Jacks 321 vs Masterblend/Calnit/Epsom salt analysis

Hollatchaboy said:

So chloride does no harm to plants?

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Dreddd said:

Hello everyone,
as someone that has been using Masterblend for years now with great results i decided to deep dive into the nutrient composition of both Masterblend and Jacks, both well known brands and i was wondering if anyone knows if theres any real difference between these two brands final recommended combinations, when i look at the nutrient breakdown on Jacks 5-12-26 formula:
View attachment 4578979
and on Masterblends 4-18-38:
View attachment 4578982
it seems like Jacks 5-12-26 is basically just Masterblends 4-18-38 with added magnesium sulfate, to the point where Masterblend has its own 5-12-26 product that is just the 4-18-38 + epsom salt premixed in it and looks almost exactly like Jack's:
View attachment 4578983

since both these brands instruct the addition of the same amount of calcium nitrate theres nothing interesting there so i wont mention it going forward just assume i include it, what i do find interesting and where the differences show up is the addition of epsom salt (magnesium sulfate),

if you use Masterblends 4-18-38 they advise that you add epsom salt at a 2 to 1 ratio, for every 2 gram of masterblend 4-18-38 add 1 gram of epsom salt, or if you buy the premixed version of 5-12-26 you dont have to add anything besides the calcium nitrate,

on the other hand with jacks 321 setup, you start with the 5-12-26 that already has magnesium sulfate in it much like the premixed 5-12-26 masterblend only jacks has a tad more magnesium sulfate 6.3%/8.5% vs masterblend 4.1%/5.4% and on top of this they tell you to add even more magnesium sulfate at a ratio of 3 to 1.

So which formulation has it right? should i be adding more magnesium sulfate to my Masterblend 5-12-26 formulation similar to the Jack's ratio? and since the 5-12-26 formulation is just the 4-18-38 with added magnesium sulfate at a 2 to 1 ratio does this mean that the touted 12g/12g/6g per 5gal of water that MPHgardener made so popular on youtube all those years ago should have actually been 12g/12g/12g per 5gal? or am i just not reading this properly and its actually the same for both brands?

thanks

PS: both these brands recommend a ph between 6.4 and 6.7 and yet i've been told again and again that cannabis needs 5.8 or no higher then 6, any thoughts on this?

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spek9 said:

Incorrect. All nutrients have an 'uptake window', whereby if the pH is too low or too high, that nutrient can no longer be uptaken by the plant, causing an artificial nutrient deficiency situation. You can add as much of that nutrient as you want, but if your pH is out of range, you're causing a toxicity situation within the medium while your plant can't use it. Each medium type requires a different pH range for maximum uptake of each nutrient.



That's incorrect as well. For one example, too much Potassium (K) can begin locking out Nitrogen (N), Calcium (Ca) and Magnesium (Mg). The effect of having too much of one nutrient causing the others to be reduced in uptake is called "nutrient antagonism". It's very complex trying to perfectly balance everything, but if one thing is too far off, other things can suffer greatly.

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plumsmooth said:

Any chance someone can help me figure out why I am getting a Potassium Defiency exactly at 2 weeks after the switch to Flowering Light cycle? I am tempted to try the Jacks cannabis Schedule of 10-30-20 for the one week without any Calcium although it seems counter-intuitive. Just wondering if I have a build up of Calcium antagonizing K?

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Rurumo said:

What EC are you running? I can almost guarantee you don't have a K deficiency, lockout is much more likely.

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plumsmooth said:

I actually lowered my E.C thinking it was accumilation which it might be. Because I do not change my reservoirs as often as I should. My plants in RDWC Power Growers drink up to 12-1200 In veg but as soon as I switch the lights -- it drops to about 6-700 PPM. I do not ever remember this happening now it alwasy happens around week 2 and then usually stablaizes? Sorry to hijack this thread...

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rkymtnman said:

one thing that is better about Jack's is that it's N is all from nitrate while Masterblend has 0.5% ammonia as it's N mix (cheaper source of N)

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OneHitDone said:

Have you ever used a mix with a higher ammonium content? Especially in coco? You should try it

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OneHitDone said:

Have you ever used a mix with a higher ammonium content? Especially in coco? You should try it

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2cent said:

Masterblend uses potassium chrloride and thats good for tomatoes.
But studys show tobacco anf cannabis is screws with them big time if ya cant find it il find the article on it on icmag bill farthings threads.
Defo do not want that on medi C

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plumsmooth said:

Can some one help me out please. I just mixed up Masterblend and compared to Jacks 3-2-1 Masterblend at 2-2-1 seems about 60-70 PPM less on my final reading? OR rather the difference between 480 and 420 PPM

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NeWcS said:

So with that in mind it'll always be stronger cause you use more.

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