Using epsom salt in hydro

Vlad the Inhaler

Active member
I hope everyone is well
I want to add some mag to my mid-blooming plants.
Went to my local today to buy HnG 8%, but they are waiting to restock.
I'm thinking to put Epson salt into my irrigation at about 1-2grm per 30L, and use it for at least next week
Has anyone used it as a Mag supplement, and can reccomendd dose and usage please.
 
I can't work out the actual Mag content in Epsom ( monohydrate )
Best I can work out is about 10%.
So 1grm would provide 100mg Mag.
I think I'll use 5grm/30L run to waste.
Can anyone chip in with the mineral breakdown of Epsom salt?
 
Kia Ora,

Epsom salt = MgSO4 or Magnesium Sulfate, I've seen the magnesium content listed anywhere inbetween 9-15% and the sulfer content between 14%-20%.

Epsom salts is what's commonly used for magnesium and sulfur in hydroponics, I mix my MgSO4 into a stock solution and measure out the PPM but I've been told it's safe to supplement with Epsom salts at about 1/2 tsp to 1 tsp per US gallon.
 
Kia Ora,

Epsom salt = MgSO4 or Magnesium Sulfate, I've seen the magnesium content listed anywhere inbetween 9-15% and the sulfer content between 14%-20%.

Epsom salts is what's commonly used for magnesium and sulfur in hydroponics, I mix my MgSO4 into a stock solution and measure out the PPM but I've been told it's safe to supplement with Epsom salts at about 1/2 tsp to 1 tsp per US gallon.

Sweet as, thanks man.
9-15% sounds about right because the hydrate forms all carry different amounts of water bond.
The anhydrous would be 15.
I found the solubility/absorption rates and looks like HnG 8% is just a saturated solution of Epsom salt.
A kilo of powder is about $3 and that product is $40+ so it's a nice alternative

Thanks for the input
 
I use a gram per gallon of Epsom salts and it gives a reading of 40ppm.
I use calnit,Epsom,and 3rd part powder mix known as jrpeters 3:2:1.
If my plants need extra calcium I boost calnit and if more magnesium is needed I boost Epsom by 1/2 gram increments.
Be careful adding teaspoons because clumps of Epsom can look small but are much heavier and can raise ppm too high locking out calcium and nutrients.
 
by mid bloom the usage of magnesium by the plant is greatly reduced, what makes you think you should be adding it at mid bloom?
 
Hi.
One of my plants has really tiny calyx. It's more vigorous and later than the rest so I had to trim her at start of flower.
Her bottom leaves started to fade away, but with no spotting or burning to tip or damage on blades.
I thought there is no calcium issue, and the chlorophyll was disapearing. They are being fed enough N, so I guess she wanted more Mag.
I didn't add it yet, because the others rnt fading.
I'll probably just top dress this one bucket if it gets worse
 
I use a gram per gallon of Epsom salts and it gives a reading of 40ppm.
I use calnit,Epsom,and 3rd part powder mix known as jrpeters 3:2:1.
If my plants need extra calcium I boost calnit and if more magnesium is needed I boost Epsom by 1/2 gram increments.
Be careful adding teaspoons because clumps of Epsom can look small but are much heavier and can raise ppm too high locking out calcium and nutrients.

That's good to know, I never measured out the gram to litre/gallon ppm, I make my salts into concentrates, for me it's easier to do the math once then just add x/mL per litre, I'm to lazy and impatient to check ppm with a meter every feed.

Your in coco right Vlad ? Did you try a little cal/mag? It could be you need more calcium or less potassium, which ever works better, if you have to much potassium to calcium you will get cal/mag like deficiencies from a potassium toxicity which seems common in coco.

I don't think it will hurt you to try a little boost of Epsom salts anyway just maybe don't use a tsp per gallon like I suggested and go with what Indi said.

Do you have a EC/ppm meter ?
 
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Yeah I have a ec meter. In mid stage I went up to about 1450 tops.
They r doing pretty well so didn't need any more.
They rnt acting poorly, or really need anything extra.
Mag is important to terps, oil and density, so I wanted to work out how to use it independant of cal/Mag sups.
I've used canna pro coco that's buffered, coco grow and bloom from a really good Aussie chemist used to coco.
Also used two cal/Mag products ( one is humus+, other straight calmag/fe. )
I found at first I was getting potassium lock out from too much cal.
Upped kelp and nk+( potassium humate 4-0-9.
After about two weeks the coco gives up a bit of potassium, so it didn't show again.
Small leaves and red stem normally.
Once the internodes really stretched. It looked like it was growing quickly, but the tips weren't really going.
That was worst, but just one plant did that, and that was when I first started.
 
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