Yellowing leaves from too much light?

[ur420ducks]

So today I noticed that the plants directly under my lights have yellowed leaves compared to the ones slightly to the sides. I'm in week 2 of flowering and I am running ebb and flow in smart pot, pure canna coco, ro water with calmag added and full hg nute line. I had a slight mg def last week but upping the calmag fixed it, and now the only yellowing is directly under lights but these plants are still just as tall and have very tight internods. My thought is that with more light the metabolize more nutes causing this yellowingx. If any on has ideas I'd love to know as I am considering rearanging my lights but if I dnt have to I'd rather not mess with em till they are done

 

[Harinama]

what light setup?
how close is the canopy?
what plants?
what nutes?

very possible that it is light bleaching, esp if the leaves look fine and not showing other deficiencies. Generally this happens if plants are <6" from a 400w, or <10" from a 1kw, so if your plants are farther away, you've got other problems most likely. Did you apply veg nutes when you put into bloom? That for me gives them enough N to make it 1/2 way into budding before turning yellow.

 

[HUGE]

I notice this aswell. And had the same theory of that area being overworked.

 

[Cheeb]

I get the same.

I figured it to be that the plants directly under the lights are getting the most intense light possible thus requiring more food then the ones near the edges which are receiving less light.

I always have more lime colored leaves directly under my hoods...

You could try slightly increasing your nutes, but watch for signs of burn.

 

[buddin_904]

yea give em more nitrogen or raise the light a bit....or do a slight combonation of both should fix them up....some people like to put there light too dam close...are you doing this??? lol you can get away with many inches between the bulb and canopy.....to increase penetration try defolation of the upper canopy fan leaves.....this way your light doesnt have 2 be soooo close.....i dont no if thats your problem or not but just throwin a few ideas out there.....

 

[Justin_Credible]

what light setup?
how close is the canopy?
what plants?
what nutes?

very possible that it is light bleaching, esp if the leaves look fine and not showing other deficiencies. Generally this happens if plants are <6" from a 400w, or <10" from a 1kw, so if your plants are farther away, you've got other problems most likely. Did you apply veg nutes when you put into bloom? That for me gives them enough N to make it 1/2 way into budding before turning yellow.

B4 really being able to answer ur question we need the info about wattage and more so, HOW CLOSE to the plant are the lights. I usually keep the 1k's about 12-14 inches above plant. U say u don't want to mess with ur lights? Do you mean u have them set up so u cannot raise and lower them? I have mine on chains for this purpose. Lastly, IMOE it not wise to play with nitrogen once in flower...J.C. try to cut most of it out by the time week two of flower done.
Good luck with it.

 

[buddin_904]

B4 really being able to answer ur question we need the info about wattage and more so, HOW CLOSE to the plant are the lights. I usually keep the 1k's about 12-14 inches above plant. U say u don't want to mess with ur lights? Do you mean u have them set up so u cannot raise and lower them? I have mine on chains for this purpose. Lastly, IMOE it not wise to play with nitrogen once in flower...J.C. try to cut most of it out by the time week two of flower done.
Good luck with it.

you cut your N at week 2 of flower??? wtf man?? that sounds insane....i think 99% of people here would have severe defieciency by week 4 and probably dead by week 6.......

 

[Cheeb]

There are actually lots of people that follow Head's formula using micro 6/bloom 9 which cut out the Micro completely after flower onset or somewhere there after. Not sure if it affects yield negatively or not, but the people doing this are doing so for quality purposes.

The goal is to cut the Micro early enough to leave you with a completely Nitrogen depleted plant come harvest time. This may vary strain to strain as to when to cut the nitrogen completely.

I personally run Head at 6/9 but have never cut the micro out as some suggest. I just run 6/9 until its time to flush and then run straight RO. My plants typically "pale out" enough as I never experience any harshness in my smoke and have no complaints on the way it tastes, burns, ect.

I am interested in it however...as well as if I should increase nutrient slightly when the plants directly under the light start to go lime colored. Thus far I have been just letting it ride.

 

[bu11dog]

Back off with the lights and swap the plants around regularly if possible.

Peace

 

[el dub]

Too hot under the lights for the plants closest to the bulb.

lw

 

[Cheeb]

Its not heat in my experience - intensity yes - but not heat.

Temps are 72 under my lamps right now and I still get more yellowing in the middle then around the edges.

I think its a matter of the plants directly under the bulbs wanting more nutes.

 

[imadoofus]

typically, nitrogen starved plants yellow from the bottom up. ever looked at pics of someone flushing their grow? vice versa- nitrogen burn starts at the last node and works its way down.

light bleaching doesnt turn the entire leaf yellow- it leaches the color out it irregular patterns, leaving white/ greyish splotches. i dont know whats causing the discolorization, definitely not too much light.

 

[whodare]

regardless of the slight yellowing everything still looks great. just read through another of your threads and it was great. i saw you had a problem with air leaks. not sure if its still an issue but i use the foil duct tape to seal all my duct work.

 

[Cheeb]

Thanks!

Just wanted to make mention that this is not MY thread (ur420ducks created it). I merely experience the same thing at times so thought I'd throw up a picture.

 

[designated]

I experience this too both in my organic grows and coco (canna). I've tried increasing the nutrients and backing of the lights. My 600w, ushio bulb with silverstar air-cooled are usually up 2.5-3 feet above the plants. I'm pretty sure its the reflector focusing the light and causing vapor pressure issues in the affected leaves.

The answer I am working toward is a sealed room with adjustawings...should have 32 silverstars up for sale soon.

Thanks for everyones info

 

[dunkydunk]

I get the same thing running two 600's side by side. The yellowing corresponds directly to the 'hot spots' in the reflectors. You can either back off the light to spread out the hot spot, or let it ride. So long as the the leaves just yellow but don't get crispy, I haven't noticed any terribly adverse effects. I work in a pretty tight space, so my plants often get closer to the lights than I like.

 

[cravedog]

I definitely get some light bleaching when my plants are too close to the lights. That happens when my plants go closer then 6 inches to my 1k light.

 

[scurred]

Has anyone tried using one of the oversized reflectors? I am about to purchase a 600 or 1000 and will be using a "Big Kahuna" reflector with it. It spreads the light better because the reflector is double the size of normal ones, I think it's 33" x 27" or something like that.

 

[grapeman]

When in my hydro grow I was able to keep the lights lower resulting in more usable radiation and the plants loved it. In my soil grows, I've found that the lights need to be raised a bit more as the plants cannot assimilate all the usable radiation and keep up with the nutrients needed for balanced health of the plant. I already use the most balanced reflector available, the Magnum XXXL. 3 XXXL units above a 4' x 8' table. Even then, there are a couple of hot spots.

Simply raising the lights will bring balance back to your garden. Adding more nutes IMO will not, since you have already max'ed out the performance of your roots in the soil or coco medium (plants can assimilate more nutes in hydro).

Let nature take it's course. Raise the lights.

 

[dunkydunk]

Has anyone tried using one of the oversized reflectors? I am about to purchase a 600 or 1000 and will be using a "Big Kahuna" reflector with it. It spreads the light better because the reflector is double the size of normal ones, I think it's 33" x 27" or something like that.

I just bought 3 more 600 watters and 3 8" SuperSun reflectors. The SuperSuns are much bigger than my old reflectors, and they don't seem to cast any hot spots, but I don't have any plants under them yet, so time will tell.