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mrsgreenthumbs
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Epsom salts - why is it good and what for?

I was told a long while ago that Epsom salts were a miracle in the garden, then not long later I found some random site showing an experiment, one raised bed with and one without planted the same time, the one with the salts were double the size as the other.

Now I remember reading that Epsom salts were not salt at all but minerals. How do the minerals help and what plant would be adversely affected by an occasional sprinkle of this supposed miracle helper commonly found (at least in my house) in the bathroom of all places?
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garden5
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Epsom salts contain magnesium and sulfur, two components that contribute to better blooms, stronger plants, and it supposedly allows the plants to undergo photosynthesis better. Here is [url=https://www.epsomsaltcouncil.org/garden_why_it_works.htm]how it works[/url] and [url=https://www.epsomsaltcouncil.org/garden_usage_tips.htm]how to use it.[/url]

However, I believe that I have heard that it may harm the soil biology. Also, I have heard that it sometimes does not have the benefits that some say it has. I'v never used any, myself, so could anyone with some experience with it weigh in? Has anyone actually done a split-test with them?
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mrsgreenthumbs
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It's an intriguing topic to me simply because I'm a fan of ANYTHING that does double duty around my house. And it gives me an excuse for a long QUIET bath ;) have to find some kind of use for all that salt right? :cool:
Words of wisdom from the women of my family:

"I poured my dish water out the pan over my plants and never once in all my 96 years have I wasted money on "BUG SPRAY"!'

"Aww honey all you gotta do is love something to make it grow."

Bud
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I have only heard of it being used in growing tomatoes. I sometimes put a litttle in the hole before planting my tomato plants. I think it helps but I'm not sure!

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rainbowgardener
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There's an epsom salts thread in the Tomato forum here:

https://www.helpfulgardener.com/forum/viewtopic.php?t=4239&postdays=0&postorder=asc&start=15

It's an old thread, recently resurrected. You will see lots of different opinions there.

Most organic gardeners do not use epsom salts. They are a salt (chemically- not sodium, not table salt, but they are a salt -- technically , salts are ionic compounds which can result from the neutralization reaction of acids.)

"Epsom Salts' (technically Magnesium Sulfate, or MgSO4) is one of just a few water-soluble Sulfate minerals, and it is a soluble salt -- a salt that dissolves in water. ALL chemical fertilizers are also 'soluble salts'. When Ammonium, Potassium, Chloride or Nitrate dissolve in water, they are soluble salts. A little will fertilize the plants. Too much will damage and sometimes destroy a plant. That can happen quickly --or it can take time and build up slowly. THERE IS NO DIFFERENCE BETWEEN YOUR USE OF EPSOM SALTS AND THE USE OF A CHEMICAL FERTILIZER LIKE MIRACLE GRO. Because ALL chemical fertilizers ARE SALTS. Salts KILL microbes in your soil. I love my microbes. I love my soil foodweb. I love all the beneficials down in the dirt. One teaspoon of healthy soil holds MILLIONS of friendly microscopic organisms. If salt hurts my microbes, it's got to go." from https://en.allexperts.com/q/Fertilizer-717/EPSOM-SALT-HYDRANGEAS.htm

TZ -OH6
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Magnesium is an important part of enzyme cofactors in plants, and secondarily, it is a component of chlorophyll. By the time the plant starts to yellow it is down to something like 25% of its optimal magnesium level. Among other things, magnesium containing cofactors help in the enzymatic process of sugar loading from the leaves into the plant's vascular system, especially in cool weather when enzyme activity is slowed. Magnesium deficiency is one reason why plants often turn reddish in cool weather. Ther red pigment is a sunscreen to slow sugar production/photosynthesis, because excess sugar in the leaves starts to cause problems.


Inlike most fertilizer salts, magnesium sulfate is tolerated by plants in extremely high concentrations, which is why you will commonly see recommendations as high as two tablespoons per gallon of water. Unused magnesium is stored within the cell vacuoles so you do not need to give the plant frequent doses. Orchid growers generally apply it four times a year. You do not want to mix it in with fertilizer because the sulfate binds to calcium and precipitates out as white crusty gypsum crystals on top of the soil, around the holes in pots, etc., depriving the plants of both the calcium and sulfur.

Epsoms salts can leach out of the soil pretty quickly, and spring soil should have plenty of magnesium for small plants, so adding it to the planting holes is not the most efficient method of application. It is when the plants are growing fast and producing alot of fruit that the plant may become magnesium limited. Epsoms salts can be applied as a foliar spray or to the roots. When the lower leaves of the plants start to look yellow with red/purple veins I generally just sprinkle Epsoms salts on the ground near the base of the plants and water it in.


Adding dolomitic lime to your soil, if the soil is acidic, should circumvent the magnesium problem long term, but if you have basic soil, Epsoms salts might be a better approach.

garden5
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Wow, two really good perspectives.

TZ, do you agree that the Epsom salts can and will kill the microbial life?
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TZ -OH6
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Short answer…Not in the amounts you would normally use, and if some microbes were killed on contact by the salt crystals due to osmotic stress (the same way they would be with sugar crystals), more microbes would reproduce and replace them as soon as the concentration was diluted down some. Gypsum (Calcium sulfate salt) is an organic soil additive, as is limestone (calcium carbonate salt) and dolomite (magnesium carbonate salt). These are sold in 40 lb bags to mix in with your soil, so a cup full of magnesium sulfate (Epsom’s salts) spread out in the garden is not going to wipe out the soil life.

Pretty much anything that is nutritional to plant life is nutritional to microbes. On the other hand, not all “certified organicâ€

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