Fox Farm to Jack's 321

Hello I hope everybody is doing well. I have a question about Jack’s 321. I’m currently using Fox Farm Trio in soil. I would love to switch to Jack’s 321 but I’m not quite sure which one to get? I keep hearing everybody talk about Jack’s 321 where you feed the same ratio from start to finish. I’d love to try that. Can anybody tell me the correct one to get? Thank you very much for your time I do appreciate it

These are the big bags but this is what they look like. The third part is just plain epsom salt you can pick up at a grocery store


Bobby digital what’s up brother. already got the Epsom salt at home :slight_smile: thanks again man I appreciate it.

Anytime. If you don’t have the feed amounts it is:

3.6g part A
2.4g part B
1.2g epsom

Per gallon.

You can mix the part A and epsom together in the water but must wait for it to fully dissolve before adding in the cal nitrate (part B).


And then you would adjust accordingly the ph of mixture?

Correct. With my tap water (7.4ph, 250ppm) it settles at 6.53 so I don’t even need to check ph.

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Thank you I appreciate that. Thanks again we’ll see you around. Happy growing


Started using Jacks on my current grow…
Im not going back…Its great


Here’s mixing video that’s short. They show 1.1 grams of Epsom, but most will do 1.2 or a little more. I recently bumped mine up to 1.3 grams per gallon.


I was having issues adjusting ph with foxfarm and I am not sure that my ph pen was accurate or ever calibrated correctly. Currently I’m running AN it’s a bit pricey but takes the guess work out of adding ph up or down to get it right

I had to run 2g for my gold leaf. GDP was fine with 1.2g

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If you dont mix it right does it blow up or something IE the desolving part???

yes! Very dangerous, lol. The cal nitrate and magnesium sulfate can bond and now you have calcium sulfate which is basically gypsum and not soluble.

Oh…ok…I think. Lol

@BobbyDigital. At what point do you start feeding with the jacks???

When my soil gets down around 1000ppm.

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Ok just like the FFOF then. Your ph and TDs numbers are almost identical to my tap. BTW just transplanted today

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@BobbyDigital Do you use the 10-30-20 Bloom and the 7-15-30 Finish at all and if so how do you incorporate them into the 321 formula or are they necessary?

I don’t. I just use part A and B and epsom salt. I have used fox farms dry pk boosters with it but didn’t really notice any difference.

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Thanks, man I appreciate it I ended up buying their starter kit that comes with part A, B, and Epsom salts as well as the bloom and finish also comes with a cloning mix as well I may have to experiment with the bloom and finish to see if I get a difference in yield or quality in the end

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