Jacks nutrients!

Okay y’all I’m back and I got jacks part a and b was wondering how I use it? @Covertgrower


This is the ratio. The order is important!!!
Part a first then epsom salt then part b
3,1,2 instead of 321
I’m using this in coco and loving it. Soooo easy and plants are loving it. Even using it on rest of garden


If you go to the Jack’s website it will tell you the sequence which is in fact A, B and Epsom. Any silica or cal mag is mixed in first. Once part A is dissolved you can mix part B and Epsom at the same time.


If you dont want to weigh the powder which is difficult unless you are doing 5 gallons or more then just use 1/2 tsp of part A, 1/4 tsp of epsom salt, and 1/2 tsp of part B. You can add Part A and Epsom Salt at the same time and mix well, then add Part B. Mix well. Then adjust pH.

I use jacks they emailed the ratios to me 3/4 part a 1/2 part b and 1/4 teaspoons per gallon to cheap to buy another Scale :v:

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Do you measure the weight of the dry amendments , spread over soil and water in , or you mix in gallon shake and pour ?

I have increased my epsom salt to 1.5 grams per gallon.
Nice to have you back on the forum @Katyp !


I have found that there is some room for error in these measurements.
It seems to be very forgiving.

Mix in water

You legit use a scale to measure that shit? Lol okay just checking and glad to be back! I miss my direct connect tho!

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I add these before adjusting the ph?

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From the horses mouth. Copied from Jacks Nutrients / Jacks - 321

Jack’s 321 is our tried and true two-part fertilizer program.
It consists of Jack’s Nutrients Part A 5-12-26, Jack’s Nutrients Part B 15-0-0 and Epsom Salts. BUT where does that “321” come from, you ask? It’s the shortened amount of each fertilizer in grams per gallon.
To mix up the perfect blend of Jack’s 321 you will need:
3.6 grams Part A

2.4 grams Part B

1.1 grams of Epsom salts​

This will give you a blend of nutrients for growing almost any controlled environment crop, in any growing system. The order of additions is VERY important. You must add the 5-12-26 first and make sure it is completely dissolved, then add in the Epsom salts making sure it is completely dissolved, then finally the calcium nitrate.

I remember the mix order as A E B or 312


I’ve been using the Kootmed schedule as it turns out. Jack’s lists your mixing order on their website. That said I’ve been dumping Armor Si, Part A, Part B then Epsom with no ill effects and crystal clear solution


Always adjust the pH last.
Anything added afterwards would change it.

Its a forgiving system.
I have been mixing A and Epsom at the same time and then B. In RO water I hit 5.8 without any anjustment.
Plant is in Coco and its doing great.

This is how I use it.

My muni water is funny: 130 ppm but 8.5 PH: I add silica then PH down. Then A, B and Epsom. Or in my case right now I’m on the 2-2-2-1.2 MKP schedule for 3 weeks.

Yes I do. This keeps me from adding any extra just because… haha.

Anyone know where to buy jacks in Australia?:australia:

Anyone know where to purchase Jacks A and B.? Amazon only seems to have part A and I really don’t see the kits labeled on their website as “A” and “B”?