Not sure what to do here....?

[Gangabiss]

I've got 8 Sex Bud coming up to 5 weeks flowering now and 3 of them are displaying this strange curling of the leaves near the top of the plants. this doesn't seem to be happening at the very top or bottom, only between the middle and top of each plant.
All 8 are yellowing slightly from the bottom up, however it's only these 3 plants showing this weird curling phenomenon.
They re curling down at the sides as well as along the length, leaving them looking like curled tubes rather than flat leaves....
Temps are quite high probably hitting 90* at leaf height if that matters.

Here's a few pics to show what I mean:



Basically I think I just need confirming wether I need to either up my nutes or lower them...I'm guessing it's a nutrient sensitivity issue seeing as they are all from seed and only 3 of 8 are showing these symptoms.

 

[rexamus616]

temperature can have that effect mate.....

looking good otherwise!

 

[justanotherbozo]

...yeah, sativas are notoriously lite eaters so i'm thinking nitrogen toxicity is probably the problem, heat can cause issues similar to this for sure but i think you just need to back off the nutes and see if it continues or if it stabilizes.

...it's unlikely that the curled leaves will uncurl so watch the new growth.

good luck, bozo

 

[Teddybrae]

I reckon those leaves are trying to get away from the light.


can't see the "... yellowing slightly" you mention.


also wondering how the plants being from seed ... and three out of eight having curled leaves ... means there's nutrient sensitivity. ?


could it be your soil is not evenly mixed? perhaps three of your pots have too much of one thing or another ... or not enough ... and that is what is affecting your plants.


cheers!

 

[Gangabiss]

Cheers for replies!

All are potted in All Mix so they re ll in the same boat, that's what made me wonder if it was a nute sensitivity issue as only some are being affected but all are in the same conditions. I would've assumed if it was heat stress that they would all be suffering?

Nitrogen toxicity was my thought also, however as I said they are also yellowing from the bottom up and have all lost their bottom few sets of leaves in the past couple weeks. They went totlly yellow just like a nitrogen deficiency would show, which is why I'm dubious as to wether this could be N toxicity. Also I've overfed my plants before and they went a much darker green all over and had 0 yellowing leaves, finally going dark green/blue and started browning on the leaf edges....nothing like this.

All I know is I'm pretty sure I've never run into this problem before from underfeeding my plants. This does seem like a toxicity problem or too much heat....basically too much of something lol

 

[Gangabiss]

I should add that these curling leaves seem to have a dry, faded green look, whereas the rest of the leaves on the plant are a much more rich, vibrant green and have shine to them.

Also, they are all in 5l pots which means they may be slightly maxing out their pots right now. Could this be a symptom of them being rootbound?

 

[Teddybrae]

OK. so these plants are not young ... right? so is there a possibility the yellowing is "senescence"? you know, the plant are reaching or are approaching the end of their life and are putting all their nutes into flowering. sativas will do that ... begin to yellow at end of life.

otherwise ... are your nutes fresh or at least not old?

have you checked pH ... especially if the plants have a bit of age on them.

Also you may have nutrient imbalance at a late stage ... so a flush may be in order.

so ... how close to flower or finish are these?


cheers!

 

[Teddybrae]

PS ... and if yr plants are not old then you must suspect they are root bound and are just not processing the nutes as they should. Re pot.

Out ...

 

[Gangabiss]

They are not young but also not exactly at the end of their life either. They're at nearly 5 weeks flowering so still another 3+ weeks left. Surely they shouldn't be eating themselves alive this early? I know that plants tend to yellow as they near harvest but I've never seen them do this before and I've grown for around 8 years.

I'm unable to repot them as I'm just about to fill the tent with a new round of clones so there will be no extra space left.

So far I've backed the 600hps off them and I will dial back the nutes when I feed them tonight. I can't think of anything else I can do to help them at this stage.

Oh and they are in organic soil with organic nutrients so flushing is out of the question. Nutrients are not old.

Could this be a magnesium deficiency? I have recently run out of alg-a-mic (seaweed extract) so maybe this could be the culprit? I know some plants are more sensitive to mg than others so require more for normal healthy appearance.

 

[Gangabiss]

And for people saying they can't see the yellowing, look at the 3rd picture, you can clearly see the leaves get more and more yellow as they go down the plant.

This is what makes me think it cant be overfeeding.

 

[Lester Beans]

Good start, you got the light backed off. Now get the heat down some, and feed some nitrogen to the plant. A good veg nutrient should help.

 

[MrBungle]

I think this is a VPD issue...I used to get this claw when my vert box temps and humidity were all out of wack...

 

[Gangabiss]

Thanks Lester, I have just given them an extra dose of nutes as I figured with all the yellowing and the general faded green look of the leaves it couldn't possibly be an overfeeding issue.

What is VPD? I agree it is quite likely that the clawing is due to the heat and/or low humidity. This all seemed to start when I swapped out one of my 315w CDM lights for a 600w hps....the heat difference is insane!

 

[MrBungle]

VPD stands for Vapor Pressure Deficit, and "it's the difference between the theoretical pressure exerted by water vapor held in saturated air (100% RH at a given temperature) and the pressure exerted by the water vapor that is actually held in the air being measured at the same given temperature"


http://www.just4growers.com/stream/...-deficit-the-hidden-force-on-your-plants.aspx


I'm learning about it right now too....So it isn't exactly easy to explain

 

[Guy Brush]

For me it looks also water related. Do you keep them moist all the time, i.e. are overwatering probably?

 

[Gangabiss]

You know what I just noticed last night half way through watering them that they were still quite heavy when I picked them up. I've been watering every day so I'll give them an extra day to dry out this time. You might be on to something there.
I did used to always add perlite to my all-mix before this and now I think I'm remembering why I started doing that...

 

[Guy Brush]

You know what I just noticed last night half way through watering them that they were still quite heavy when I picked them up. I've been watering every day so I'll give them an extra day to dry out this time. You might be on to something there.
I did used to always add perlite to my all-mix before this and now I think I'm remembering why I started doing that...

At icmag we are always on to something here
I believe half the problems on the site are from overwatering. Best to check the pots every day, like you did now.