plant stress response ? or effect of changing light angle question please ?

[Collembola]

hello,

sorry if this is in the wrong section,

i tried reading about paliside cells although unable to yield information on how little the underside photosynthesises vs. the top of leaf and just added another variable into not knowing the answer.

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> i switched from a mh horizontally, to hps vertically, *plants are just showing "proper" pistil developement (i.e. stretch finishing (...i hope!).

the lumens hitting the plants, is exponentially higher, now, major increase (my canopy was uneven).

all plants responded by cupping their leaves (whole leaf structure pointing upwards (not heat releated effect on tips etc, no signs of bleaching etc))

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please could someone answer, baring in mind the plants are recieving exponentially more lumens > will this be a stress response to the increase (*perhaps to protect their flowers ?), or will it probably be because of the light angle change and they are still currently "programmed" to recieve light from above, not the side ?

THANKS for any help.

 

[Phaeton]

A photo would be nice.

Sometimes when a leaf thinks it is getting too much light it will angle itself so less light hits it.
This can be done by cupping, the leaf makes a deep 'V' shape so it is thinner and gets less light.
The leaf can also turn its tips towards the light so less light will hit it.

Other stresses can cause curling which is why a picture is needed.

 

[3rdEye]

can you measure the lumens at the leaf/canopy surface collembola? I'm assuming it a response to the greatly increased light intensity. I have seen this response in some of my plants at times.

phaeton brings up some good points.

 

[Collembola]

thankyou, sorry i sold my old camera to buy a ballast and am in process of saving for new one although i drewed a picture if it can be deciphered ?

it's darkperiodnow, although i am pretty sure it will be recieving 1.5 to 2x the amount of lumens, guessing referencing hps charts in the 80-100,000 range.

(don't know how to read a lumen meter, only to check increase and extent etc (those 3 whole setting are VERY confussing !!!)

they are sativa dominant plants and showing no symptoms of excessive heat / light (baring the potentially massive one i am asking about...) although there is slight over-N now (i have been feeding them heavy after the stretch) at the top of the canopy (although no big solar leaves there to reference)

the leaves are perpendicular, with the under vein pointing foremost to the light, although the ones on the rear, in much shadier conditions and lower in the canopy are are doing it also (i.e. leaf surface pointing directly to the light on the rear).

the tips are errect, following the angle of the leaf major (i.e. if the leaf was horzontal they would be too)

picature:

thanks!!!

 

[3rdEye]

The way the leaves are responding seems to indicate too much light, but i am not sure. Keep us updated. If you can get a picture that would be helpful, but your drawing is good and helpful.

How fast was the change in the leaves?

 

[Miraculous Meds]

Id say stress from light intensity. back the canopy away from the bulb an extra 2 to 4 inches n see if they don't straighten out. The other thing that comes to mind is low rh. The micro climate at the canopy surface around the bare bulbs can be very low rh due to the heat of the bulb. Pretty much have to do the same thing for this. Pulling the canopy back from the intense light should help. Of course measure ur rh to make sure its around vpd range.

 

[Collembola]

thankyou all!!

i dunno really when it started, i think it was pretty quick although i spent a while hardening them off on 250 prior to 400, cannot really remember if they were doing it with 250w output.

they are still showing it, for maybe a week or so now,

i am still a few weeks off buying a camera though ...saving for dslr.

if i turn the ballast down to 250w output (instead of 400w), and the leaves return;

would that pretty much conclusively suggest that its the light ?,

i had considered defoliating the fans on the front 45 degree angle or something but i guess that would have been a BAD idea...

i had not considered RH although i have a fan blowing beneith the bulb, so that would correlate, but the shaded leaves i think RH will be 80 or something guessing, it is a small tent, that tends to get rather humid.

thanks for the help,

 

[EssentialGround]

Measure the light intensity with umols in the 700nm range, plants can only use light in this spectrum range.
So measuring lumens doesnt give you any idea of what your light is putting out that the plant can actually utilize. . .
Also the use of a chlorophyll meter to monitor photosynthesis would be ideal..


EG