new growth dying!!! need help!!!

[jon cooley]

Ok so here's the deats:

- Growing one plant (rascal OG)
- using a grow lab 40 grow tent completely coated in mylar
- ventilation is really good
- temp ranges between 74-78 during light 66-70 at night
- feeding every 2 weeks with 20-20-20 fertilizer
- watering every 48 hrs with 200ml of 6.0 ph water
- using miracle grow moisture control soil


Now the problem, some of my new growth is dying (only on the top) and I'm seeing dark yellow spots on a few of the leaves, any ideas????? Any info is greatly appreciated. Thanks!!!

 

[jon cooley]

Oh and I'm only using 1/4 the recommended amount of fertilizer, so I don't think its over fertilizing

 

[Hemlock]

Raise the light or lower the plant, thats light stress/burn..Notice how nothing on the bottom is burned, you can tell that coming from the outside not the inside.

 

[jon cooley]

Yea that is what I thought too. But I don't understand? I'm using a 100w hps that's 6 inches from the top of the plant. I've done the hand/heat test and the distance seemed fine??

 

[Hemlock]

Yea that is what I thought too. But I don't understand? I'm using a 100w hps that's 6 inches from the top of the plant. I've done the hand/heat test and the distance seemed fine??

Might be the plant was just in a hot spot. But I would still raise it and rotate it everyday for a week or so and see how ya look.
Good Luck