Chem-Gro 4-20-39 from Hydro Gardens

plumbum said:

hey guys, wondering if anyone has experience running 4-20-39 Chen-gro with calnit and magnesium sulfate in coco?

I've started testing it and mix it the following way with RO water:

Pro-Silicate 1.5ml/G
4-20-39 1.8 g/G
MgSO4 1.8 g/G
CalNit 1.8g/G
Ful-Power 10ml/G
Hygrozyme 5ml/G


Nitrogen N Total 93
Phosphorus P 41
Potassium K 175
Magnesium Mg 48
Sulfur S 61
Calcium Ca 90
Iron Fe 1.94980
Boron B 0.95112
Manganese Mn 1.04624
Zinc Zn 0.23778
Molybdenum Mo 0.04756
Sodium Na 0.00000
Copper Cu 0.23778
Chlorine Cl 0.00000
Cobalt Co 0.00000
Silicon Si 19.5614
Selenium Se 0.00000

Total EC 1.5
ph 6.2

I am at beginning of week 2 in flower everything looks pretty good except I have some yellowing of the new growth. Not sure exactly what it is.

Is any coco experts here? Do you guys think that potassium level is too high to run in coco??

[URL=https://www.icmag.com/ic/picture.php?albumid=73709&pictureid=1757250&thumb=1]View Image[/url]

i've started infirmary thread and there is more information there if anybody is interested..

https://www.icmag.com/ic/showthread.php?t=343602

thank you for you help!

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plumbum said:

thank you Absolem, this is exactly advice i am looking for! i really appreciate it.

actually, before reading your post, i've started going similar direction raising N and Ca and keeping K/P the same

now based on your advice i will low K/P even more. my only concern is that my P will get lower then what i am used to. usually i run it around 80 and sometimes go higher with MKP spikes. but i keep K lower - around 140 ppm.

I am at the end of week 2. as far as i understand that you suggest to start running my previously written profile around that time. probably it makes sense to still drop Chem-Gro for few days to let more calcium get absorbed, what do you think?

here is what my numbers came to for transition time by lowering Chem-Gro and raising CalNit as you suggest, how does it look?

Pro-Silicate 1 ml/G
4-20-39 1.7 g/G
MgSO4 2 g/G
CalNit 2.7g/G

K - Ca = 24

N Total 129.2
P 39.2
K 159.4
Mg 53.4
S 68.2
Ca 135.5
Fe 1.84148
B 0.89828
Mn 0.98811
Zn 0.22457
Mo 0.04491
Na 0.00000
Cu 0.22457
Cl 0.00000
Co 0.00000
Si 13.04095
Se 0.00000

do you think P is too low now?

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Absolem said:

Hey Plumbum.

I think those numbers look fantastic for veg and up until day 14 of flower. I run my P in veg at 40 ppm and up it to 60 ppm day 15 of flower then up it again to 80 ppm on day 21 of flower. It helps keep the stretch down. I think the yellowing came from the high K slowing the uptake of Ca, Mg and N.

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mrrangz said:

ive been using this fert for about 3 months and end up with calcium issues around week3 and beyond. You have to modify the formula slightly.

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plumbum said:

Absolem, thanks again for your advices.

i have another question, if you don't mind.

when you are raising you P starting week 3 and week 4. what happens you your N/Ca and K?

do you always keep it relative to Ca levels? no more then 30 ppm higher?

what is the highest K level you think is safe to run in coco?

in Chem-Gro all P, K and micros are tide together. ultimately, i need to start mixing everything from scratch to have better control of elemental levels. but for now i was thinking to start using PeKacid 0-60-20 to bump P over K. it's slightly better then MKP, but quite acidic. i still need to figure out the way how to increase alkalinity without adding extra potassium to compensate.

i am also planning to add extra 1.5 ppm of Iron DTPA to bring total over 3 ppm

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plumbum said:

mrrangz, thank you for stopping by and sharing your experience and your charts. from your message i didn't really understand. do you get calcium issues following the chart you've posted? or that chart is actually works well for you?

what is your source water?

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Absolem said:

Hey Plumbum,

Great job mixing dry salts.
You got me. lol. I tell people to keep their K within 30 ppm of Ca and N during veg only. I've found running K 30 ppm higher in veg than Ca and N tends to cause issues from the coco not building enough of the cation exchange sites with Ca and Mg. I like to run my K, N, and Ca about the same during veg. About 130 ppm for N, Ca, and K during veg. For flower I drop my N and Ca on day 15 to about 100 ppm and up my P and K. I do this by lowering my dosage of stock solution A and then add more stock solution B to increase the K and P. Weeks 3-5 I up the P and K again by using a PK boost I make. On day 21 of flower the P levels hit a little over 80 ppm and the K levels hit about 200 ppm. When week 6 of flower starts I drop the PK boost. Which puts my P back down to 60 ppm and my K levels back to about 160 ppm.


Once my clones get roots and are transplanted they get 2/3's strength of the nutrient solution then by day 14 of transplant they get full strength feed. In coco your feeding the coco and in return the nutrient solution bound in the coco's cation sites will feed the plants. The plant feed is dependent how fast you can get the coco's cation sites fully charged. Here's a great read on coco.
https://hortamericas.blogspot.com/2015/07/buffering-coir-not-necessary-if-its.html

I had my substrate tested so I know exactly how many anions the cations will hold in the coco. I have a slick spread sheet that tells me everything about the fertilizer solution and how it reacts to the substrate if I change any nutrient dosage. It looks something like this but has much more to it. My nutrient profile is built for the medium I'm using. It's a mix of coco 60%, peat 20%, and perlite 20%. The nutrient numbers I've listed will work just as good in pure coco too. I do use RO water. Once I'm in the new building I'll build a nutrient profile with my water included.

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mrrangz said:

the chart is converted from chem grow feeding schedule (per 100 gallons). I just broke it down to make concentrates of each fert (chem4-20-39/calnit/magsulf)

and yes calcium deficiency symptoms appear with the feed recommendations provided by hydro gardens.

water source is R/O

I PH the water before adding them ferts. it does have a very stable ph.

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plumbum said:

thank you for clearing it up mrrangz. i was trying to follow their chart as well in the beginning, but started to have deficiency as well. my doesn't look like calcium though..

are you still running the 4-20-39 Chem-Gro, and if so what modifications did you end up doing. did it help?
also i would like to know what medium are you using?

i wounder if the problem mostly related to RO water? maybe CalNit and MgSO4 should be run much higher, especially with coco.

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plumbum said:

Absolem, i am just starting, but thank you. and thank you for your detailed explanation. it helps a lot. i am still seeing same deficiency. i will try to post a picture soon. i am trying to get closer to your recommended numbers and hopefully i would be able to fix it. if not, i would go back to Cutting Edge Solutions till i figure out how to mix my own raw salts.

Chem-Gro is a good mix, i just need to figure out how to be able to get potassium in the right place. i am concerned when i get CalNit high compared to Chem-Gro i would put my micros and phosphorus too low. of corse i could add some extra iron and MKP or PeKacid, but at this point might as well start from scratch.

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Absolem said:

Hey Plumbum.

I think you are doing a great job with the Chem Gro so far. You are so close to getting it correct. Your plants maybe a bit deficient in Ca but they are not that bad at all. The freedom of being able to manipulate any nute you want to get the desired ppm's is worth it. Plus the savings of using a salt based fertilizer is a huge advantage. I went through the same thing. Hang in there.

In regards to your micro numbers I run half the micro ppms you are. So don't worry about cutting back the Chem Gro. Looking at your plants they are just lacking some calcium. Calcium is not mobile in the plants so you won't see much change in the older leaves but should see the new growth looking greener.

Think of coco as one of those Pin Art games where you put your hand on it and it shows the indentation. Coco is the same. Right now most of your pins are pushed in with K and we want to change that to Ca and Mg. In coco unless you run through a couple gallons of solution feed through each pot it could take up to a week to see any change in the plants because you need to allow the cation exchange to build up in the coco.

I'm not sure where you are at in flowering or veg? If you are still in veg you have more then enough time to get the coir charged correctly. Keep running the numbers you posted in post number 5.

Cheers

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