Problem in Coco, Mag Def?

[Hereward]

Hey guys I've been running the Head/Rez 6/9 GH micro/bloom mix in Canna Coco for a while now with consistently great results until this week a flower room of 8 plants all in 2.5 gal coco pots handwatered twice daily are looking seriously hungry. I suspect magnesium deficiency. The other problem is these are newer strains to me. They are G13, Williams Wonder, LA Confidential and AK47. All show the same symptoms. In addition to the micro/bloom they get fed half a gram epsom salt per gallon plus some silica blast and that's all. Except I gave them 10ml bushmaster kangaroots root drench a couple weeks ago. They are day 12 flower.



How long has this problem been going on? About a week
Are you growing in a PVC grow tent? (example: Hydrohut or any other non brand tents)no
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...)handwatered coco twice a day with good runoff
What STRAIN are you growing?williams wonder, ak47, g13, la condidential
What was the establishing technique? (Were the seed or clone?)clones
What is the age of your plants?day 12 flower
How long have they been in there mixture they are in now?(coco,soiless etc..)4-6 weeks
How tall are the plants?3-4 feet
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in?flower
What Technique are you using?handwater coco till runofff
What substrate/medium are you using?(Hydroton, RockWool etc.)coco
What is the Water temperature?sixties
What color are your roots? White? Brown? Are your roots slimy?white when i see em
What Nutrient's are you using?(If growing soiless)general hydropics
How much of each nutrient are you using with how much water? 6ml micro, 9ml bloom, half a gram epsom salt*Knowing the brand is very helpful*
How often are you feeding? (If using soiless)twice a day
How often are you giving nutrients? (If using soiless)every watering
If flowering, when did you switch over to using Bloom nutrients?feed didnt change
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)micro, bloom
What is the TDS/EC/PPM you are usingtap water only 75ppm, nutes mix up to around 800 or a little more
What is the pH of the "Tank"?800
How often are you testing your pH/PPM/EC/TDS?ph at least daily, ec just here and there
Are you sure your calibration is correct on your equipment?yes
When was your last watering?earlier tonight
What is your water temps?around 68
When was your last feeding change? (ie. grow-bloom-micro-additional)
How often do you clean your system: example: Flush out water replace with clean water and nutrients?
What size bulb are you using?1000 watt hps
How old is the bulbs you are using?getting old, over a year.
What is the distance to the canopy?24 inches or so
What is your RH Factor(Relative Humidity)?30%
What is the canopy temperature?79
What is the Day/Night Temp? (Include flucutaion range)room is mid 70s light on, 60s light off
What is the current Air Flow? (cfm etc.)CO2 supplemented but gets ventilated for 15 minutes every 3 hours
Tell us about your ventilation, intake exhaust and when its running and not running ?
Is the fan blowing directly at plants?no, but an oscillating fan blows gently over canopy
Is your water HARD or SOFT?soft from tap
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?tap
If using tap water, what is the ppm/EC/TDS of the water right out of the tap?75ppm
If using RO,Distilled,mineral water, what is the ppm/EC/TDS without any additives?
Are you using water from a water softener?no
Has plant been recently pruned, cloned off of or pinchedsome where recently supercropped, but the non-supercropped ones have the exact same problem
Have any pest chemicals been used? If so, What and When?sprayed with forbid, and watered with bayer advanced citrus/vegetable imidicloprid before going into flowering about 2 weeks ago, also use mosquito drops
Are plant's infected with pest'sno, but seen larva squirming in a different plants coco in a different group

 

[Hereward]

 

[RubeGoldberg]

100-150 ppm of a hydro store cal-mag product with feedings AND waterings

also make sure the PH going in is at 5.8-6.0



Coco will naturally lock out most of the cal-mag in a standard hydroponic nutrient, when running it you either need a coco specific nutrient or you need to supplement cal-mag on your own.

This should clear up for you except for the necrosis spots, but they should hopefully bounce back pretty good this early in flower

 

[crazybear]

You have any bugs?

 

[inreplyavalon]

I would test your runoff ec before adding calmag or any other elements.
I find that with the switch to flower it is very easy to overfeed and being as you are still in the transition this is when it can show itself.

 

[Darth Fader]

Some of the later pics look like Mg deficiency, but you are feeding enough Mg, so that would indicate either you're PH is out of range, or lockout. Feed at 5.8pH and measure the ppm of your runoff. You probably have salt buildup locking out the Mg and you're just going to need to flush those salts out with a lot of runoff. If you're feeding at 800ppm I would flush with half-strength solution (400ish) until your runoff is under 1000ppm. I'd be willing to bet it's waaaayyyy higher. Also, why no calcium? Seems to be absent.

 

[Hereward]

RubeGoldberg:
Well the last two days I've been adding General Organics CaMg+ at 5 ml per gallon. This raises my TDS by about 165 ppm. This brand has 5% calcium and 1% magnesium and adds no nitrogen or anything else. Does this sound good? I'm still adding half a gram epsom salt. This can't hurt can it? I'm watering 2-3 times a day with good runoff and I'm now double checking ph before each watering.

Crazybear:
Well I've seen a couple gnats flying around the room the last couple weeks. Been using BTi mosquito drops for many months, but about two weeks ago sure enough I saw hundreds of tiny white squirming larva float up in the coco of a maturing Williams Wonder I was watering, which has since been harvested. After seeing that I've been staring real close and real long at the coco of every plant with every watering. Funny thing is I haven't seen a single larva float up in any other plant yet. Also, the next day I watered every single coco plant I've got except for the ones within 6 weeks of harvest with Bayer Advanced Citrus/vegetable imidicloprid product at half an ounce per gallon. That was almost two weeks ago. Today to be extra safe I drenched this sick group of eight with an oz per gallon of azamax.

Inreplyavalon and Darthfader:
Okay I'm definitely testing my runoff when lights come on tomorrow. This problem is really throwing me. I've been running this program pretty much the exact same way for a long time and have never seen anything remotely like this before. These are the saddest looking plants I've ever grown and it's really bumming me out. They're looking really limp and weak and dried out. The last few hours of lights on the leaves get really droopy and limp almost like wilting.

 

[Hereward]

Update guys: We took lots of runoff readings today and the results are mindblowing! Now I've maintained my input water the last 3 days at precisely 5.9 ph and with the organic calmag has a consistent TDS of about 930 ppm. These are checked before each watering with a digital milwaukee ph meter, then confirmed against ph drops. The meter is calibrated daily and is consistent. The runoff readings from todays 2 waterings were very consistent with each other.

Average runoff readings:
ph: 6.4
tds: 687

And my input is 5.9 and 930!

What causes this? Is it possible I've locked out potassium?

As I've said the problem really became evident upon there introduction into flower and just gets worse. Could the environment change contribute to this? The veg room typically has a relative humidity in the 70s while this flower room is 30s. Also, the week before they were introduce into flower we had that major heat wave and my veg room temp got into the eighties and humidity hit 90. The plants were under 1000 watt MH on movers. That week the plants experienced a huge growth spurt, but in a bad really stretchy way.

 

[RubeGoldberg]

PH seems fine, the plants are pulling nutrients from the water so the PH will climb, its well within a reasonable range for your plants to uptake nutrients.

That cal-mg you went and purchased should clear things up for you.

looking back up at the top it mentions you feed twice a day? any particular reason for this regimen? does it dry out if you dont?

 

[RubeGoldberg]

also, have you been able to take a peek at the roots? considering its been warm in your room and the roots are getting watered twice a day it is possible that you could have some kind of problem in the root zone.. root rot pathogens tend to really take hold and become noticeable in the leaves around week 2 of flower once the buds start to first form, I guess because the plant tends to become weaker then

 

[Snow Crash]

You definitely have some pretty bizarre shit going on man. I don't think I'd put my money on a mag deficiency. I think it looks a little like a Phosphorus or Calcium thing... Maybe Potassium. Really bizarre though.

My first question is how much runoff you are collecting? This is important information to have in order to make sense of the readings you are getting.
My second question is if it is progressing and which leaves on the plant are being affected (where they are on the plant)?
What's with the very low RH?

Hope I can assist.

 

[dgr]

RubeGoldberg:
...but about two weeks ago sure enough I saw hundreds of tiny white squirming larva float up in the coco of a maturing Williams Wonder I was watering, ...
Also, the next day I watered every single coco plant I've got except for the ones within 6 weeks of harvest with Bayer Advanced Citrus/vegetable imidicloprid product at half an ounce per gallon. ...Today to be extra safe I drenched this sick group of eight with an oz per gallon of azamax.

...They're looking really limp and weak and dried out. The last few hours of lights on the leaves get really droopy and limp almost like wilting.

Hereward,
Based on what you've written, I would perform a root-ectomy. It sounds to me like there is root damage and there aren't enough roots to support your plants.

 

[Lain]

In 4-6 weeks in 2.5 gallon pots under a 1000w, those roots can grow pretty fast and fill a container in that time frame if you're not using air/smart pots.

I don't want to scare you, but tiny white larva = root aphid larvae or fungus gnats?

Thats probably what's causing phantom leaves to drop as the pests feed on the roots, deep in the medium.

Either or; they are doing damage to your root zone if you're finding hundreds floating up when watering.

Your plant needs roots now more than ever to keep up with heavy demand of bud sites.

Wouldn't hurt to foliar feeding with a 1/4 strength solution, trace elements, and a kelp product. IMO a vitamin/immune system boost would help the stress a lot right now.

 

[Hereward]

Hey guys I really appreciate the responses. Here's an update.

Todays first watering:
Input water: 5.7ph, 950 ppm
Runoff water: 6.6ph, 716 ppm

Second watering:
Input: 5.5ph, 950 ppm
Runoff: 6.6ph, 753 ppm

Zero larva sightings, not losing as many fan leaves, slight increase in perkyness, still kinda yellowish all around.


RubeGoldberg:
I always water my coco (2/1 coco/perlite) two, if not three times daily in the flowering room, always once daily in veg. In my experience with coco so far I've noticed the plants always seem happier and grow a lot faster when I water more often and problems only show up when I slack and skip waterings. It felt really counterintuitive at first since i was primarily a soil grower before, but I've learned to treat coco like a hydro medium and it's paid off until now. Also, I tend to follow very closely the advice of GratefulHead in his 'Head goes coco' thread. It's stickied in the coco forum, definitely check it out if you havent yet. One of the coco principles I've concluded from that discussion is: When in doubt, increase watering frequency, assuming the plant is well rooted and in conditions conducive to strong growth. Watering frequently in coco pulls fresh oxygen through the medium, results in more stability of ph/tds, and will keep salts fully dissolved preventing burn.
I should clarify that the flower room they're in has been pretty consistently in the low to mid 70s always. It was the veg room that was too hot for a week. I suppose they could have caught some root disease in that hot/wet condition that's just now becoming really intense. But there are sister plants still in veg that went through the exact same experience and aren't showing symptoms. I'll do some root exploration tomorrow when lights are on.

Snow Crash:
Lately I'm getting roughly half a liter or more of runoff from each plant with each watering. The plants sit on ebb and flow trays so when I want to take runoff reading I collect a cupful of the water as it runs out the drain hole of the tray and I intercept it before it goes to the bucket.
This seems to be affecting leaves all over the plant from top to bottom. If i had to say though, I'd say its older fan leaves getting hit the worst. Those dead fallen off leaves I photographed were from the lower-middle of the plants.
I didn't think humidity in the 30s was too low for a flower room. But yeah it seems to stay in the 30s to 40s pretty consistently from the superior AC in that room.

dgr:
I'll do some exploratory surgery into my roots tomorrow, I'll definitely post what I find.

Lain:
It was a different plant I saw all the gnat larva in, I havent seem any larva float up in any of this group, not yet anyway. I am watching very closely I assure you. Yeah I thought about root aphids, but don't know enough about them yet. Do they have a larval stage? Where abouts in the rootzone would I be most likely to find them if theyre there? Doesn't the Bayer Advanced kill all these types of insects?

 

[RubeGoldberg]

the "larvae" you saw float up to the surface, did they squirm back down right away?

 

[Hereward]

the "larvae" you saw float up to the surface, did they squirm back down right away?

Yes, they don't seem to like the surface at all. They looked like hundreds of miniature maggots, white and squirmy but rather fast moving too. They look consistent with what I know about fungus gnat larva, but I've been adding Bacillus thuringiensis products to my res for months now. To be clear though, I still haven't seen them in the coco of these plants with the current problem. However, the plant that did have them did start having similar mystery symptoms beginning about halfway through flower. I didn't notice the larva in that plant until about a week or so before harvest.