A discussion about Jacks 321 and additives

What are some of the additives that are most advantageous to add to jacks? I have seen people adding things like silica, hydroguard, MPK and micronutrients. How important are these additives and how much of a improvement do they really make? Additionally, what are some other additives you guys and gals commonly use with jacks?


I switched it up from time to time but i Usually do something like this once a week when I have some going. Occasionally use silica.


People that use silica are going to use it with any line of base nutrients, not just jacks. Potassium silicate isn’t stable with other elements in long term mixture so it’s generally in addition to your base package.

This is pretty common to hydroponic grows, although not limited to them. It’s more for conditioning nutrient solution and protecting root mass than anything else.

There is already mkp in hydroponic blend/part b. Those who add this are trying specifically to change the final npk ratio of the solution. Most here that you see using are changing to more like lucas formula and only doing so for portion of the grow.

Do you mean microbials? You will see a lot of tribus, fishshit, recharge, great white, etc because jacks is synthetic and doesn’t contain any. But micronutrients like Iron, Boron, manganese aren’t added by anyone I know of unless subtracting significantly from standard ratio. You shouldn’t need any of these as they are covered in base package.

If you have a decent understanding of chemistry and can look at plants and determine how to make them better, you can probably justify having a lot of stuff. But for most the 3 part is capable of doing just about anything that’s needed. Plants will grow healthy without the silica, but it’s pretty cheap and does have some benefits.

Personally, I feel MAP and Potassium Sulfate give you way more flexibility than MKP, but there’s also no major influencers making youtube videos on how best to use it, so very few do. Very few people understand how to use Potassium silicate too, but most can tell you what their nutrient manufacturer recommends, and that’s good enough to keep you rolling most of the time.


What is the best type if silica to use? I have heard several kinds being thrown around. Silicon Dioxide and potassium silicate, the most common ones. Monosilicic acid, which is “supposed” to be the easiest for plants to absorb because the chemical conversion usually done by microbes and the plants is already done and then there’s silicon, which is a purer, un oxidized form of silica dioxide. Also silicon is an element where silicon is a chemical compound.

I think @Graysin is playing with adding micronutrients into the mix.



I believe the information you have on different types of silica is correct. Although I’m not really sure it matters a bunch either. I use potassium silicate and it will do everything you need it to. I actually use opposite of how just about everyone will tell you to use it, and it still works. Plants aren’t going to need a bunch of silica so I don’t see any reason to make sure you have it in super available form, but if you had to buy anyway would be a decent reason to get one over another.

I’m not sure what the conditions in which Graysin would be using, but im guessing fine tuning and tweaking other things in recipe too if a most or stem product is actually needed. They are certainly available, but not something I would tell average user they should have without good reason.

I think it’s more important to make sure whatever you have is being used properly than anything else. A great nutrient package can be attached to sickly looking plants by way of something as simple as a vpd or temperature issue. A very modest nutrient package can look great in the hands of someone that has a really good feel for identifying and correcting issues. And there’s no magic bottle that will double your production.


Potassium silicate is “best” generally. Monosilicic acid is best for ready absorption. I’m using MSA now. I’m not far enough along in an MSA grow vs a potassium silicate grow to have meaningful results between the two. more importantly, I wouldn’t be doing a side by side grow comparison so it wouldn’t be conclusive anyhow.

I’m largely adding micronutrients to supplement where I f**ked up. I let my pH drift so far out of whack that I had to get myself off cycle and add in micro nutes at the appropriate pH to allow re-uptake. Interestingly enough, I screwed the pooch pretty hard trying to resolve that.

This was that plant about 24 hours after flushing and treating with a micronutrient blend. I’m not sure it made her worse, but not better (yet). I’m afraid to look, consequently I haven’t been in my grow room yet.

To Dbrn’s point, most good cannabis friendly fertilizer will contain the micros needed. I just happened to really goof up.


I couldn’t agree with you more on this one. I know there are a lot of newer growers here that may not know very much about some of these additives seen being used and talked about here so I figured it why not start a thread to have a place to discuss any additives and get some facts and some opinions on them from experienced growers.


She dont look too happy :flushed:

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Not at all. Let that be a critical demonstration of why proper pH matters.

I added the MSA into my nutrient schedule but was so accustomed to adjusting pH based on my normal Jack’s routine, I didn’t think or bother to check the pH after adding MSA into the schedule. Consequently, everything in the room got pH 7-8 range feedings regularly for about 2 weeks. She was my canary in the coal mine, the sensitive one in the bunch that clued me in to something being wrong.

So when I went back to basics, I realized I locked her out of any meaningful micronutrients.


She stopped drinking entirely. I’m hoping she’ll bounce back now that the problem is addressed, but frankly even if she isn’t, I’ve learned something valuable.


I felt bad hitting :heart:. Pushed more on impulse. What we really need sometimes is a feel for ya button.:vulcan_salute:


For my grows in coco I only add silica and microbes. In my aeroponic set up I add silica and Southern Ag (root inoculant) less is more in my opinion :love_you_gesture:


Same here. Last grow in fact I only added microbes. I find the plants are quite stout using Jacks and silica is unnecessary for that. Probably would help the plant be more resistant to environmental issues if I used it more regularly. I have the grow down to a minimum of work at this point and dont see the need to add anything. I am not even sure the microbes are doing anything at all.


This is my Jack’s TAP feed schedule during the main weeks of the grow. All quantities are per liter. Dry nutrients are grams. Liquid in ML.

Before I switched to Jacks and coco I used Advanced Nutrients. I continue to add many of of AN supplements I like.


Beneficial microbes(Tribus), kelp, and molasses is what I use in addition to jacks. As dbrn stated, it’s a synthetic nutrients don’t have the microbes, so you have to get them established.


Great info and insight in this thread…
I’m using jacks in coco with ro water. I add about 2ml/gallon silica to my mix and it brings the ph in perfect every time. If I don’t add the silica I have to bring the ph down quite a bit.
I’m still learning but I will say that the silica stiffens the crap outta the stems and branches to the point where training can be difficult without snapping plant parts :laughing:


Silica is also necessary as trichome stalks are composed primarily of silica. So definitely beneficial to your grow. Be sure to always add first or mix separately and add (this is what @dbrn32 does to manage PH).

I run MKP from the flip for 3 weeks with a modified 2-2-2 Jack’s, then resume normal 3-2-1 program. It is supposed to add a ‘bump’ of P and K right when plant is starting to need it.


I have been seeing the MPK more and more but Do you really need the MPK with the modified jacks ratio?

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I agree they will. I add silica blast at times with extremely large flower producers. Helps flower growth and trich formation. Also reputed to help high temps and fluctuations in environment. I HAVE noticed a difference but I am in living soil and do not add anything else but a RARE calmag foliar. Mag is a nutrient i do add during cook. Reused soil always seems light on it. A little…little is key…molasses to feed the biosphere not the plant.


Depends on which modified ratio. To go 2/2/2/1.2 removing mkp would change final npk ratio. If you want to run different npk then would need use different mixture ratio.

What you’re seeing here is a large group of people just going it because a small group of people said they have had success with it. I’m not attempting to throw shade at anyone, but most couldn’t tell you anything about this other than what greengene’s garden has put out about it. And there’s nothing wrong with that, but there probably isn’t a large group of people here prepared to discuss anything more than that.

When you get to mixing this stuff, any change in recipe or adding/subtracting of different elements or compounds is going to change the final npk ratio. So if you want to run modified jacks to roughly 1-1-2 npk you would need to follow the recipe as listed. That doesn’t mean you couldn’t just run 2/2/2 and no mkp, just that the final solution would have different npk ratio. Make sense? If so, you can download hydro buddy and plug in numbers to see.