Moisture metres are a pretty divisive tool in the house plant community and for good reason.
They’re one of those things that would be genuinely life-changing (in terms of plant care at least) if they actually worked as they claim to but they, er, don’t.
This is why a lot of people hate them. And I get it. I really do.
Moisture metres are inaccurate. They’re a guide, and they work best in suboptimal conditions.
But moisture metres are fantastic for house plant beginners.
Here’s why house plant beginners should get moisture metres
First off, they’re cheap.
I was originally gonna make this a moisture metre review article, and compare all my various metres.
To be perfectly honest, they’re all equally great for dense soil and crap for airy soil. Get a cheap one – the pricey ones aren’t worth it in my opinion.
But however cheap they are, if they don’t work, why bother?
So moisture metres are great for airy, homemade soil, and they’re not that accurate
EXCEPT
A lot of house plants come in very dense soil OR the plant newbie accidentally reports the plant immediately in a dense soil mix they bought at the garden centre.
Moisture metres are great for dense soil. Dense soils hold on to a lot of water for a long time. Newbies water a lot.
A moisture metre is a great way to understand just how wet soil can stay, especially if you start your collection in winter.
Whilst I don’t really use a moisture metre now, they were eye-opening when I first started caring for my plants properly.
Moisture metre review
This isn’t really a review because tbh I don’t think it really matters which one you buy. Honestly, just get on that fits your budget – they all work the same way (something to do with the metal prong conducting water).
One thing I will recommend is to try to avoid the ones with two prongs. I have one and it’s FINE, but with two prongs you’re twice as likely to damage a root. Also, when you pull the metre out of the soil you can end up flicking the soil about more than with a one prong.
I have a fancy one with batteries and a digital display. Again, it’s fine but no more accurate than one with a wobbly dial.
If you want to know what number you need to be watering at, I have an article on that here. If there’s a plant that isn’t on there, leave me a comment and I’ll add it.
Don’t rely on moisture metres for accurate pH or light readings either.
If you want to test your pH then get a soil pH kit. This isn’t something that you really need, but if you’re interested, get the proper kit.
As for light meters…I wouldn’t bother. I’ve tried all the apps and they’re so inaccurate.
Are fingers more reliable than moisture meters?
One of the common responses to ‘should I get a moisture meter?’ is for people to shit all over moisture meters and instruct the user to use their finger to gauge how wet something is.
I mean, yeah, it works, but also…not always.
Wet soil feels wet, but damp soil doesn’t always. Also, how damp is it? Our fingers don’t have a numbered scale, and if we’re new to plant care we have no idea what we’re meant to be feeling for.
Using your finger isn’t always practical either – I ALWAYS notice that a plant looks dry when I’m:
- rushing out the door and don’t have time to wash my hands
- have wet nails
- am wearing white
This may possibly be an exaggeration, but also…it’s simply not always practical to be going around sticking your finger in dirt.
Skin is weird too. Once you stick your finger in wet soil, however much you dry it, the next bit of soil will feel damp.
We’ve not even mentioned those of us with massive pots.
Is this really gonna give an accurate reading of how wet the soil is in the middle? No. What am I meant to do? Grow massively long fingers?
One of the beauties of moisture meters is that they’re pretty good for large pots. One, because they’re long, but also because there’s more soil, so it’s more compacted, and therefore the moisture meter MAY be more accurate.
By the way, see that weird drip on the side of the pot? It’s like amber, and quite beautiful when the light hits it, but…weird. Rock hard and it won’t come off.
Final thoughts
I’m not evangelical about moisture meters. I’m not insisting that everyone needs one, but i don’t think they’re a terrible tool. I certainly don’t subscribe to the ethos that they’re actually damaging to plants.
As long as you’re aware that they’re not actually going down in the soil, having a look around at the dirt and the roots and going ‘hmm, yeah, I think we’re at about a five here’.
What they’re actually doing is going into the soil and going ‘WATER IS NOT TOUCHING ME’.
Me: but is there water being held in the soil?
Moisture meter: there’s no soil here, only air
Me: I mean, there is, I can see it
Moisture meter: A BIT TOUCHED MY FOOT
Me: was it wet
Moisture meter: EEEEEEEEWWW GROSS
Me: WAS IT WET???
Moisture meter *shrugs*
In short, the denser the soil is, the more accurately the meter can measure moisture in the soil, but also dense soil means a higher chance of root rot. But if you’re using a moisture meter regularly and are a helicopter plant person, you’re less likely to overwater anyway.
This is how some people have incredibly healthy plants in regular outdoor potting soil.
