All new growth is VERY yellow, could it be too old bulb??

[iceman1027]

All my new growth is coming in very yellow. The bulb (400w HPS) I bought with the lamp (used) and didnt buy a new one, I just switched from the MH to HPS for flower and now growth has slowed significantly and the new growth is yellow, could the bulb be past its prime even though it fires up so much that its output is inadaquate? the problem is about the same across all plants.

 

[cellardweller]

funny, I have the same thing going on with a brand new Eye Hort 600w. They are however, growing extremely fast. so I don't know if that has anything to do with it..

 

[iceman1027]

when i had the MH in growth was green and great. i am thinking about putting it back in to see if it fixes the problem, will the change in color spectrum stress the plants while in flower?

 

[cellardweller]

maybe because you had mixed spectrum light at first they were still light green and you couldn't see it as well?(or did ya look at em in regular light too?) or maybe since you took away the blue spectrum it's affecting them somehow? I don't know if adding or taking away blue light would stress em...I'm thinking no, but I really have no basis for why I am thinkin it. Looks like time for some search function action..
Once I get a few minutes and some ambition, I'm adding 160w blue floros to my 600w as I believe it does add density later in flower.
peacenpot,
~cd

 

[ibjamming]

Are you judging this because of how they look under the HPS? They look yellow in that light. Pick off a piece of a leaf and bring it outside...I bet it's nice and green...

 

[terminalc]

I find that moving a plant from a t5 in veg with no co2 to under a 600w hps w/ co2 with everything else dialed in and transplanting into a bigger pot makes plants turn yellow. I found upping my ec solved the problem in coco. What ec are you feeding?

 

[iceman1027]

It's def not just the color of the bulb because all the older leaves are still green...

As far as I can tell it could be a number of things, too little light? light too close? or nutrient deficiency. though lower leaves are showing signs of low pH so i dont want to add nutes. with i had more experience with all this. i think ill just water with r/o water for a week or two and see what happens. all this micromanaging is killing my plants.

 

[orpanic]

Ok, what I think is going on is a drop between night and day temps, sativa's will usually show this especially since they don't like a big change in temps. Keep the diff less than 10 deg if possible. This usually happens when flipping to flower, which looks like where you are at...Keep it up brother and enjoy your harvest, its the best stuff around~

 

[Muddy Paws]

Is the new growth yellow, or just light colored? This is a sign of vigorous growth in most cases.

It means the plant is growing at too rapid a rate for the chlorophyll to convert the nutes to leaf structure. Your plants are fine.

If the plants are showing good growth than your PH is fine. Those yellow leaves mean it's time for an N feeding.

I wouldn't change a thing you're doing; a pic or two would let me know for sure what's up.

 

[Perpetual Nooch]

Is the new growth yellow, or just light colored? This is a sign of vigorous growth in most cases.

It means the plant is growing at too rapid a rate for the chlorophyll to convert the nutes to leaf structure. Your plants are fine.

If the plants are showing good growth than your PH is fine. Those yellow leaves mean it's time for an N feeding.

I wouldn't change a thing you're doing; a pic or two would let me know for sure what's up.

I agree with Muddy Paws. I've noticed light-coloured new growth when the plants are growing extremely fast. Increase your N and see if that doesn't help.