.
Your cacti and succulents have different needs once you move them indoors.
Results after several weeks
I would love to say that I saved some plants that were yellowed and on the verge of death, bringing them back to verdant life, but the reality is that none of my plants were in such a desperate state. I just wanted a consistent way to avoid over- and underwatering and establish a reliable schedule. In this regard, the sensor was a resounding success.
By taking measurements in each pot over a few weeks, I was able to get an idea of how quickly the moisture drained from each pot. With this data in hand, I established a solid, data-driven watering schedule and created calendar reminders for myself based on what I learned.
You can’t really tell the humidity of that pot with your eyes alone – that’s where the soil sensor comes into play.
After three weeks, I see improvements, especially in the aforementioned orchid. Orchids are notoriously fickle when it comes to watering (and hold water very differently at different depths).
Proper watering has led to new leaf growth, and I’m even seeing buds sprouting on it for the first time since it initially lost its flowers several months ago. The aerial roots appear greener and healthier, and the leaves themselves are waxy and firm. (They were pretty droopy before this experience.)
I have also seen fewer yellowing leaves on some of my other plants. Overall, I’ve seen a big improvement in consistency. Whereas before, while some of my plants looked a little scruffy while others were relatively thriving, now they all seem healthy and well-maintained.
They are not my houseplants, but it is my goal to make sure mine thrive.
Although I will continue to check using the sensor from time to time, the benefit of this experience is that I now have a reliable timeline. So until I introduce new plants, I won’t need to continue measuring every day.
That said, the most surprisingly pleasant outcome of this whole experience was rather unexpected: confidence. Instead of the scattershot approach I took before, which left me feeling uncertain and sometimes even a little guilty when I watered (or forgot to do so), I now water my plants with complete confidence. I know I’m doing the right thing for their care and contributing to their health instead of second-guessing it, and it’s hard to overstate how much more I enjoy the whole process.
My orchids have really thrived thanks to this soil sensor.
In the end, it was worth it
So, was it worth the price and hassle? For me, the answer is a resounding yes.
Not only was the initial investment a very low bar, cost-wise, but running the test and tracking the results didn’t seem too complicated either. I actually had a lot of fun seeing the differences over time and between plants.
The analog sensor I got, although inexpensive, provided reliable and consistent readings and was simple to use. Simply insert it into the ground at the depth you want to measure and it will immediately display a result.
Again, the real benefit is confidence. Not only do I have a better idea of how much water my plants need and when, but I feel much safer every time I fill the watering can.
