Leaves cupping and one plant turning yellow

Hey everyone

Im using GH grow, bloom, micro. I have just upped the nutrients to mild strength and now i am noticing the leaves turning yellow at the centers and brown spots. I am thinking i need to add epsom salts. Also some of the lower leaves are cupping upward. I have posted pics these plants are 4 weeks old from seed. Please help and thanks for any replies.

Oh and I was away for to weeks and the wife was watching them they will be potted tonight.

Looks like nute burn or ph too low or both.

My Grow Journal: https://www.rollitup.org/grow-journals/169213-lollipop-white-widow-blueberry-sadhu.html

atmt888 said:

Looks like nute burn or ph too low or both.

My Grow Journal: https://www.rollitup.org/grow-journals/169213-lollipop-white-widow-blueberry-sadhu.html

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Ditto...nute burn. Don't add epsom salts, either -- that will def make things worse. What you're seeing is a product of too many salts in the medium as it is.

its has been a day and its just the one plant showing the burning and it is getting worse. I have dumped half the nutes and added PHed water to bring the level back up. I was using hydron PH strips but decided to go buy a PH pen today. Ph in the solution was 6.0 and now after adding the PHed water it is 5.8. I am using tap water and am still thinking the pics atached here looks alot like the one for mag def in the plant abuse thread. I will watch and see what she does with half strength nutes. and if it gets worse I will try somthing else. Also it is happening only to the older leaves near the bottom. I am a newbie and am in dire need of some more advise. If it was nute burn will the leaves heal or should I snip them off?

666satan666 said:

its has been a day and its just the one plant showing the burning and it is getting worse. I have dumped half the nutes and added PHed water to bring the level back up. I was using hydron PH strips but decided to go buy a PH pen today. Ph in the solution was 6.0 and now after adding the PHed water it is 5.8. I am using tap water and am still thinking the pics atached here looks alot like the one for mag def in the plant abuse thread. I will watch and see what she does with half strength nutes. and if it gets worse I will try somthing else. Also it is happening only to the older leaves near the bottom. I am a newbie and am in dire need of some more advise. If it was nute burn will the leaves heal or should I snip them off?

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The leaf margin curling up is a sign of nute burn but the spotting looks more like ph to me. Why did you lower your ph if it was already too low? Soil ph is suppose to be 6.8 and I think hydro is suppose to be a little lower but 5.8 IS too low. IT IS NOT MAGNESIUM DEFICIENCY. Look at the pics in this sick plant guide: http://www.icmag.com/ic/showthread.php?t=11688 . Your spots look nothing like magnesium deficiency and dont match any of the symptoms. Magnesium doesnt get locked out in hydro unless your ph falls below 5.8. Get your ph up to 6.5 and back the nutes to 25% max until you can get a better idea of whats going on. Nute burn won't heal but dont cut off the leaves until they are totally dead as watching them will help you learn whats happening and know when it has stopped happening.

atmt888 said:

The leaf margin curling up is a sign of nute burn but the spotting looks more like ph to me. Why did you lower your ph if it was already too low? Soil ph is suppose to be 6.8 and I think hydro is suppose to be a little lower but 5.8 IS too low. IT IS NOT MAGNESIUM DEFICIENCY. Look at the pics in this sick plant guide: http://www.icmag.com/ic/showthread.php?t=11688 . Your spots look nothing like magnesium deficiency and dont match any of the symptoms. Magnesium doesnt get locked out in hydro unless your ph falls below 5.8. Get your ph up to 6.5 and back the nutes to 25% max until you can get a better idea of whats going on. Nute burn won't heal but dont cut off the leaves until they are totally dead as watching them will help you learn whats happening and know when it has stopped happening.

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Yeah, that definitely looks like a pH problem. I'd say this is the best advice you can get.

That leaf curling at the edges is usually heat related.
Do you have a fan blowing on them?
How close are your lights, and what lighting are you using.
Apart from that they look pretty good.
I dont see any signs of nute burn or ph issues.

Also 6.5 ph is to high for hydro, 5.5 to 5.8 is good.
6.5 to 7 for soil.
The spotting is most likely caused from your nutrient mix splashing on the lower leaves.

I am using a 400 watt MH that is about 50 cm from the plants. will be switching to 1000 watt HPS in flower room. There is a fan blowing on med across the tops. They are in rockwool that has been placed in clay pebbles. I can see the nutes being splashed on the leaves because the pump puts out pretty good.

666satan666 said:

I am using a 400 watt MH that is about 50 cm from the plants. will be switching to 1000 watt HPS in flower room. There is a fan blowing on med across the tops. They are in rockwool that has been placed in clay pebbles. I can see the nutes being splashed on the leaves because the pump puts out pretty good.

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That's Good, I honestly think they are looking really good, those lower leaves don't last very long anyway and get sacrificed by the plant as higher leaves start blocking the light.
The leaf curling is really nothing to worry about, but obviously would be better without it.
I had some huge problems with heat in summer but it all worked out OK.
I'm in Australian sub tropics and summer was a killer, 36C most days with very high humidity, so it was extremely hard to keep an indoor grow cool.
I'm adding some pics taken this morning after 7 1/2 weeks of flowering just to show similar leaf edge curling, which has been with them for the entire grow.
As you will see it hasn't affected budding.

Dude the liquid on leaves is gonna kill them fast, lol. Like a mag glass.

I saw barely any nute burn, Like you hit the back off point that is all.

the leaf cup is from the heat. Some plants cannot tolerate ANYTHING over that 77 literally. Their sisters can do just fine.

Keep it a little lower. if it is all plants raise the hood. You will be fine.

Hydro ph has to be 5.8 nothing else. Everything else is just lucky. and you can get lucky, but the chart is obvious.

keep that fan on and use good exhaust and I only saw some bagseed go ok over 80 degrees but the bud is wacked.

666satan666 said:

I am using a 400 watt MH that is about 50 cm from the plants. will be switching to 1000 watt HPS in flower room. There is a fan blowing on med across the tops. They are in rockwool that has been placed in clay pebbles. I can see the nutes being splashed on the leaves because the pump puts out pretty good.

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/facepalm nutes on leaves is a no no unless youre foliar spraying. Try adjusting the pump or sprayer until its not getting water on the leaves. If this isn't possible you could always put a skirt around the base of you plants. If you can hold your hand at the top of your plants for 1 minute and it isn't hot then it's probably not heat stress. I have had a grow where it looked like I was getting heat stress but really there was just so much air blowing on the plants they were over transpiring. Looked exactly the same but was only happening close to the fans. I assume this is rare but it may be something to keep in mind if you have high air flow.

atmt888 said:

/facepalm nutes on leaves is a no no unless youre foliar spraying. Try adjusting the pump or sprayer until its not getting water on the leaves. If this isn't possible you could always put a skirt around the base of you plants. If you can hold your hand at the top of your plants for 1 minute and it isn't hot then it's probably not heat stress. I have had a grow where it looked like I was getting heat stress but really there was just so much air blowing on the plants they were over transpiring. Looked exactly the same but was only happening close to the fans. I assume this is rare but it may be something to keep in mind if you have high air flow.

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This is also happening to the plant that is closest to the fan. I have moved it since and it appears to have stopped. I will be watching the one that is close to the fan now and mabey back the fan off if it starts happening again.

Spiked1 i hope i can grow nuggs that look like that. Thanks for sharing the pics they are insane.

666satan666 said:

This is also happening to the plant that is closest to the fan. I have moved it since and it appears to have stopped. I will be watching the one that is close to the fan now and mabey back the fan off if it starts happening again.

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Awsome! I'm glad it was a simple fix for that symptom at least. From my experience margin roll from wind isn't that big a deal and doesn't seem to affect harvest. Usually, if there isnt a ph reason, margin rolling is heat stress or wind stress. Typically wind stress won't go beyond the margin roll unless you got an industrial fan a foot from your plants. It's heat stress that is the real problem and it can strike very very fast.