Advice please...Yellowing plants

[kalimist'er]

Thanks for lookin fellas. I am having a problem with my plants directly under my 600watts. They are turning completely yellow. the other plants on the outside are fine, just the ones directly under the light. I wanna say its heat stress but not 100% sure. I have a 5inch 200cfm fan cooling my 2 600's with 6inch flanges. Room temps are 70-76 deg. Directly under the light is 80-87 deg though. I just bought a 6inch vortex to replace the 5inch 200cfm fan. The vortex has above 400cfm so I am hoping this will help. Is there something I am missing? Am I too late? I'm growing C99 and they have been in flower for 13 days.... here are some pics, lemme know what ya'll think. Thanks

 

[stinkyattic]

Fill out troubleshooting form to eliminate other sources of stress, but yes, that looks like acute heat stress that has gotten bad enough to cause necrosis on the tips. Pics are real blurry though.
Strong fertilizer mixes to the point of scorch or near-scorch will cause heat stressed plants to show more damage, FYI, which is why you should give more info.

 

[kalimist'er]

How long has this problem been going on? 1 wk to 10 days
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...) Top feed drip system on a 3x3 tray
What STRAIN are you growing? C99
What was the establishing technique? (Were the seed or clone?) Clone
What is the age of your plants? cloned, spent 2.5wks in veg and 13 days in flower so far. so about 33 days old after rooted
How tall are the plants?
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in? flowering
What Technique are you using?
What substrate/medium are you using?(Hydroton, RockWool etc.) Coco w/perlite
What is the Water temperature?
What color are your roots? White? Brown? Are your roots slimy? White
What Nutrient's are you using? How much of each if using multiple? H&G
What is the TDS/EC/PPM you are using? 1000ppm
What is the pH of the "Tank"? 5.8
Are you sure your calibration is correct on your equiptment? yes
When was your last watering? last night
What is your water temps?
When was your last feeding change? (ie. grow-bloom-micro-additional) 2wks ago
How often do you clean your system: example: Flush out water replace with clean water and nutrients? once/wk
What size bulb are you using? 600w HPS
What is the distance to the canopy? 5inches
What is your RH Factor(Relative Humidity)? 50-60%
What is the canopy temperature? 80-85 deg
What is the Day/Night Temp? (Include flucutaion range) day-75 in room, 85 at canopy- night 70 in room and at canopy
What is the current Air Flow? (cfm etc.) 350cfm
Is the fan blowing directly at plants? yes
Is your water HARD or SOFT? soft
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? R/O
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

 

[stinkyattic]

You running calmag with that RO? If yes, up to what background. If no, why not? Is H&G a coco nute?

 

[kalimist'er]

Thanks stinkyattic,

Im using the aqua flakes from House and Garden and its designed for coco in a recirculating system. I'm not using Cal Mag. I thought H&G had enough calmag in it but Ill check on that....

 

[SouthernSmoker]

Did you say that the light is less then 5 inches from the affected plants .
If so raise your light ! you are burning them

 

[MynameStitch]

Southern is correct; that is light bleaching it looks like. THe pictures are a little hard to tell since it is blurry, but it's light bleaching, raise the light up; too much lumans are destroying the plants chlorophyll.

If it's not, then it's a micronutrient issue like iron; but as for now raise that light up like by at least 1 foot above minimum.

You have to raise that light up as they grow near the light...... the damage won't recover it will stay bleached and turn necrotic later on down the road.

 

[kalimist'er]

Thanks all for the help! I raised it to 14inches above the canopy.

MynameStitch-what can I do about the bleached tops and leaves? They are pretty yellow....should i trim them? leave em? thanks for the help