Drooping Leaves on Autos - Please Help!!!

[HowardMarks]

Hey everyone, hoping you can help me out with a problem I have, first grow in over 10 years, things have gone reasonably well up until a few days ago and I'm going bananas figuring the problem out.

Problem
I have 2 auto strains growing, Royal Bluematic and Watermelon strains from RQS. The Watermelon's were drooping and initially I thought this was down to over watering, but appears I was under watering as I wasn't getting any run off. I now manually water each day, an hour after lights come on until I get 10-20% run off. But the problem now is persistent. The royal blfematics on the other hand have weird symptoms, one has lots of flower buds and stunted and the others seems really short too. The grow is 6 weeks in, since germinating, they were kept in propagation for 2 weeks before being replanted in to 11L pots in their final home.


Environment
The environment is tightly controlled using automation (for peanuts I might add), I will write up an article on how this can be achieved should anyone want to try. Temps and humidity are stable, due to the automation involved, however the heater became faulty over a week ago and I noticed temps dropped to 15c when lights went out, max temps have been 26c with 23c as the average temp most of the time.

The environment is as follows;
1.5m x 1.5m bud box pro
1000W Lumatek LED (currently running at 50%, 24" / 60cm above canopy to achieve ~600 PPFD)
Humidifier - Controller by automation sensors, set to turn on when levels get below 40%
Dehumidifier - Controlled by automation sensors / Currently set to operate when levels are above 50%
Internal circulation fans - 2x 9" fans in either corner, running when temps are over 19c
Exhaust and Inlet fans - Running 24/7 on a SMSCOM fan controller, moving ~220m3 p/h
Heater - Only kicks in when temps get below 19c

Medium
I'm using Canna Coco professional plus in 11L pots, I have one 12.5L air pot which I wanted to try and will be buying more for the next grow as well as automating the feeding and run off collection.

Nutrients
So again, using the full range of Canna Coco nutes, not sure if they are the best but happy to be told otherwise. Right now I'm making juice to 1.4 EC (week 6) and manually feed once a day after lights come on. Water is RO and I add the following to take it to 1.4 EC, 7ml CalMag, 5ml Rhizotonic, 25ml A + 25ml B, 25ml Cannazym, 20ml Canna Boost.

I've gone through several posts and forums, I believe this to be a Phosphorous issue but want to get your guys take on it before I make matters worse.

[HowardMarks]

Over watering imo but I’m in soil but there’s many coco growers in here that I’m sure will help you out mate

[HowardMarks]

@2-Scoops @GMO @Keeno

[Hmr81]

i was gonna say i would expect to see spots on the leaves if it was a phos issue, others will know better than me though.

i grow in coco but only ever use A+B and some sumo boost in flower tbh. Have you flushed them with ph'd water just to clear out any salt issues?

[Hmr81]

what temp is the feed at when you feed them?

[HowardMarks]

No haven't flushed yet, was thinking to do that soon. Feed temp is lower than 22c, it varies around 14-16c, is that too low? I have a Flexi tank on the way which should help stabilise water temps better, as oppose to filling up a bucket each day.

[Hmr81]

not sure what ideal temp for feed is tbh, i try and keep mine above 16c, have had plants droop like that in winter if the feed was bloody cold(my tent is in my shed).

[HowardMarks]

Looks like it could be cold roots.



I had simular with that auto haze above in pic. That was last winter with really cold feed.
Warmed the feed Nd she sorted her life out

[HowardMarks]

Ya I would agree looks like she’s cold. Just went through same get her warmer and she will shine

[HowardMarks]

It's coco so not much thst can't be fixed. Any chance of measuring the ec and pH of run off.

Either way a good flush will sort them imo. Your nutrients are solid and have everything you need. Looks like cold or possibly your ph is put in medium, measuring your run off will confirm if its pH or lock out.