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I need to start this by saying that I’ve never used Epsom salts on my plants, because, from the research I’ve done, they can do more harm than good, and the good they do isn’t exactly life-changing.
The studies I read all largely came to the same conclusion: there might be some benefit to using Epsom salts on your plants, but you’d be better off getting a product designed for whatever problem you’re trying to fix.
It’ll yield better results, and you’re less likely to damage your plants.
If you want to try them, go ahead. Unless you waaay oversalt them you probably won’t kill your plants, but you also won’t really benefit them either.
Your plants have a magnesium deficiency. We’ll talk more about that later.
What are Epsom salts?
Epsom salts are another name for magnesium sulphates (they’re also known as bath salts, bitter salts, or English salts). It’s a naturally forming material. They’re soluble in water, but do NOT confuse them with table salt. Though many people swear by them for various ailments, tasty they are not.
Did I try some for the purpose of this article? No. I love you, but not enough to eat gross salts. Also, they’re commonly used as a laxative, so, er, let’s not randomly try them.
When Epsom salts are dissolved, they release magnesium ions, and it’s the magnesium that Epsom salt imbibers are after. You can absorb magnesium through your skin (hence putting Epsom salts in the bath), but it’s apparently better absorbed when taken by the mouth (though yakky).
By the way, there isn’t much (if any) evidence to suggest that this is a good way to get magnesium into a human, so it stands to reason that there’s even less evidence to suggest that it’s a good way to get magnesium into plants.
Which plants like Epsom salts?
I wouldn’t go as far as to say ‘X plant would benefit from Epsom salts’ because there really isn’t enough evidence out there to say that they do ANYTHING.
There is a LOT of anecdotal evidence to claim that Epsom salts work wonders for plants, but you need to be so careful with taking advice from other plant owners.
When I was researching an article about speaking to plants a lot of the people who claimed it helped their plants were spending HOURS talking and singing to their plant.
I came to the conclusion that whilst the talking might have helped, the hours they were spending observing their plants was probably the main reason their plants were thriving.
If you’re curious about using Epsom salts, try using it on a plant you suspect has a magnesium deficiency.
How to tell if your plant has magnesium deficiency
Of course, it can’t be easy.
I mean, why would it be?
In an ideal world, magnesium deficiency would manifest itself in a clear way, such as developing pink spots, or blue stripes or something, but NO.
Magnesium deficiency in plants presents itself as yellowing leaves.
I have an article that outlines all the reasons why your plant may have yellow leaves. Magnesium deficiency isn’t the main player by any means. You’re going to have to check whether your leaf is old, you’ve got root rot, nitrogen deficiency, or one of the many other reasons for yellowing leaves.
If you also consider that adding Epsom salts to an already sick plant might hinder it even further, the inevitable conclusion is that…maybe there’s a better way to add magnesium to the soil. Perhaps a really gentle 9but balanced) fertiliser (ensuring it has magnesium added).
Will Epsom salts harm house plants?
Probably not, unless you’re adding them really liberally BUT there are things to take into consideration. Studies show that adding magnesium to soil that’s already magnesium-rich can inhibit calcium absorption.
There is also evidence that Epsom salts can cause leaf scorch and even root rot.
Can you add Epsom salts to potting soil?
Technically yes, but you can add whatever you like to potting soil. Should you? I wouldn’t recommend it. If you’re worried about your soil being nutrient deficient, I’d add some worm castings or a well-balanced house plant fertiliser.
What is the Epsom salt dosage for house plants?
I’m just going to link to a more pro-Epsom salts article here because it’s disingenuous of me to give you a dosage when I don’t really think you would be adding Epsom salts at all.
Whilst I don’t agree with the article in the most part, I’m pleased to say that they do recommend that you test your soil before adding Epsom salts, to check that your plant is really magnesium-deficient. So yeah, so that. You can get soil testing kits on Amazon.
Can too many Epsom salts hurt plants?
Yes, which is one of the problems I have with the article I linked above, as they claimed you may as well try Epsom salts as ‘they won’t harm’ your plant.
Too much of anything can harm plants (remember overwatering? Who would have thought that was a thing prior to getting into plants?), and Epsom salts are, after all, SALTS.
When to use Epsom salts for plants
I jest, I jest.
There are a tonne of claims out there that Epsom salts can help with flowering, germinating seeds, and various other issues.
From what I’ve read, the only thing Epsom salts can unequivocally help with is magnesium deficiency, and you need quite a lot to make a difference (especially with outdoor plants).
Just get yourself a decent house plant fertiliser.
Can I sprinkle Epsom salts around plants?
I mean you can, but it probably won’t do any good. Epsom salts only release magnesium ions when they’re diluted, and if you add raw (?) salts to your soil and water it in, you’ll likely just wash most of it away.
Can I use Epsom salts as a foliar spray?
Again, I would prefer to buy a foliar spray designed for use on house plants. I use an orchid one but I only have one to test out if it actually does anything. You can also dilute your regular fertiliser and use it as a foliar spray, though I’d recommend finding a pretty natural one (such as seaweed) and remember that the smell will last longer than it would if you were watering it into the soil.
The danger of foliar sprays is that they can cause leaf scorch, which is why I think it’s so important to use one that’s formulated for plants. You still need to be careful about leaving a sprayed plant in the sun, but at least you don’t need to worry about the dosage.
Aaaaand if you do everything right and you still get leaf scorch, you’ll be able to complain to the manufacturers.
Since I don’t use Epsom salts on my plants, I had to do my own research on them before making up my mind. I honestly didn’t intend for this to become a full-on Epsom salt bashing session, but also, I don’t want to encourage people to damage their plants.
If any of you swear by Epsom salts, I’d love for you to leave a comment with a few details about what you use them for, how you use them, and the benefits you’ve seen.