Jacks 321 vs Masterblend/Calnit/Epsom salt analysis

brjsg2

New Member
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 :D

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?
Hi! You say that MB 4-18-38 + Mg Sulfate (2:1) = Jacks Hydro 5-12-26 formula but I cant understand how does the additional Magnesium Sulfate increase Nitrogen Potassium and Phosphorus percentages.

If anyone can explain me! Thanks :weed::weed::weed:
 

plumsmooth

Well-Known Member
Anyone else realize that the 3-2-1 is really closer to a 3-2-.5 than a true 3-2-1? I think I calculated 3-2-.64 approx?
Don't you think a 3-2-1 is too much Magnesium especially if topping up on a recirculating system??
 

plumsmooth

Well-Known Member
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.
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?
 

Rurumo

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

plumsmooth

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

plumsmooth

Well-Known Member
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...
P.S> I also think the lower leaf Surface Temperatures I have running my bright Scorpion Diablos vs CMH might be affecting Transpiration and hence potassium. But in VEG my plant to find with lower LST?
 

amneziaHaze

Well-Known Member
I just add pk from hesi in flower. But for veg it depends on the plants usually its the amount it says on box they make 600ppm but some strains couldnt handle it had to go half and some strains wanted 1.5
 

NeWcS

Well-Known Member
Here is a side-by-side between MB and Jacks. I don't see a a big difference, just that Jacks formula has tons more mg and sulfer.

Masterblend: MB 2.4g, Calnit 2.4g, Epsom 1.2g
Jacks: Jacks 3.6g, Calnit 2.4g, Epsom 1.1g
 

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f.r

Well-Known Member
Have you ever used a mix with a higher ammonium content? Especially in coco? You should try it :peace:
Too much ammonia can affect cannabis flowers.

A little bit to balance PH in the medium for coco is good imo! I currently only use nitrate nitrgoen but want to buiy a bit of mono amonium phosphate to add to my mixes.
 

Mike Parent

Active Member
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
Which studies? TIA
 

plumsmooth

Well-Known Member
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
 

NeWcS

Well-Known Member
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
Are you using their 4-18-38(2.4 grams) w/ calnit(2.4 grams) and Mg(1.2 grams)?

With Jacks you're using more base. I believe it's 3.4, while the other 2 ingredients are the same'ish. So with that in mind it'll always be stronger cause you use more.
 

plumsmooth

Well-Known Member
I have been for a while premixing my Jacks at 250/165/64 Grams respectivly in 1000ml or a Liter of Water.
Then I usually fill my Watering Container with a TBl of each. When I mixed my Masterblend I just matched the 165 to the 165 of Calcium Nitrate and used the 64 Gram per Liter Mg I already had mixed (maybe too little Mg) for the jacks. I expectied the Numbers to be closer. 4-18-36 compared to 5-12-26 seemed about a 1 to 2/3 ratio to me. IT made me concerned that I either mixed one of the ingrdients wrong.
 

plumsmooth

Well-Known Member
The other thing that still bothers me is I don't understand How Jacks 3-2-1 which is already some think too much Mg got rounded up from what should be closer to 3-2-.64 if you look at their chart. To me that seems like some lazy hippie math round up for some kind of Sensationalist numerological symmetry lol...
 
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