Leaves dry, brittle and folding down - HUMIDITY?

This happened after I switched from having the light above the plants to vertically hanging between them. The major difference was in temps and humidity.


Light is 24/0 400w MH
Humidity is 35% - they are in veg.
Temp is about 78F w/ lights ON and 70F with lights OFF.
Feeding with lucas formula and about 2ml/gal calmag and 1 drop/gal superthrive

Plants are in coco. Please help!

UPDATE - here are more details..

I uprooted the plant and the roots look very healthy. In fact, the plant is root bound. It looks small for the size of the rootball.

The waxy coating on the leaves is gone. Not only do they feel dry and thin like paper, but they don't have the usual weed smell. In fact, they kind of smell like button mushrooms (little white edibles). Leaves aren't sticky either.

Would that be wind burn? If so, is that recoverable?

This MH bulb is near a year old now. I have a new HPS for flowering, and wanted to finish up veg with this MH before replacing it. Do older bulbs give out more radiation/UV than newer bulbs?

what about clipping off the damaged leaf, or doing anything to promote new leaf growth? The plant seems stalled for the past 1-2 weeks.

I might try switching to a T5 setup in a few days to see if it makes a difference.

Humidity has been raised to about 55% (from the initial 30%). No difference so far, but its only been 2 days.

If the damage is not recoverable, when should I induce 12/12? At this point, I'd like to harvest and re-do my entire setup. I'll take clones from this plant tonight, from the lower branches.

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UPDATE DEC 27 - Added more pics here:

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bump

Looks like too much N.
If your humidity gets to low, the stomata closes to save waterloss from transpiration, and there by shuts down the CO2 uptake.
It's very easy to overfeed them when that happens, since the growth slows down or stalls completely.

The obvious question, since this started after changing your light config...what is the lateral distance to the light?

I know you have a cooltube...but could it be mild light/heat burn? Is the location of the damaged leaves such that it points at light being too close? Are you rotating the plants?
ET

ok it kinda looks like eagle claw. i had some do the same thing. the odd thing is there was no burns on the leafs. and i was running floresnts at 4inches away. my temps did hit 84f three times in a row but my humity was never below 44% or higher than 52% on average my temps were 70f low 74f high. i treated as heatstress and there was a recovery.so it i was you thats what i would do.

I have since moved the light higher up (been about 3 days). Leaves are still very brittle and dry. Do they recover?

This

If your humidity gets to low, the stomata closes to save waterloss from transpiration, and there by shuts down the CO2 uptake.

Click to expand...

seems plausible. I considered nute burn only briefly before shrugging it off because I didn't increase ppm recently.

the worst leafs never recover.they will recove enough to do there jobs.i do not know how well they do work but i know they will not die off and stay green there just curled and crispwilted. the leafs that had not suffered the most damage and was not real waxie will shape back up some. also another thing could have been heat stress. radiant heat can be just as troublesome looks basicly the same as your plants. 78f is just a temp but we often forget about the heat index. in an atmosphere the heat we feel and the temp are differnt wind plays one role,air exchange is very important.think if you had a bag over your head when the o2 runs out what happens. the plant is the same way with co2 once there is none the air i spent up. so air flow is a must. then think of your self out in the sun on a black top parking lot. the wind isnt blowing at all,so you have the bag over your head.and the humitity is high over 50% so now you cant sweat as well because the water moister is to high. so also transpiration of the plants will decrease so leading to relitive heat stress.

but most of your leafs will recover but they will never be as they was. the new growth will be fine.if the issue was resoved good luck

happy holidays to all

I have some GFxBB and some PPP in the same room with a vert 600. The GFxBB are thriving and the PPP all exhibit these SAME exact traits, if not more severe. They are quite close to the lamp(they're all the same distance from vert 600), and this is all I can attribute to the deficiency because I haven't upped nutes and the environment is pretty ideal.
I guess some plants take better to the close vertical light, opposed to others...

yea very true ricot some plants are more imune to heat than others

i had the same thing happen to one of my plants. i misted it with a spray bottle and kept it away from the light for a few days and it popped back to its perky self within a week... but it could be a different cause

ArcticBlast

if its not prolonged they will completly recover with out much if any signs.

UPDATE - Added more pics to the original post above


I'm not sure if this problem is getting worse or if the plant is improving. I don't notice much new growth. I went vertical again, this time with a smaller fan and with the plants far away so wind isn't constantly blowing on the plants.

Notice in the newer pics the copper colored spots on some leaves. It looks like Ozone damage I've seen in troubleshooting guides, but I'm using no O3 generator.

I water daily, and last 4-5 waterings I have not been giving any nutes. Just pH 5.3 - 5.6 tap water.

i'm no pro, but if its not getting better, cut your watering schedule in half, try misting with a water bottle, or get a humidifier and see if it helps! some plants are just really picky about nutes and water! hope it all works out bro!

ArcticBlast

Thanks ArcticBlast, I'll try cutting down on watering. Weird thing is, a friend who's growing the same seeds (Skunk #1 x Original Haze + SLH) also in coco and using the same nute regimen, and who waters daily, doesn't have this problem. His plants are doing excellent - only diff is he's using fluorescents. Makes me think it's heat stress but I want to be sure.

Also, this problem began when I switched to bigger pots (from 1 gal to 3 gal), but that's around the same time I went vertical.

yeah air exchange is really important too, obviously! i have a very similar problem as you with a couple of my strains...what i've narrowed it down to is poor soil drainage, 0% humidity, and over watering.... lol. So i transplanted, put a wet towel in the cabinet, and cut back on watering every day (just misting if they look like they need it), and many of them bounced back, some of them faster than others!

anyway, i hope you get it all sorted out! i'm sure an experienced helper will be in here soon telling you not to listen to me lol!

take care dude
ArcticBlast

bump - any other opinions?

I am holding off on watering, and in the process of increasing humidity.

Hey !!! Don't listen to arcticblast! j/k
But seriously don't. about the watering.

Do not cut back watering your coco. Water coco every day.
A little chlorosis between veins on the lower leaves from a Mg def. A little browns spotting mostly near the edges, a little tip burn from maybe Ca def. Some bent, clawed and twisting leaves at the top from a Ca def.
Mg starts locking out at pH 5.4 and below.
Lucas formula? modified for coco? 6/9?
If so, flush and finish the flush with your 6/9 mix. Maybe add a bit of Mg.

I'm not saying heat's not part of the problem, but only you can stick your hand by the plants close to the light and feel that.

hazy, it was lucas formula initially, but the last feeding was 6/9. Haven't fed in a week or so though. Wanted to rule off N toxicity.

I'm concerned because I'd like to flower ASAP .. here are more details:

I uprooted the plant and the roots look very healthy. In fact, the plant is root bound. It looks small for the size of the rootball.

The waxy coating on the leaves is gone. Not only do they feel dry and thin like paper, but they don't have the usual weed smell. In fact, they kind of smell like button mushrooms (little white edibles). Leaves aren't sticky either.

Would that be wind burn? If so, is that recoverable?

This MH bulb is near a year old now. I have a new HPS for flowering, and wanted to finish up veg with this MH before replacing it. Do older bulbs give out more radiation/UV than newer bulbs?

what about clipping off the damaged leaf, or doing anything to promote new leaf growth? The plant seems stalled for the past 1-2 weeks.

I might try switching to a T5 setup in a few days to see if it makes a difference.

Humidity has been raised to about 55% (from the initial 30%). No difference so far, but its only been 2 days.

If the damage is not recoverable, when should I induce 12/12? At this point, I'd like to harvest and re-do my entire setup. I'll take clones from this plant tonight, from the lower branches.

4-5 times a day is way too much in coco. Your plants are drowning IMO.

Me too on the over watering. Do you have a moisture meter ? Like $5 at hardware store.
I water coco when its at the border of 'moist' and 'dry'. Thats about once a day for big plants and every other day for small. But I'm posting here with major problems so don't listen to me !