Does this look like heat stress?

[@55#ER]

What STRAIN are you growing?
GHS Train Wreak

What was the establishing technique? (Were the seed or clone?)
Clone

What is the age of your plants?
Flowered 6/29

What PHASE are the plants in? (seedling, vegetative or flower) are the plants in?
Flower

What Technique are you using?
Water everyday 15 to 20 % runoff

What substrate/medium are you using?(Hydroton, RockWool etc.)
Coco -- Crop Circles

What is the Nutrient temperature?
75 F

What Nutrient's are you using?
Monkey Juice Bloom A & B

What is the TDS/EC/PPM you are using?
TDS @5 750

What is the pH of the "Tank"?
5.5

Are you sure your calibration is correct on your equiptment?
Yes

When was your last watering?
Yesterday

When was your last feeding change? (ie. grow-bloom-micro-additional)
6/29

What size bulb are you using?
400w

What is the distance to the canopy?
20 inches

What is your RH Factor?
35 to 40

What is the canopy temperature?
75 F at canopy

What is the Day/Night Temp? (Include flucutaion range)
74 to 76

What is the current Air Flow? (cfm etc.)
190 cfm

Is the fan blowing directly at plants?
Yes

Is your water HARD or SOFT?
Soft RO water TDS 4 to 8

Has plant been recently pruned, cloned off of or pinched
No

Have any pest chemicals been used? If so, What and When?
No

Are plant's infected with pest's
No

 

[MedResearcher]

Doubt its heat stress, for one because I doesnt look like it. For two cause the lower leaves are effected to, while normally the heat is coming from the bulb so the top gets it the worst. For three you said your canopy is at 75 degrees which is a nice temp... I run my ambient at 81-82 (Co2 enriched) and I only see heat stress when the tops get very close to the bulb.


I cant say for sure, but since your feeding only at 750 it shouldnt be nute burn, and if your watering everyday with run off shouldnt be too much salt buildup especially at such a low PPM.


The only thing that struck me is a PH of 5.5, to me that sounds on the edge of being to low. I use CoCo as well, I like my PH at 6.0 - 6.1, I use to use PH around 5.8 but I had more problems so I moved it up to 6.0 - 6.1 and now I dont see those problems.


Get some second oponions, but I think its your PH. I would recomend flushing with some plain PH 6.0 water, then back to your normal schedule but keep the PH around 6.0

 

[marijuanamat]

That a deficiency probably Pottasium caused by the low PPM,try upping it to 1000ppm. It shouldn't get worse but the fucked up leafs won't get better,they won't get any worse if thats the problem .

 

[Pirate138]

Id say thats a phospherous deficiency, not K. Its easy to spot cause of the curling upwards leaves. Feed more P next feeding.

 

[stinkyattic]

You're in a hydrohut? Check the 'hydrohut syndrome' threads/pics to eliminate that.

Could be a straight K deficiency, but I have a hard time buying that one because of the absence of the characteristic rusty spotting of the lower leaves that accompanies a simple K def. If anything, I'd say an extreme K LOCKOUT by excess Na.

Couple things- If you did not thoroughly rinse/leach your coco before use, and it is not written on the packaging that it was pre-rinsed, there is a strong possibility that there is sodium and potassium remaining in the medium. And what I see there looks eerily like a salt burn compounded by higher temps (you're not TOO high, but tox shows up worse in higher temperatures). The worst of salt burn is actually a severe potassium lockout.

If you aren't running CalMag, you should be.

Your runoff% looks good, now check the runoff PPM as well and compare to the ppm IN.

Your 'res'- drip to waste I take it? How well are the nutes chelated? Your symptoms also make me think of what happens when you pre-mix nutes that aren't meant to be pre-mixed. Is it possible that you could be getting interactions among your fert components? Have you tried a nute system designed specifically for reservoir type applications, if the one you are using does not specify that? Canna coco ftw... really... nice shit.

Bring pH to 6-6.2- you're a bit low for soilless/coco.