Does a Hps Burn Plants When The Bulb is Bad?

[Irotas]

Hi, I was just wondering if anyone had experienced the tops of their plant yellowing when the bulb is bad, I have never experienced this before. The temperature is fine at 75 so I don't get what's going on.
I left them under the hps after switching from an MH for a night and this is what happened.

I was thinking maybe the bulb is putting out the wrong type of light.

 

[stoned-trout]

no but light bleaching can happen if too close....yeehaw...what wattage light,,, and how close to tops is it??????

 

[Al Botross]

18" - 24" inches away from top of plants as ST said above.

 

[Irotas]

Double post.

 

[Irotas]

I only had it set to 300, and it was like a foot away. I know what light bleaching is. My exhaust is fine as well, so I don't understand what's happening. I even made sure the tops weren't overheating with my hand. They act like it's heat related but it's not hot at all.

Only other thing I can think of is low humidity but the tops are dropping after being under the hps for a day, and I have never had that problem with low humidity.

 

[Al Botross]

As part of growing , maybe bad bulb, replace it immediately and check out the bad bulb later

 

[lawlrus]

If anything it seems like a "bad bulb" would cause less of an issue with bleaching, not more of one. Even with perfect canopy temps you can bleach shit from a foot away with a 400-600w bulb, a 1000w bulb could easily bleach tops that are 1-1.5 feet away. You need to do the cost/benefit analysis to determine where the best place to put the bulb is to maximize penetration while minimizing light bleaching.