Plant problems 1st week of 12/12 w/ pics..help!

[Seed Buyer]

We are recently having a reoccurring problem. Plants are going into 12/12 super healthy. Then they start yellowing from the top within a week. My thoughts were heat or a micro nute deficiency. We switched out the (6) 1000 HPS for (9) 600 HPS lights. The hoods are at least 3 ft above the canopy. A 4.0 ton ac unit keeps the room at 77 degrees. Humidity never goes above 50%. The plants are in Pro Mix BX and are feed Iguana Juice bloom from Advanced Nutes pH 6.3. We are also spraying w/ Advanced Revive to try and fix the problem (thought it was an iron or zinc issue) but it had not resolved the problem. Medium pH is 6.5. Any ideas? Thanks

 

[B.C.]

The light is too close.

The light is too close.

Looks like light burn ta me,esp since the rest of the plant looks fine.Are ya usein air cooled hoods? BC

 

[Seed Buyer]

The lights are not air cooled. However, we have run severely crops before this using 1000 HPS w/ the lights 1.5-2 ft away w/ out burning. The 1st action we took was to swap out the 1000's for 600's and add these new "heat diffusers" from Sunlight Supply. The 600's are now at least 3ft (possible more) away from the plants. I have never had a problem w/ 600's burning this far away.

 

[B.C.]

hhmmm

hhmmm

You have me at a loss,I'm not sure what a "heat diffuser" is? But it sure looks like burn to me.The bottom of the plants are purdy much uneffected right? BC

 

[Seed Buyer]

But doesn't micro nute deficiency (iron, zinc) affect the top newer growth 1st? Notice how th etips are turning brown and dying. Would that happen w/ light burn? The diffuser goes under the lamp and is supposed to diffuse the heat so there are no hot spots.

 

[SinsemillaJones]

Looks like good ole magnesium def. to me.

 

[B.C.]

Ya,it'll fry the tips,then the whole leave.Folliar spraying/feedin should have taken care of any def.Btw you did it when the lights first came on right? If ya didn't it will only add ta the burn problem.I think ya need some fans blowin in between the plants and the lights,whiskin the heat away.I gotta go right now,but I'll hollar at cha when I get back.Hang in there we'll getter figured out. Later,BC

 

[Seed Buyer]

We have oscillating fans galore blowing on the canopy and some trained on the hoods. We have been spraying w/ a Revive (micro nutrient) spray and it is not acting very fast. Really stumped on this one!

 

[Seed Buyer]

Forgot to mention we spray w/ the HID off and we add Penetrator to the mix.

 

[Core]

notting of the above ....you have nutrient lockout my friend...
you're ph is 2 high....pro mix BX is soiless and that needs a ph of 5.8 and 6.2...

 

[Seed Buyer]

I have been using Pro-Mix for some time and have always had great results running the pH @ 6.3, also wouldn't the foliar regime fixed the lockout/deficiency issue? We have been flushing w/ plain H20 @ 6.3 in case it was a lockout issue, but it doesn't seem to be helping!

 

[Blackvelvet]

Optimum ph in promix is 5.6 to 6.2

 

[B.C.]

I think if it was a ph issue it would have happen long before flower, also it looks like none of the rest of the plant is bein affected (the bottom).PH would affect the whole plant as would a def.A def might start with the new growth but before they got ta this point (the top half) the rest of the plant would be showin it also.Besides the foliar feed should have taken care of a def anyway esp usein penetrator.I still think it's a radiant heat issue from the light bein too close.Make sure yer fans are on the floor blowin upwards and across,but not on the plants at all,or try raisin the lights fer a few days jus ta see if that's it.Good luck,let us know if it works...Later BC