What's the Latest Numbers on Jack's 3-2-1?

Is anyone else confused with the numbers being tossed around concerning Jack's 321? Instead of 321, the corrected version is 3.78-2.53-.99. Now I hear 4.2-1.65-1. Does anyone know the optimum formula?

I think with the new fed rates it's around 3.9/2.8/1.5 but I have no idea if it will hold

I use this always mixing 5-12-26 in to water first
No clue why I would change

3-2-1 is just the ratio used. And 3 grams Jacks 5-12-26, 2 grams cal-nit and 1 gram mag/sulfate seems to be plenty for most of the plants Ive grown. I ran a pure sativa all the way through and only used 50% (1.8-1.2-.6) I still got some brown tips and minor clawing at that strength.

Last I checked the web site it was 3.79-2.52-0.99

[checks web site]

They've "improved" the web site (it's harder to find the schedule for 3-2-1)

The formula for RO is as shown above. Google "jacks 3-2-1 for cannabis" and poke the link with this text "Cannabis and Hemp Schedules - Jack's Nutrients"

Herb & Suds said:

I use this always mixing 5-12-26 in to water first
No clue why I would change
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that is interesting about the finish formula recommendation to run for 1 week pre-chop. makes more sense than cutting N as early as some do.

I used to run jacks at 3.0/2.0/1.0 grams per gallon before I switched to mixing it into stock concentrates and just using it like it was a bottled nute.

It really depends on your humidity and light. I’m slowly testing on some clones and seedlings full strength. My RH is up there 60-65. Feeding around 1000ppm. Close to the 3.6 2.4 1.2 and they are fine. But it’s pushing the line. If you let them dry out you will see over fertilizing or your rh drops bad news.
Start low and ramp up once every few days and read your plants.

waterproof808 said:

I used to run jacks at 3.0/2.0/1.0 grams per gallon before I switched to mixing it into stock concentrates and just using it like it was a bottled nute.

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What stock ratios do you use?

Gemtree said:

What stock ratios do you use?

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I use the recipe printed on the bag, its still a 3:2:1 ratio:
-13oz Part A + 4.3Oz Epsom Salts in One Jug
-8.6oz Calnit in a separate jug.
~35ml of each per gallon in the rez.

Thanks for all the replies and suggestions. My purpose was to find the right numbers for a 100-1 ratio stock solution. I'm sure all these ratios will grow fine Cannabis but I need to start somewhere and modify down the road as needed. Some plants are Ace Sativas that will be a bit fussy on the nutes based on past experience.
I will use the 3.67-2.52-.99. First I will mix the epsom in a gallon container half-full with water. Shake to mix. To the same container I will add 367 grams of NPK, shake and fill with water. 252 grams of Cal. nit. goes into another container by itself. Just got these 25 lb. bags of Jack's which will last a loooong time.

I can’t seem to figure out how to add Cal mag into my Jacks program. I was told to add .3 EC to each watering but I’m not sure how that plays into my target cc when adding each part. Below is a feeding chart that I made the way that I can understand it. Such as My water is .1 EC and the Cal mag would be .3 EC so now the target a C after that would be .4 but now I don’t understand the ratios of how to mix jacks to get to the proper target EC for each part. Can someone help me fill this chart in?