Jacks 321 with autos

I'm asking for any opinions please on what strength to use for autos in RDWC. After having just converted from DWC to RDWC, with good results so far, I'm feeling adventurous and want to try changing the nutes too.

I'm using the Botanicare line in my current grow. These plants are doing well with an EC running between 0.9 to 1.2 in RO. Would this be a good strength with Jacks 321 or should I start lower and work up from there?

Also, is it a bad idea to change over to different nutes in the middle of a grow?

Tricky question... you open yourself up to inforseen variables/imbalances switching products mid grow?

I'd assume 'Grow' A&B would be designed to work with 'bloom' A&B from the same product line...

I guess you could compare the NPK levels, and levels of micro nutrients but it could become quite complicated quite quickly to figure out whats wrong if you run into issues.

Personally, if things are going well, I think id 'err on the side of caution' rather than rock the boat by using a new product half way through.

futurebanjo said:

Tricky question... you open yourself up to inforseen variables/imbalances switching products mid grow?

I'd assume 'Grow' A&B would be designed to work with 'bloom' A&B from the same product line...

I guess you could compare the NPK levels, and levels of micro nutrients but it could become quite complicated quite quickly to figure out whats wrong if you run into issues.

Personally, if things are going well, I think id 'err on the side of caution' rather than rock the boat by using a new product half way through.

Click to expand...

That's what I've been wondering about too. I've got an angel on my left shoulder saying better not and a devil on my right telling me to go for it,

I don't see any issues switching nutrient mid grow. You are growing in a solution of salt ions, doesn't matter who puts them in a bag or bottle.

I am switching to some sort of dry nutrient like that as well, but not mid grow, especially mid flower Plus I want to use what I already own.

A bag of Jacks is almost 100 usd on amazon, it would feed so much more than 100 worth of liquid nutrients.

Maybe some day I'll get all the organic soil amendments guys talk about to stop spinning my head and learn to just use water....
That stuff seems way complicated.

marzig said:

I'm asking for any opinions please on what strength to use for autos in RDWC. After having just converted from DWC to RDWC, with good results so far, I'm feeling adventurous and want to try changing the nutes too.

I'm using the Botanicare line in my current grow. These plants are doing well with an EC running between 0.9 to 1.2 in RO. Would this be a good strength with Jacks 321 or should I start lower and work up from there?

Also, is it a bad idea to change over to different nutes in the middle of a grow?

Click to expand...

Chemicals is chemicals. The plant doesn't know if the chemicals came from bottles with pretty labels or a sack of dry ferts. The nutrient mix should be very similar from one line to another but the biggest reason to be able to switch is that plants function in a range of chemicals and, since the chemical mix in the res changes on an ongoing basis, unless you pump in something that's out of range, it's no difference to a plant.

I used Botanicare for my first few grows and switched to Jack's 3-2-1 for RO when one of the Botanical ferts wasn't available because of a government edict here in the People's Republic of California. I had the same concerns but someone stepped me through the process and I haven't looked back.

For EC, I start at 0.6, jump to 1.0 in veg, max out at 1.5 or so in flower, and then back down and I run Part A + Part B + Epsom from drop to chop. I did try their "bloom" fert for this last grow. Never again. pH plummeted for the first week or so of flower and then I found the article on scienceinhydroponics.com that explained why "bloom boosters" are of little value overall and of, essentially, no value at all in hydro. Lesson learned.

[time passes]

Ugh. can't find the article.

[time passes]

Google to the rescue.

This is the page I was looking for. The author is a PhD chemist and the author of HydroBuddy so he's got a pretty good understanding of how hydro works. One dalliance with a bloom booster was enough.

Handy Tip
Great info on that site but the search function isn't that good but I found it using Google's "site search" function.

Enter "site: " and then the URL of the site, then a space, then the search term.

To find that article, I entered this string into Google - site:https://scienceinhydroponics.com/ bloom

I had similar questions to you when I started growing and a chemistry jock (on another site) PM'd me about pretty much the same questions you're asking.

Why does pH change. It's all about what nutrients the plant is taking up. The rule of electro equivalence states that the ionic charge of the nutrient mix has to stay in balance. This graphic gives some of the details.




I've attached a couple of documents re. res management that I've found helpful. The Bugbee paper exposed me to the concept of "nutrient balance" and helped me understand why EC is, well, not a "myth" but it's more like "dead reckoning" than using a GPS. scienceinhydroponics.com has a lot of good info on that topic, too.

I hate to bring it up...but after growing many autos...
Jacks with Photos are where its at.

If you want to yield and all.. I had to Mephistos that did not trigger until first week in August...lets call them photos.
BEST YIELD EVER on an auto.

After many grows, unless you are stuck with outside conditions they pale.

gwheels said:

I hate to bring it up...but after growing many autos...
Jacks with Photos are where its at.

If you want to yield and all.. I had to Mephistos that did not trigger until first week in August...lets call them photos.
BEST YIELD EVER on an auto.

After many grows, unless you are stuck with outside conditions they pale.

Click to expand...

I've been reading about that since soon after I started growing in 2021. I haven't been able to grow small plants, auto or photo.

Both types have generated yields of >700 gm/sq meter. I stopped growing autos because I can't control the size but, in terms of yield, I've had zero issues.

Granted, I do feed my plants well. With autos, I run DLI's in the 80's but, with photos, can only get to about 42mols.

First two photos are autos.




Photoperiod - veg light + flower light, topped, and LST'd.



Gelato autos, running amok. There's one plant hiding on the left side. Pretty much all off the visible plant material is one Gelato auto with a Growcraft flower light in the tent + a Vipar XS-1500 for the front row.

Delps8 said:

I've been reading about that since soon after I started growing in 2021. I haven't been able to grow small plants, auto or photo.

Both types have generated yields of >700 gm/sq meter. I stopped growing autos because I can't control the size but, in terms of yield, I've had zero issues.

Granted, I do feed my plants well. With autos, I run DLI's in the 80's but, with photos, can only get to about 42mols.

First two photos are autos.




Photoperiod - veg light + flower light, topped, and LST'd.



Gelato autos, running amok. There's one plant hiding on the left side. Pretty much all off the visible plant material is one Gelato auto with a Growcraft flower light in the tent + a Vipar XS-1500 for the front row.

Click to expand...

Sorry to ask a question not concerning this thread, but when people say things like 700 gm/sq meter, do they mean fresh weight trimmed, or dry/cured weight, as that can be a huge difference!

futurebanjo said:

Sorry to ask a question not concerning this thread, but when people say things like 700 gm/sq meter, do they mean fresh weight trimmed, or dry/cured weight, as that can be a huge difference!

Click to expand...

Dried flower.

Westmoreland gives yield estimate based on mols of light over the life of the plant. That's the modern version of yield esitamators that used wattage of the HPS bulb. Those are very old school so I never used them.

The yield estimate is right up front, in the Abstract.

Interesting title, eh?

This paper was one of the main reasons I went with separate veg and flower grow lights. I bought Growcraft lights but they switched to white LED's (and are out of business) so it's only HLG that makes separate veg and flower LED's.

Hmm, I haven't read that paper in some time, probably since 2022 but, now that I read it again, it really is just chock full of good stuff. In fact, a lot of what's in that paper is in Westmoreland's You Tube videos that the did this Spring. In those vids, he shared some of the research that he presented for his PhD thesis - he's studying under Bugbee. And, it just so happens that he's the lead author on that paper.

I checked out the attached paper "Principles of Nutrient and Water Management for Indoor Agriculture Principles of Nutrient and Water Management for Indoor Agriculture " which has been gathering dust in my laptop.

If you scroll down to Action 3.1, you'll see that text I've highlighted some text in this body of text:

"NH4+ uptake releases protons, which lowers the pH. It is possible to stabilize pH by controlling the concentration of these two ions in solution (Figure 3), but NH4+ is taken up 100 to 1000 times faster than NO3− [56], and an elevated concentration of NH4+ thus causes a rapid pH decrease [57]."

Key words "rapid pH decrease".

I had thought that it was K/P being taken up that threw my res into a tailspin but this paper makes me reconsider that. When I head over to my handy dandy Nutrient Profile Calculator spreadsheet, I see that Jacks has no NH4.





But, per the ingredients list on the back of Jack's Bloom Booster, I discover that 50% of the N in that product is Ammoniacal Nitrogen. 50% is a lot more than 0%, if I'm not mistaken, and, perhaps, that's enough to be considered an "elevated concentration of NH4+ [which] thus causes a rapid pH decrease."

I swapped nutes out yesterday morning with Jacks and the plants haven't missed a beat. 50% concentration got the EC right in my target area at 1.1
PH was just a little low at 5.6, adjusted it to 5.8 and it hasn't budged in 36 hours.

I can't believe how little it took to mix up 20 gals.