Jacks 321 mixing question

I have been gone from the forum and growing for a year for personal reasons. I am glad to finally be back to doing what I love. I am using jacks 321 in autopots. This is my third run with jacks and have had excellent results. I travel a lot and am gone for periods of a week or so now. I have my setup to be as automatic as I can right now. My plan is to use a separate 55 gallon reservoir to keep my nutes pre mixed in so I can just add to my system reservoirs to top them off when needed. My question is after the first initial mixing of the storage container if want to add to it without completely emptying it, it will have solution in it, can I mix straight into it in the right order or will I have to mix the solution in separate containers in clean water? Because of the part a and calcium nitrate not being able to mix without being dissolved into water first. I hope this question makes sense enough lol. Thanks for any responses and happy growing.


That is a damn good question!

Following to listen to answers…

1 Like

I don’t use auto watering, but if I was, I would mix it up outside res. and put in after mixing, just my 2 cents.

1 Like

i would not do my mixing in a big batch of already made jacks. i would always mix with clean water. keep a 5 gallon bucket and add 5 gallons at a time is my suggestion.


Question for yas using Jack’s is it supposed to have white chunks in the part A thanks.

Mine does, the 2 pound bag I originally had, also in 25 pound bag I recently received.

1 Like

It will until it is fully dissolved. Just make sure it is all dissolved before the cal nitrate is added.


I am but when looking at the mix it looks like brownish cool powder and looks like big white chunks.

Color powder and thanks for the reply.

here’s my jacks part a

1 Like

Do you experience much Ph rise in the reservoir solution? I have a the small autopot res. There was about 2 gallons left in it and figured I should see how its Ph is doing. I increased to 6.4 from 5.8-5.9 over the past 4 days. I adjusted it back down to 5.9.

This is what it looks like.

6 pound kit from ebay

1 Like

My jacks mix is usually good for a day. Day 2 after mixing the ph starts to rise. I’ve no idea how fast or how far after day 2 because since I know this……

Show us the plants :potted_plant:, we want to see the baby ladies ?

Jack’s recommends letting the Part A and Epsom dissolve fully before adding Part B. There’s some chemical bad-things that happen if you don’t. I don’t have to understand the interactions, I just have to mix-wait-mix to avoid the bad-things. If you’re like me and don’t understand the chemistry you’re best off not taking chances. Mix everything up offline and add the final solution to the reservoir.

@beardless Yes it will rise always. I ph a little low and let it rise to swing to alow the plants to access all nutrients at the ph levels they are available. I start at 5.5 to 5.6 and let it rise. I usually stops at 5.9 to 6.1

1 Like

The rise is common and is a normal occurrence. I did what I usually do. Pull a sample and check the numbers and adjust as necessary.


@yoshi I will post some tomorrow.

I only have two pots going this time so I am not mixing large quantities. I was aware of starting lower to account for the rise but have been hesitant to try it. It does make sense though. I’ll give it a try when I replenish the reservoir. It probably be around 14 liters.