Burning toast

[smokey the cat]

A few days ago

A little light stressed right, but is this anything to really worry ab....

Oh.

Last night.

Lesson: Retrofitting a cab with mylar a week shy of finish was a bad idea.




Leaf curl - means dial it down yo.

a

(Image blatantly ripped off from from https://www.rollitup.org/marijuana-plant-problems/808223-whats-wrong-leaf.html)

 

[SupraSPL]

Dang that bud looks fat and frosty It is at 7 weeks?

 

[smokey the cat]

Not sure when they went into flower - lol, but I'd guess day 54-56.

Decided to cut the plant last night to avoid any last minute stress-bananas. Trichs 80% cloudy, 15% clear and 5% amber - just a few days short of where it should be. The leaves turned an awesome black colour tho - absolutely stunning.

Other plant has less damage and is still going. It's running a few days behind the chopped plant - I'll give it one more week under half the previous light.


Vero 18 at 50W - stay at least a foot from emitter. Maybe 2. There was some light damage from Vero with cream walls - but when I retrofitted the cab with mylar my plants blacked like a bruised ripe banana overnight.

 

[hyroot]

It looks like heat stress. Leaves flare up like that to cool itself off. Like when a dog is panting. If anything it could cause buds to be less dense. Maybe induce fox tailing (doesn't look like that at all). The top bud looks dank

personally I don't go by trichomes. They can change back and forth every day. I watch and wait for the hairs to recede into the calyx. Then the calyx will swell 2-4 times over a couple days at that point. Then done. What ever works for you. Do that.

 

[smokey the cat]

Definitely not heatstress - plenty of fresh air and low temp light.


Here's the plant that's still going.Hope y'all envious of the saw tooth leaves and crispy tips. Still getting fresh pistil explosions and the bud is swelling in ways I didn't see it do under fluro lol.

But damn - to much light. It's a thing.

 

[Greengenes707]

I would say that's late flower ripening... Resin tacos of sort.

But ya, too much light is a thing.

 

[Observe & Report]

Right now I'm vegging five seedlings about 10" under a 4kK Vero 18 driven by a MW LPF-60D-36, about 50W at the plug. Directly under the light at 10" I'm only measuring about 500 umol of PPF. 800 umol is about 6" away.

 

[SupraSPL]

Yep no worries. The ladies will sacrifice their leaves at the end that is a good sign.

 

[SupraSPL]

O&R I would not trust those measurements for quantitative but could be useful for qualitative.

 

[Scotch089]

Low Relative Humidity

(transpiration)

 

[smokey the cat]

Interesting range of responses. I've been doing a range of reading to try and find more info too.


Only change is lamp output at around 50-60% of previous for a couple of days.Things are now back on target and improving -

Looking down at the top of a cola - the tissue has re-greened and begun to expand.


I think I was pushing things too far, and then adding mylar totally blew my plants away. The cabinet is a lot brighter - it's almost like putting your plants inside a damn parabolic reflector.

Green leaves after 2 days of mylar:

My reading is that too much light can result in very thick leaves, buds being thin and lacking bulk, and much decreased potency.

This was evident in my last grow, and is also evident in this one.


This thread has a poster describing similar symptoms I noticed on this grow - appearance of apparent sulfur deficiency in veg. Actual problem being blackstar240 too close.
http://boards.cannabis.com/basic-growing/201162-leds-light-bleaching.html

Right now I'm vegging five seedlings about 10" under a 4kK Vero 18 driven by a MW LPF-60D-36, about 50W at the plug. Directly under the light at 10" I'm only measuring about 500 umol of PPF. 800 umol is about 6" away.

Just keep an eye on em Observe & Report mate - those leaf edges will clue you in. Same driver as me - was the 3500k v18 that did most of my damage.
*Possibly a reflection of poor plant condition struggling with the light too. Some reading I've done has pointed to LEDs exacerbating plants with insufficient iron.

 

[MrFlux]

*Possibly a reflection of poor plant condition struggling with the light too. Some reading I've done has pointed to LEDs exacerbating plants with insufficient iron.

Yeah probably the higher metabolism from the higher light level exposes some sort of underlying deficiency. Something is becoming rate limiting.

 

[Mellodrama]

smokey, I read your link in Post #11 all the way thru - it appeared that the involved parties developed a theory it might be an iron deficiency that was exacerbated by the Blackstar. Not the distance of the light per se, but something about the Blackstar's spectrum that caused the plants to use up the available iron, then decline?

I'm a newb. First indoor grow. XGS190. FFOF. Two plants, same strain, 1.5 months old, recently moved from 3 gallon fabric pots to 10 gallon fabric pots. New growth has that exact same pattern of yellowing toward the center of leaves as pictured by Hataman in Post #4. It kind of looks like sulfur deficiency to me, but I don't think it's that simple. One plant is worse than the other.

 

[Scotch089]

"When leaves curl at the tips and margins the plant is trying to retain moisture. When they up this is would be due to an environmental problem rather than a nutrient problem. This could either be due to wind burn, or the lights to close, or not enough air exchange or a combination of all three. I may well be the light is too close for the stage of growth, size of plant or specific variety. Some plants are more sensitive than others."

"Transpiration damage on leaves is caused by too much light and heat. In its attempts to keep cool the plant over transpires moisture from its stomata. In this case the leaf may immediately look a bit blotchy and have lost it shiny, thick, smooth green look for a few days and then start to loose colour generally and especially between the leaf veins..."

"This is a common problem in the summer when using oscillating fans indoors, you have to be careful not to blow too hard on the top surface of the leaf where there is a lot of light or you can draw too much moisture from the leaf and it will at first start to curl up at the tip and margins slightly in an attempt to retain moisture.."

Just from that article, if you have a very "arid" climate they may be transpiring at a quicker rate than what the environment is supporting, along with high levels of light that's a bad combo...


Plant Body Language

 

[smokey the cat]

smokey, I read your link in Post #11 all the way thru - it appeared that the involved parties developed a theory it might be an iron deficiency that was exacerbated by the Blackstar. Not the distance of the light per se, but something about the Blackstar's spectrum that caused the plants to use up the available iron, then decline?

I'm a newb. First indoor grow. XGS190. FFOF. Two plants, same strain, 1.5 months old, recently moved from 3 gallon fabric pots to 10 gallon fabric pots. New growth has that exact same pattern of yellowing toward the center of leaves as pictured by Hataman in Post #4. It kind of looks like sulfur deficiency to me, but I don't think it's that simple. One plant is worse than the other.

hey Mello,

Only concrete piece of advice I can give you is to not to suddenly install any reflective surfaces nearby lol. My plants also exhibited that sulfur lightening ontop the new growth - but things grew ok until I added even more light, which was near-fatal. I dosed with epsom repeatedly, where I normally wouldn't.

The similarity we have is growing in soil - I use a pretty lightly fertilised generic mix as my plants are light feeders. Understand ffof should be more than enough to meet most plant nutrition needs.

Interesting post here - http://boards.cannabis.com/basic-growing/201162-leds-light-bleaching-2.html#post2225087
recommending targeting iron only for supplements - not sure if I've posted this already soz.

I can totally believe that plants in hydro will have bigger pipes internally to funnel necessary nutrition and fuel around the plant. Interesting that this led-related deficiency is showing up for soil growers.

Let us know how your clones turn out. Interested to hear if you give iron a go.

 

[smokey the cat]

"When leaves curl at the tips and margins the plant is trying to retain moisture...

Plant Body Language

That's a great read Scotch

- I can totally believe that different strains will cope differently, with over-bright light. Mandala praised this as a plant good for growers with low light levels which how I've been running it for about 5 years now with fluro.

My leaf margin up-curl definitely wasn't directly water or ventilation related, per se - but I think that link's guess is right: too much light causes stomata to open, leading to over-transpiration, tissue dehydration and damage.

Possibly increasing humidity or reducing airflow over the leaves could have helped the plant cope better too - lowering transpiration losses couldn't hurt.

 

[Mellodrama]

Hey there, smokes, we're from seed, not clones.

The link you provided in Post #15 is the same link you gave earlier in Post #11. That thread got me talking with my better half about iron. We had some chelated iron laying around that had done wonders for some chlorotic looking rhodies in our yard so we mixed up a little bit and dosed the two girls. I used it as a foliar spray on the rhodies but we just added it to the soil for the mj plants. From what I've read it's hard to send mj into iron toxicity so figured what the hey.

I'd been experimenting with a couple of very bright DIY COB's the last couple of days so we're leaving those off for now and relying on just the XGS190 at veg power (130W). The girls haven't given any obvious signals that they want more light so I figured trying to force things might be doing more harm than good.

I wouldn't expect the iron to show up for a few days if it does anything at all. Will report back.

 

[smokey the cat]

Just done a bunch of reading on yellow Rhodos thanks to you haha. I loathe ornamental plants, but I have a bunch of rhodo collectors in my family and it's the done thing to just nod and smile whenever they come up in conversation.

Interesting to make the connection with light use in weed cultivation.

PDF http://cals.arizona.edu/pubs/garden/az1415.pdf -- this was a good backgrounder on iron deficiency and treatment in the domestic garden. Chelated Iron is one of those boxes of nutrients I've seen but never understood why anyone would care to use,so this shit was all new to me.

Really fascinating experiment you've got going there.

 

[MrFlux]

Just remembered that you posted this pic of your plant over a month ago:

View attachment 3018560

That food container looks mighty small, could it just be an undersized rootball bottlenecking your flowers.

 

[WDIK]

Not sure when they went into flower - lol, but I'd guess day 54-56.

Decided to cut the plant last night to avoid any last minute stress-bananas. Trichs 80% cloudy, 15% clear and 5% amber - just a few days short of where it should be. The leaves turned an awesome black colour tho - absolutely stunning.

Other plant has less damage and is still going. It's running a few days behind the chopped plant - I'll give it one more week under half the previous light.


Vero 18 at 50W - stay at least a foot from emitter. Maybe 2. There was some light damage from Vero with cream walls - but when I retrofitted the cab with mylar my plants blacked like a bruised ripe banana overnight.

You may have mentioned in another thread, but how many Vero 18s are you running per plant or square foot?