HELP! D39. My 5th growth in row is failing. (1st with autopots) Yellowing TOP leaves. PH, zinc,iron, something else?

[BipolarBear91]

I posted the same topic in "autopot" section ,but it is a small one.. If I am breaking rules, my apologies, I will delete the post in "watering systems" subforum.


Hi! Skip the first paragraphs if you dont wish to read my sorrow story I would appreciate any input....

The hobby I hoped would be a stress reliever has been a stress generator and I am probably giving up after next grow.

I have tried EVERYTHING and honestly, at this point, I could be convinced that we live in a simulation and someone up there is laughing at my failures lol. Because 15/16 dead/impotent plants during last 12 months just seems ridiculous, when I have tried different soils, nutes, phs, ppms, and even different watering techniques and DLI schedules.I wont go too deep into details but my last 4 grows (each 4 plants) were failures (From 16 plants only 1 produced below average product). All had the same characteristics - deficiencies from day 20 that led to most fan leaves falling off by day 40 .. Flushing didnt help. Some plants finished, but the smoke was very very weak.


But - THAT IS THE PAST. I BOUGHT AN AUTOPOT and maybe this time the grow be be good? WRONG

Yellowing from TOP leaves and weird yellow patches on top leaves.

Setup:
47litr reservoir,1 plant, 15litre plastic pot, 100 % coco, no airdome, no airbase.
1 autoflower - SODK (mephisto) - 39 days old from seed
Mars ts 1000 + kingbrite 240w = total 390 watts
Tent: 5x5x7
Temps:25-27
Humidity: About 60%
DLI : 35-37 (was lower for seedlings and early veg)


FEEDING: Canna coco (a,b, cannazym,calmag) Tap water (300ppm) + RO water. 80% RO and 20% tapwater, making it 50ppm or 0.1 ec. Then I add 150 ppm CALMAG to get to 0.4ec of 200 ppm.

First 23 days handwater with 6ph and CANNA COCO "light nude schedule" (meant for autoflowers)
Day 23: 12 LITRES of 500 ppm 5.65ph reservoir fill
Day 23-day 30: Reservoir never went above 5.95ph and TRAY never weent above 6.1ph
day 30-day 37: 15 litres of 700 pm 5.7 ph water (Got LIGHT nute burn in tips)
day 37 - day xxx: 15 litres of 700 ppm (1.4ec) 5.7 water. Didnt increae EC due to nute burn last time.

Photos are from today - day 39. I noticed first yellowing/patches on day 35. It has gotten much worse since then. There were 4 patchy/yellow top leaves 4 days ago, now almost all of top canopy has weird discoloration.
My theory.

1. Micronutrient deficiency (problems start from TOP) - zinc or iron.
   why? Maybe because not enough zinc or iron in my 50 ppm solution. (80% ro + 20% tap) I dont think Canna coco has zinc or iron in their nutes.

If this is true, then why the WEIRD yellow patches? Zin/iron is not the only thing going on.
2) PH LOCKOUT
But why and how? If ph never went above 6.1 in tray
CONCLUSION: I will refill the reservoir tomorrow. I dont know what do do.
Any help appreciated.

 

[TheFerret]

I think you may be on to something with the zinc/iron

How to fix Cannabis Zinc Deficiency (Z) Pics & Symptoms

Problem: A cannabis zinc deficiency causes younger leaves to start yellowing in between the veins. Leaf tips get discolored and may start dying.

www.growweedeasy.com

How to fix Cannabis Iron Deficiency (Fe) Pics & Symptoms

Problem: A cannabis iron deficiency causes bright yellow leaves on new growth. This deficiency is usually caused by problems with pH.

www.growweedeasy.com

hopefully someone with experience with those nutes could chime in

 

[BipolarBear91]

I think you may be on to something with the zinc/iron

How to fix Cannabis Zinc Deficiency (Z) Pics & Symptoms

Problem: A cannabis zinc deficiency causes younger leaves to start yellowing in between the veins. Leaf tips get discolored and may start dying.

www.growweedeasy.com

How to fix Cannabis Iron Deficiency (Fe) Pics & Symptoms

Problem: A cannabis iron deficiency causes bright yellow leaves on new growth. This deficiency is usually caused by problems with pH.

www.growweedeasy.com

hopefully someone with experience with those nutes could chime in

Hmm..


The thing is- zinc and iron get locked out if ph goes too high. I dont find this plausible because I tested ph regularly and max was 6.1. Of course, root zone as higher than 6.1 (tray water PH), but high enough to cause lockout?

So this is what baffles me. If my tray water ph was normal, then zinc deficiency can only be caused by actually not getting enough zinc. Mayb my 50 ppm TAP water wasnt enough to satisfy zinc/iron needs... dunno

@Mañ'O'Green - I preemtively apologize for tagging you. I know you probably get tagged all the time, but hey, I got nothing to lose and I am desperate. And you are the "man". I have a lot of your texts and advice saved

If you know someone else in this forum who might help, can you tag them please?

Thank you.

 

[AdirondackGreen]

Hey @BipolarBear91 , I've been using autopots for a few years, half a dozen runs now. And some general thoughts based on your details and that experience.

My guess, Potassium Toxicity.

1. Vendors matter, pick ones you know you can trust
2. trust their feed charts
3. trust their advice.
   

So given your comments:

• COCO: 100% coco is uncommon, . autopot themselves suggest ~30% #3 perlite in coco to allow get right oxygen/water level around roots.
  • Rinse, Buffer, Balance. - where is your coco from? Is it high quality washed and buffered? Coco cation exchange capacity is no joke. Excess salts from cheap vendors or lackluster buffering can give potassium toxicity or sodium buildup.
• PH: (I agree with you ph seems unlikely). Coco does not have all the "helpers" of life like soil. It's inert and leaves all the work to the plant. For chemical process to work in coco 5.5-6.5, BUT my experience says they do better 5.9-6.2 , many feed vendors will advise similar.
• EC/PPM: Those numbers sound low, but as long as ratios are good would just be slower growth, anyway, Canna Coco (dont use) says you PPM should be around 800 by week 4, I've had great luck with GenHydro and their up to 800-1000ppm by week 4.
• CalMag: I dont recall what the measure does off hand, but I use ~2ml/gallon during veg and bloom.
  
  
  The Bible --> https://www.cocoforcannabis.com/toc/ (also on kindle)

some of my experience -> https://community.adirondack.green/blog/35-cannabis-in-coco-coir-optionally-organic

 

[BipolarBear91]

Hey @BipolarBear91 , I've been using autopots for a few years, half a dozen runs now. And some general thoughts based on your details and that experience.

My guess, Potassium Toxicity.

1. Vendors matter, pick ones you know you can trust
2. trust their feed charts
3. trust their advice.

So given your comments:

• COCO: 100% coco is uncommon, . autopot themselves suggest ~30% #3 perlite in coco to allow get right oxygen/water level around roots.
  • Rinse, Buffer, Balance. - where is your coco from? Is it high quality washed and buffered? Coco cation exchange capacity is no joke. Excess salts from cheap vendors or lackluster buffering can give potassium toxicity or sodium buildup.
• PH: (I agree with you ph seems unlikely). Coco does not have all the "helpers" of life like soil. It's inert and leaves all the work to the plant. For chemical process to work in coco 5.5-6.5, BUT my experience says they do better 5.9-6.2 , many feed vendors will advise similar.
• EC/PPM: Those numbers sound low, but as long as ratios are good would just be slower growth, anyway, Canna Coco (dont use) says you PPM should be around 800 by week 4, I've had great luck with GenHydro and their up to 800-1000ppm by week 4.
• CalMag: I dont recall what the measure does off hand, but I use ~2ml/gallon during veg and bloom.
  
  
  The Bible --> https://www.cocoforcannabis.com/toc/ (also on kindle)

some of my experience -> https://community.adirondack.green/blog/35-cannabis-in-coco-coir-optionally-organic

Thanks for reply.
1) Canna coco pre buffered, good bquality. Also Canna COCO nutes - havent heard bad about them.
2) I cant find it now but some very knowledgeable members from autopot reddit say to use100% coco and NOT use pebbles at bottom. I hav saved the comments about why that is better than default, but cant find them now.
3) I chose to feed a little less on purpose. But still got nute burn at 700 ppm (hanna scale aka 1.4ec), though small.


Can I ask why you think Potassium? Anything besides visual info from pictures? Some leaves look100% zinc, some have a shade of iron def (yellowing starts from stems). And others have yellow patches that I cant pinpoint.


P.S. ABOUT PERLITE - its not the comment I was looking for, but still..
"You don't need perlite in with coco when growing in autopots. It's important for a top watered grow in coir (for drainage reasons) but in a SIP system like an autopot -- perlite does not wick as well as coir. And as drainage is not a concern for a SIP system, perlite doesn't do anything to help; it only hinders"

 

[AdirondackGreen]

Can I ask why you think Potassium? Anything besides visual info from pictures? Some leaves look100% zinc, some have a shade of iron def (yellowing starts from stems). And others have yellow patches that I cant pinpoint.

For the reasons I shared above, coco will swap Cal&MAg for Sodium&Potassium, and the intervening yellow usually proceed the rust spots of potassium excess. But the leaves also look water laden.

I cant find it now but some very knowledgeable members from autopot reddit say to use100% coco and NOT use pebbles at bottom. I hav saved the comments about why that is better than default, but cant find them now.

As knowledgeable as the people who actually make the product? Also, I dont mean at the base, you need to mix it into the coco so it increases the porosity throughout the entire medium.

P.S. ABOUT PERLITE - its not the comment I was looking for, but still..
"You don't need perlite in with coco when growing in autopots. It's important for a top watered grow in coir (for drainage reasons) but in a SIP system like an autopot -- perlite does not wick as well as coir. And as drainage is not a concern for a SIP system, perlite doesn't do anything to help; it only hinders"

I dont who 'very knowledgeable members from autopot reddit' are ,but they are not from autopot -- thes ones who made the thing you're using. whoever said perlite cant wick properly is ignorant to science and facts, and I am including a few links belwo to that end, not from reddit.

Might be worth taking reddit advice at discount and start with the basics, from the manufacturer, that have been proven time and again, especially if you're struggling to get to win #1.

> Use quality substrates from reputable brands and ensure the mix is absorbent, light and fluffy.

AutoPot Growers Guides Potting Up - AutoPot Watering Systems USA

Growers Guides AutoPot Growers Guides Potting Up Also available to download and print! PDF DOWNLOAD

www.autopot-usa.com

> The ideal soil porosity in wicking beds would be at the higher end, ie around 60%. While it is often recommended that sand be added to soil in wicking beds, Perlite is an ideal medium for increasing porosity

https://www.waterups.com.au/what-is-perlite-and-why-is-it-useful-in-wicking-beds/

> perlite’s water-holding capacity are its miraculous ability to soak up moisture against the opposing force of gravity

https://www.perlite.org/wp-content/uploads/2019/06/Perlite-Water-Holding-Capacity.pdf

** PERLITE PROMOTES BETTER WICKING**

Also check this forum, various folks have experimented and perlite mix consistently yields bigger better results.

CD x CDLC 50/50 mix - 263g/9.5oz
CD x CDLC 100% coco - 183.2g/6.5oz
Total yield - 446.2g/16oz

 

[Del boy]

Hello i have done many grows with canna nutes and there coco which i still use they are good never got nutes dificeincies with them my advice would be to take it of the auto pot and flush your pot with your usual ppm of nutes with a ph of 6.1 until your run of is at 6.1 and your Ec is the same as you are putting in and top water for a few feeds and back off the cal/mag a bit its not necessary all through the grow

 

[BipolarBear91]

Hello i have done many grows with canna nutes and there coco which i still use they are good never got nutes dificeincies with them my advice would be to take it of the auto pot and flush your pot with your usual ppm of nutes with a ph of 6.1 until your run of is at 6.1 and your Ec is the same as you are putting in and top water for a few feeds and back off the cal/mag a bit its not necessary all through the grow

Thanks. Can I ask for 1 clarification?

Is there a consensus on how concentratd should the flushing water be for COCO?
You say "use you usual ppms" - that would be a flush with 700 ppm
I have heard "use the usual dosage" but I have also read to use 1/2or even 1/4 of your usual ppms to flush coco.


Is there even a difference?

P.S. DO you mix in perlite and/or hydroton?

 

[Del boy]

Thanks. Can I ask for 1 clarification?

Is there a consensus on how concentratd should the flushing water be for COCO?
You say "use you usual ppms" - that would be a flush with 700 ppm
I have heard "use the usual dosage" but I have also read to use 1/2or even 1/4 of your usual ppms to flush coco.


Is there even a difference?

Hello i never go that high with the ppms max i go with canna 500PPM else i got nute burn and but i allways just stick to the same EC when i have done a flush i dont grow in auto pots so rare that i need to do it. I think you get a bit more salt build up which will effect the ph around the root zone in the auto pots as they dont get flushed out when you feed like they do when you top water
These where grown with canna nutes at 500ppm feed twice a day

 

[BipolarBear91]

Hello i never go that high with the ppms max i go with canna 500PPM else i got nute burn and but i allways just stick to the same EC when i have done a flush i dont grow in auto pots so rare that i need to do it. I think you get a bit more salt build up which will effect the ph around the root zone in the auto pots as they dont get flushed out when you feed like they do when you top water
These where grown with canna nutes at 500ppm feed twice a day
View attachment 1567292

What was the yield, if thats not a secret?
I am at a point, where I dont want my plants to be big actually Due to humidity. I have good circulating fans, but am afraid of big cola rot (which I have had)
Tent is in my bedroom and I cant use a dehumidifier (loud)

That is why I currently grow 1 autopot and 1 biobizz light mix organic plant in a 5x5x7 tent


P.S. I am assuming you watered with 5% of pot volume in each of tice per day waterings?