I’ve always used Fox Farm and have never gotten through a grow without having to do a flush to eliminate salt buildup. It it the same with Jack’s, or is it not a salt based fertilizer?
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Jacks I’ve never had to flush. I don’t flush before harvest either. I’ll feed just water the last few weeks. I think the amount of nutrients is a low enough, that the build up doesn’t happen.
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It is a salt based fertilizer.
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I use FF and never have to flush until the very end. I always water to around 20% runoff every single time.
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Like @Covertgrower mentioned with Jack’s the last 2 week you just water it with no nutrition. I find it easy 2 mix and the amount your are mixing is not alot either
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I use jacks exclusively and nothing builds up due to watering with a lot of runoff. Even in my soil grow in 10 gallon bag when I water which is every other day now I water til I get a substantial runoff so won’t ever have to flush.
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I switched to Jack’s from FF, same ratio from beginning to end. Just about to start another grow with it as I’ve had no issues with it just solid buds.
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Yea ive fallen into love with jacks to my only problem is its a Lil to nitrogen heavy near the end but you just add monopotassium phosphate ( mkp) at a adjusted amount and they love it. No sign of salt buildup heck even the bottom of my fabric pots haven’t even gotten that salty
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I looked on Amazon for Jack’s and a bewildering number of options. I understand that Jack’s is a 2 part product for cannabis, so my question is, which 2 of their products should I be buying?
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They sell 25 lb bags which will last a while. 
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Jack’s 321 part A and part B and epsom salts. I believe they have 2.5 lb bags you can buy direct form Jacks.
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Found them. Thanks. I’m going to throw out my FF and begin Jacks for the next grow.
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I honestly think you’ll be happy with that decision. And don’t forget the Epson salt which you can get at most grocery stores or Wally World. Good luck!
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Yeah, I’m getting a little frustrated with having to flush twice per grow. It’s time consuming and messy.
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I’ve got some Epsom and feed it occasionally.
I assume it’s 1 tablespoon of both A and B each feeding (+ Epsom)?
I would pick up a small scale. It’s measured in grams.
Part A 3.69 grams/gal.
Epson Salt 1.2 grams/gal.
Part B 2.44 grams/gal.
Mixed in that order. Making sure each part is mixed thoroughly before adding the next.
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We bought the 25 lb bags for about 60.00 each so 30to 40 bucks for 2.2 lbs seems really high.
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There is no planned/scheduled flushing throughout grow required. Using 3-2-1 ratio isn’t typically excessive ppm to the point where you should need to plan on running a flush. If you choose at end of harvest I would treat the same as you would any other synthetic nutrient package. Same goes for running into extremely light or heavy feeding plant. Most will find following the ratio above balanced and satisfactory for most plants, and ph swings aren’t typical.
Long before jacks supported cannabis and there was a part A and part B we used same recipe with bags of jacks professional hydroponic blend 5-12-26 (part A) calcium nitrate (part B) and fragrance free magnesium sulfate (epsom salt). You can control nitrogen and calcium levels by increasing/decreasing calcium nitrate and magnesium by adjusting epsom salt. If you want to tweak phosphorus or potassium would be better to get monopotassium phosphate and/or potash blend, but that shouldn’t be necessary to have a good experience.
Check local or other online distributors for pricing. 2 pound packages from Amazon aren’t typically the best value.
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I run jacks and got a 7lb kit that cost $40 on ebay its definitely worth it. It comes with everything and will last you awhile
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Hope you don’t mind me jumping in?? I switched from Jacks 321 to Jacks for Tap. My tap has a PH of 7.2 (not bad) and 40 PPMS, not so good for needed calcium. Jacks for tap has included that in their base and epson salt is all that is needed with it. I got the bloom and finish line to go with the Jacks for Tap as well and so far so good. It’s easier to dissolve as well .
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