COCO COIR Stunted Growth, Mystery issue, Help Appreciated

[HighFlyer]

Hi to all, and thank you for reading this post and hopefully contributing your experience based knowledge for how to get past this issue in the garden. These are varieties of Kush's, all from seed, all varieties have same issues so I don't think its the variety. They are stunted, top stem and new branch nodes have lame new growth, no vigor.



POSTED FEB 4- coco and rock wool same issues - top drip recirculating hydro - ph 5.8 - 6.2.
- house and garden nutes, ppm x500 between 600-800ppm, with tap water very clean under 100ppm. -
most of the pictures, plants are 3-4 weeks old not including germinating ; so 3-4 weeks old in current media.
- a few of the plants are excelling (are older by 2-3 wks), the ones I've kept as mom's, and don't have stunted new growth.
- i've tried more calmag, raising lights higher (1000w MH), a day or two without lights (one of my theories is that these are in shock) - temps 70-84 - humid 25%-60% - water in res between 60-65.
- the roots are happy, rock wool has white roots out the bottom, and coco has root tips out smart pots
- sprayed/misted with calmag water and rhizotonic to treat problem if it is shock, slightly better but not much.
- at this stage typically veg plants are taking off in hyperdrive, not stalled out like this.
- I've experienced both broad, cyclamen mites and root aphids and i'm pretty sure not the issue here as haven't had those suckers in years, these came from seed, and nothing to be seen under microscope.

UPDATED: 2/13
I thought maybe I was over watering or over feeding. So I cut back on waterings for a week and used diluted nutrient solution.
Here's the update, after a week of limited hand waterings and watering with diluted nute solution, around 300ppm.

1. no more automated waterings. I waited till the media (coco or rockwool) was just about dried out and plant beginning to flag before watering
2. some plants in veg are excelling and either haven't got the problem yet or skipped over it - and are doing fine. some still have the new growth stunted (picture #4) - the effected plants are growing a bit taller, and new branches are forming, but its all stunted.
3. could the problem be pythium or aerobic bacteria? I'm about to water in the flower room (pictures 1-3) with Actinovate to try to knock out any fungus or bad bacteria. I'm also brewing compost beneficial tea to use in 48 hours.


UPDATED 2/15
- I, along with many others I have consulted with, are at a loss as to the issue. Anybody who has seen this before and defeated it, or has any detailed help to give, I appreciate it!

[Waltermelon]

What does your fan situation look like? Wind stress?

[HighFlyer]

Fan situation is normal,1-2 fans blowing over top of the canopy. The fan situation hasn't changed - I was getting average to above average results with the same fan situation before this problem arose.

[Mr.furley]

What's the nitrogen situation?

[HighFlyer]

The nitrogen situation is steady. Nitrogen from house and garden aqua flakes a&b, with some zen additive, res changed out 1x week.

[Mr.furley]

Are you leaf dark green?

[UrbZ]

They do look awful dark to me. I would lean toward nitrogen toxicity as well imo.

[HighFlyer]

Lockout has been considered - I flushed the media last week with diluted nutrient solution and h202, let the media dry out, hand flushed again, now the media is holding just 500ppm, which is well below the normal 700-900ppm that is usual for this stage for these plants. Now I've returned to regular daily or every other day waterings with 600-700ppm (5.8ph). Still the stunting persists. Whatever is happening in the main stem at the point of new growth isn't letting go, isn't breaking free to allow vigorous new growth.

[Waltermelon]

Have you thought about changing nutes temporarily? I know h&g are supposed to be some of the best. But even Rolls Royce has flaws that make it to the final costumer.

[HighFlyer]

Yes, I have. in the old days of single strain cropping, I was faithful GH man. I've brought it back to do side by side tests. I've started running it now in veg; 1 pt micro - 2 pts veg. looks about the same

[Mr.furley]

Very good point W.M. I would be curious and if you check your runoff pH and by chance have you PPM your runoff

[HighFlyer]

Hi, Yes, I have a small cup that catches runoff from the tray before it drips back into the res. The runoff pH is between 5.6-6.4, and PPM runoff was high after I hand watered and flushed a week ago, but now it is at 700ppm, just 100ppm above the res.

[Mr.furley]

HighFlyer,
Thank you for being so patient and thorough with your answers. It sound to me that you have a good knowledge of cannabis growing under your belt and have tried a lot of deductive reasoning.
can I ask are you watering to runoff every couple of days? Do you let your pots dry out completely? Pot size? What is your practice for spraying the foilage with Cal Mag, time in light cycle, how often? Do you feed nutes every watering? When you say the ppm was high, how high? No pun intended. We really appreciate your detailed descriptions and responses it helps tremendously with diagnosing a problem.
I have a couple suggestions but would like to know a little more first.

[HighFlyer]

Hi Mr. Furley, thank you for the kind words and I appreciate your effort!

1. As of Feb 4 I stopped watering on automated basis (in the past I've used rockwool and automated watering worked well). this is my first run with coco in 1 gal smart pots. before Feb 4 yes I was watering to run off at least 1x / day. I know now for coco this is too much. after feb 4th I've been watering to runoff once the media dries out, but before leaves begin to flag.
2. pre feb 4 i tried spraying with cal mag 1x every two days, to try to loosen up or get that stunted new growth to unfold. it didn't help.
3. currently these flower plants are at the end of wk 2 flower. prior they were in veg for 18 hours/day 1000w MH. top drip watering system in flower. ebb and flow in veg.
4. as far as nutes every watering - i'll flush and make a new res 1x / wk. i'll bring ppm up to say 900 and once the res drops to about 600 (fresh water auto refill) I'll add nutes and bring the res back up to 900, as long as the runoff is not more than 150ppm higher than the res ppm. so no i don't add nutes at every watering. i'd say over the week on average i'll re-up the res with nutes twice.
5. when i was letting the media dry out last week for the first time, and then flushed, the ppm runoff was up at 1300 (i was flushing with about 300ppm nutes diluted water). since then i've thoroughly flushed the media and got it down to 400ppm. week 2 flower i'd normally be watering up at 1000, and the plant happy without burnt tips. with this stressed condition i'm running res at 700ppm, 5.8-6.2

I look forward to your suggestions!

[Waltermelon]

Wait, you're in 1gal smart pots with those?

[PRIMO]

HF HI. I have never grown in coco ,just a dirt farmer. If they were mine just to eliminate one possibility I would prep a five gal. S.P. and to be as gentle as I could, I'd cut away the one gal and repot and water to runoff with pH'ed cal-mag/water. Then stare at it and think positive. Maybe.

[HighFlyer]

yes, 1 gal smart pots with straight canna coco

[Mr.furley]

HighFlyer,
Thanks for your response and as my signature says
"I like to help doesn't mean I'm qualified"
I do grow in Coco and my practice does slightly very from yours. I would like to touch on my lack of experience with topwater feeding and Dwc before we start, I have none to speak of. Like I said I'm a coco grower that hand waters.

1). For me it is super important to let my pots dry out with the "lift the pot" system to determine a watering schedule. Once you start picking your pots up dry and after watering you'll get the hang of how that works, and going by weight of pot seems to give a better indicator of watering times then Leaf flagging. it works out for me to water every 3-5 days with 1.2 to 1.5 gals on average to more depending on being a feed/flush Into a 5 gal smart pot depending on plant stage (of course) and if it's a feed or water/flush my runoff will be a small Trickle @ feeding up to a gallon or more during water flush. This practice is a Fail-Safe method for growing in Coco and in my opinion the best one to go by when growing in coco for the first time.
It has always dumbfounded me as to how a plants roots can live in Hydro submerged in water yet develop problems when the Coco is kept saturated all the time, but for us who water to run off this holds true and over watering is a big problem! It's just to much water and a lack of available oxygen to the roots ( you can't aerate Coco, or can you).
with that said I do have a General understand of how many peeps grow in Coco, water/feed 1x, 2x, and more a day/week. it is small precise doses of nutrients and/or water pre-measured to exact amounts through practice and patience with little to no runoff. which brings up my first suggestion.

Patience! I think you have been overwatering and it will take a bit for the plant to recover, but I also think you may have a root problem and I'm lean towards rootbound (from your pictures your roots look healthy but the pots look small), it will stunt your grow and throw you all kinds of of leaf symptoms. My rule of thumb is circumference of plant should not be much larger than circumference of pot! especially growing in a 1 gallon.
I know it is possible but it's not practical for a healthy plant unless you are on a short short veg cycle or something like 12/12 from seed or sea of green. From my understanding most who top water feed or daily feed do not water to run off but I have no basis on if I'm right right or wrong about this subject due to lack of experience with it.

2) I do not foilage feed anything to my plants except for a case of bug infestation or fungus after they are out of the humidity Dome unless I'm spraying water to contain pollen during removal of nanners. But that's just me.

3) did you transplant from Hydro? (ebb n flow right?) To coco? If I'm understanding this correctly this could be part of the problem although it sounds like they've been living in their new home for a while transplant shock can look like overwatering.... ect ect. I would highly discouraged erratic light cycles like turning it off for a couple days. But encourage raising and lowering to eliminate heat/light problem.

4) It sounds like your ppm is in proper range, I have gotten "a little high" before at 3000ppm+ from peeps. Yours is hitting and should be eliminated as a problem. in my experience if you can get your PPM down close on your run off to your pH water number going in, you have flushed completely. Although I do find it is never the same even after two weeks of flushing but close.
I do Like Waltermelon suggestion about the nutes. My first intuition said you had nitrogen toxicity. I would not rule that out but once again patience will play a key factor in seeing if that's your problem,. If its is, a flush and dry out will fix that over time.

You have eliminated the majority of commmon problems from the known signs of your symptoms (light, heat, wind, genetic, bugs)
but I think a few still persist, pots size/root problem, overwatering, and/or nitrogen toxicity are all a possibility with what I can see.
I hope this helps narrow down this problem for you. Please feel free to call me batshit crazy if i am but do Keeps us posted and good luck.
Mr.F

[HighFlyer]

Hi,

1. lift pot for sure is the way to go. I have sooooo many girls that lifting everything like that is too much. I should probably go back to rock wool. I know a dude who has a dozen or so in coco and hand waters with the lift method and he's stoked on it. lift method for me isn't practical.
2. my roots don't sit in water, i'm not dwc. i'm top feed recirculating. there is a res under the tray, the pump turns on and the drip lines water the plants. the runoff goes back to the res.
3. this is what no one told me about growing in coco, that its just like growing in soil that you have to let it dry/air out before watering again, which doesn't work for me. i like to run an automated watering setup, in 6" rock wool cubes, once they're big enough, water 1x / day to runoff, and if at the end of the light cycle they're light, i add a watering 4 hours before the lights turn off.
4. yes i think overfeeding was a problem for about a week in coco. but i stopped and its not recovering. perhaps the damage has been done and that's it. But I don't think there's a root problem - check out the picture I posted earlier where I dissected the root ball of one of my most suffering girls. the roots are white and strong.
5. pots size/root problem, overwatering, and/or nitrogen toxicity

I have autos in a different room that are going nuts, should be a bumper, in coco 1 gal pots, and some are like 2-3' wide, and 4' tall. even growing in rockwool 6" cubes i've had huge plants. probably better to be in larger media but I don't find its a big hinderance. overwatering - i dealt with that. nitrogen toxicity - I've heard this one... and it could be the issue. but with all the flushing i've done and lowered ppm to 300 (back in feb 5) wouldn't the issue have gone away? and nitrogen toxicity pictures show burning and yellowing on leaf tips.

definitely not bat shit crazy - i really appreciate your help! I'm trying to figure this thing out, and what i'm doing isn't working, so I'm looking for new ideas!

[Campesino]

Do you have any perlite mixed in. What else, or just Coco? In pictures it looks like might be pure coco...
I grow in 50/50 coco/perlite and water daily to run-off. You need to have perlite to retain sufficient O2. With pure coco you can drown your roots, but it is impossible to over-water 50/50 coco/perlite

[HighFlyer]

Hi, you're right I have pure Canna Coco. is it possible to use perlite and have a recycling reservoir? do you think the roots look drowned/damaged in the picture of my original post?

[Campesino]

Tough to say by looks of that pic, but Coco is not ideal on its own. Water and o2 retention properties are improved by mixing with Perlite.
I am not sure what the issue would be with the recycling reservoir... I drain to waste. People that I have seen with such systems certainly use perlite in their coco. Are you worried about the pumps?