Looks like heat stress but isn't. Help! - Cannabis Infirmary - International Cannagraphic Magazine Forums

makeitfunky · 01-12-2018, 06:37 PM

Hi, my plants are showing signs of heat stress (I think). Leaves curling upwards at the edges but the temps and humidity are fine. What else could it be?

Background info:

Original Glue in 8L pots in Coco.
4th week of Veg.
1000w HPS about 1.2m above canopy.
Temps 25c day 20c night
RH 60%

Feed EC 1.8-2.0
2.5mls/L Coco Specific A+B and 0.5mls/L CalMag
ph5.6-5.8
3 times a day in DTW

I was running in to a cal mag def (I think as was running a low EC 1.2-1.4) So have upped it with a bit of CalMag which seems to have done the trick apart from the leaf curling. Its all over the pant top and bottom so def isnt heat.

Pease see pics and help really appreciated.

Thanks

maimunji · 01-12-2018, 08:12 PM

Double check your ph with ph strips. Looks like its off.
Drop cal mag because you are not far away from lockout. 2.0 is extremely high and if you continued to feed with this rates you will overfeeding everything and will finish with crap.

makeitfunky · 01-12-2018, 08:34 PM

I will try that thanks. I have a ph pen that calibrated to 7.0 but maybe it’s off at the lower end?

My tap water is 0.4 so I thought there would be no need for CalMag but I was def having defecencies before. Any more ideas anyone? In case pH IS correct?

Could it be something to do with the Coco?
Also could it be to do with the coco getting cold? Cold air is drawn in near the bottom of the tent

makeitfunky · 01-12-2018, 08:36 PM

Also what nutrient is lacking to cause heat stress type symptoms?

Lester Beans · 01-12-2018, 09:04 PM

Your pH is too high. 6.0-6.1 for coco.

Also you ec seems really high.

makeitfunky · 01-12-2018, 09:14 PM

Thanks I will change the PH to 6.0 and also lower E.C

Do you think CalMag is necessary?
If I add maybe 2mls/L A+B and 0.25mls/L CalMag E.C would be about 1.4 does that sound ok? What would you recommend?

Lester Beans · 01-12-2018, 11:29 PM

That sounds about right. I would def us cal mag.

You caught the issue early so good eye. They should be back to normal very soon.

Make sure to flush some before resetting feed. I would flush with proper pH water.

Athos · 01-13-2018, 01:04 AM

I had the same issue happening to me last run, leaves looked the same as yours. It was pH been too high.

01-12-2018, 06:37 PM	#1
makeitfunky Newbie Join Date: Jan 2018 Posts: 43	Looks like heat stress but isn't. Help! Hi, my plants are showing signs of heat stress (I think). Leaves curling upwards at the edges but the temps and humidity are fine. What else could it be? Background info: Original Glue in 8L pots in Coco. 4th week of Veg. 1000w HPS about 1.2m above canopy. Temps 25c day 20c night RH 60% Feed EC 1.8-2.0 2.5mls/L Coco Specific A+B and 0.5mls/L CalMag ph5.6-5.8 3 times a day in DTW I was running in to a cal mag def (I think as was running a low EC 1.2-1.4) So have upped it with a bit of CalMag which seems to have done the trick apart from the leaf curling. Its all over the pant top and bottom so def isnt heat. Pease see pics and help really appreciated. Thanks Attached Thumbnails
	Quote

01-12-2018, 08:12 PM	#2
maimunji Senior Member Join Date: Apr 2015 Posts: 1,261	Double check your ph with ph strips. Looks like its off. Drop cal mag because you are not far away from lockout. 2.0 is extremely high and if you continued to feed with this rates you will overfeeding everything and will finish with crap.
	Quote 1 members found this post helpful.

01-12-2018, 08:34 PM	#3
makeitfunky Newbie Join Date: Jan 2018 Posts: 43	I will try that thanks. I have a ph pen that calibrated to 7.0 but maybe it’s off at the lower end? My tap water is 0.4 so I thought there would be no need for CalMag but I was def having defecencies before. Any more ideas anyone? In case pH IS correct? Could it be something to do with the Coco? Also could it be to do with the coco getting cold? Cold air is drawn in near the bottom of the tent
	Quote

01-12-2018, 08:36 PM	#4
makeitfunky Newbie Join Date: Jan 2018 Posts: 43	Also what nutrient is lacking to cause heat stress type symptoms?
	Quote

01-12-2018, 09:04 PM	#5
Lester Beans Frequent Flyer Join Date: Nov 2011 Location: ~ In The Garden Pulling Weeds ~ Posts: 3,633	Your pH is too high. 6.0-6.1 for coco. Also you ec seems really high.
	Quote 1 members found this post helpful.

01-12-2018, 09:14 PM	#6
makeitfunky Newbie Join Date: Jan 2018 Posts: 43	Thanks I will change the PH to 6.0 and also lower E.C Do you think CalMag is necessary? If I add maybe 2mls/L A+B and 0.25mls/L CalMag E.C would be about 1.4 does that sound ok? What would you recommend?
	Quote 1 members found this post helpful.

01-12-2018, 11:29 PM	#7
Lester Beans Frequent Flyer Join Date: Nov 2011 Location: ~ In The Garden Pulling Weeds ~ Posts: 3,633	That sounds about right. I would def us cal mag. You caught the issue early so good eye. They should be back to normal very soon. Make sure to flush some before resetting feed. I would flush with proper pH water.
	Quote

01-13-2018, 01:04 AM	#8
Athos Member Join Date: Jan 2015 Posts: 211	I had the same issue happening to me last run, leaves looked the same as yours. It was pH been too high.
	Quote

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