Bright Yellow Patches & leaves Turning Down, & Some plants turning up! - Any Advice?

Hi all, this is my first grow, sort of a fumble my way through job! my plants are into their 7th week of flowering now, we only started using nutes since week 4, but only in light amounts

the plants are generally healthy but over the last few days one has had problems with the leaves turning down & bright yellow almost dayglow patches on the dark green leaves, any ideas what could be causing this?

some of the other plants leaves are turning up, as in the 3rd picture, is this a symptom of heat stress? using a 400w HPS light, bout a foot away from the tops with a small fan circulating to cool abit

Any advice would be appreciated

Thanks

Exactly!
Your plants are showing two of the three most common symptoms of heat stress: Upcurled edges from a high temperature:humidity ratio, and actual burn patterns on the leaves where what would have been a mild fertilizer problem has turned into necrotic burned areas. The last symptom would be an overal yellowing of the plants.

Fill out the troubleshooting form, and tell us as much as you can about how your room and exhaust is conficgured, and the lights.
Finally, can you get a close-up of the curled-UNDER leaves in pic #1? There are two or even three things going on there (heat, a possible Mg issue, and the possibility tyhat the plant is either rootbound or N overdosed) and we can figure it out with more information.
You're close to harvest I see so it will mostly be heads up kind of info for next time. Honestly the plnats look like they had been doing very well for a long time.

Thanks for the info stinky, im not too clued up on our exact setup! lol we got a whole job lot 2nd had kit, have attached some more pics, sorry can only take them with my iphone, have taken a pic of the extraction we have too

1.5m2 grow tent
E-indoor
E-soil,
E-
CSL-Miraclegrow
SCL-
SCLR-
E-bathroom tap
E-Source water pH
HRT-)
E-4 months
E-Aarde A&B Nutrients (A - 8-0-11 B - 2-4-10) 1.5ml per 1ltr + Bud booster
E-
E-400w HPS 1ft away from plant
E-75/50)
HD-Reservoir temperature
E-
E-12/12
E-an extractor with filter(came with kit)

We also have a small radiator in the tent on 24/7 as our nights are nights are nearly freezing

What brand of tent? Have you ever heard of hydrohut syndrome?
How big are your pots? Have you ever flushed your plants, and checked the pH?
It also seems that the worst of the stripe damage is in a line, as if it was all caused during the same time period, but that the stressor may no longer be there. Have you recently raised your lights, or did you at some point give them too much feed?

Not sure what brand of tent it is, got it all in a job lot,

Pots are 3 gallon ones I think, have recently (3 weeks ago) upgraded them as think they were become rootbound, never really flushed the plants, check the PH from time to time but only with some electronic prong thing you put in the soil, but said it was close enough to 7 all the time, what is the best way to test the PH?

We did raise the lights a couple of inches when we saw the leaves turning up etc, what sort of hight should a 400w be from the tops? they leaves are still remaining folder up though, should they relax & go flat again?

dont think we have ever given it too much feed (all the others got the same amount and they seem fine) it is just the 1 plant that has these extreme yellow patches, the others are all green, but on some of them the leaves are folding upwards

we are at week 7 of flowering now so you are correct that this will be for my knowledge the next time round where we will use a proper course of nutrients, and not just randomly giving them some like this time ;)

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We did raise the lights a couple of inches when we saw the leaves turning up etc, what sort of hight should a 400w be from the tops?

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400MH...16 inches....400HPS 12-15 inches...above the canopy. IMO. This zone should be at 78 degrees (ideally) with good, fresh air flow.

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Not sure what brand of tent it is, got it all in a job lot

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I hope, it's not a HydroHut Death Tent?

hmm so my light appears to be the right height from the plants,

Here are some more pictures, the 1 plants seem to be getting worse! what could be causing the yellow patches? it is only near the top of the plant,

on the other plant the leaves are still curling upwards and there seems to be brownish speckles appearing on the leaves (cant really get these to show on the photos

What is this death tent of which u speak?

Can you get us a runoff pH number as soon as possible?
The HydroHuts made about 1-2 years ago outgassed toxic fumes that killed plants.
But you have other stuff going on, like the taco leaves that say your heat is too intense and your humidity too low.
Those stripes DO resemble damage from a severe Mg deficiency but don't look quite right to say for sure. Even so, making up a spray bottle of 1/2 teaspoon epsom salts per quart of water with one drop dish soap, and LIGHTLY misting the plants with it, NOT ON THE BUDS!!!, will halt the spread of Mg def if that is what it is, and not harm the plant if it isn't.
But get that pH number asap. You may need to do a heavy flush very soon.

Hi, sorry bit of a n00b, how would i get the PH rushoff? not sure all that stuff will be available form me to do, still learning the ropes

Do you think it wil see out the next 2 weeks? should be ready to harvest by then

thanks in advance

How about a photo of the hut itself?