HELP... Yellow Leaf Edges! Potassium deficiency?

[steeltownstoner]

So i noticed the first signs of DRAMATIC leaf colour change yesterday on two of my Mystery Seed/Juicy G plants. My inital reaction was that the 42w CFL bulbs i am using are too close to the plants and burning the leaves, but this discolouration effect only happened on 2 of my 8 plants and of those two only one or two lower leaves were affected.

To compensate i raised the lights another 4" from the plants, but when i returned today the yellowing edges have carried to another set of lower leaves on the same plant! I would usually reference my grow guide, but its currently on loan to a friend.

If this were a potassium deficiency over fert burn wouldn't all of my plants be showing signs of this? I have 4 Jack Herer plants that have not shown any signs of discolouration...

What could be causing this? Any remedy suggestions?

In the meantime... i'll be reading endless threads till i find out...

Thanks.

http://i494.photobucket.com/albums/r...r/IMG00608.jpg

http://i494.photobucket.com/albums/r...r/IMG00610.jpg

steeltownstoner Reviewed by steeltownstoner on 11-07-2008. HELP... Yellow Leaf Edges! Potassium deficiency? So i noticed the first signs of DRAMATIC leaf colour change yesterday on two of my Mystery Seed/Juicy G plants. My inital reaction was that the 42w CFL bulbs i am using are too close to the plants and burning the leaves, but this discolouration effect only happened on 2 of my 8 plants and of those two only one or two lower leaves were affected. To compensate i raised the lights another 4" from the plants, but when i returned today the yellowing edges have carried to another set of lower Rating: 5

[Rusty Trichome]

You're going to need to fill-out the Troubleshooting Form at the top of the Plant Problems section. Copy and paste the form, and give all the answers asked for, if they apply. Pictures would help, too.

[stinkyattic]

Pics showing the whole plant, and its pot, less blurry, in better light.
Looks so far like overfert but you gotta give some info. That's not a straight K def.

[steeltownstoner]

So i noticed the first signs of DRAMATIC leaf colour change yesterday on two of my Mystery Seed/Juicy G plants. My inital reaction was that the 42w CFL bulbs i am using are too close to the plants and burning the leaves, but this discolouration effect only happened on 2 of my 8 plants and of those two only one or two lower leaves were affected.

To compensate i raised the lights another 4" from the plants, but when i returned today the yellowing edges have carried to another set of lower leaves on the same plant! I would usually reference my grow guide, but its currently on loan to a friend.

If this were a potassium deficiency over fert burn wouldn't all of my plants be showing signs of this? I have 4 Jack Herer plants that have not shown any signs of discolouration...

What could be causing this? Any remedy suggestions?

In the meantime... i'll be reading endless threads till i find out...

Thanks.


http://i494.photobucket.com/albums/r...r/IMG00610.jpg

[stinkyattic]

One thread per topic please. Merged. Not K def.

[steeltownstoner]

Hey Stinky/ Rusty,

Yeah, sorry about the carry over from my log, figured it might help if anyone was following my progress there.


H=Answer if you grow hydro or aero
C=Answer if you grow coco
S=Answer if you grow traditional soil
L=Answer if you grow soilless other than coco (Promix, Hyponex, SunshineMix)
R=Answer if you grow in RockWool
T=Answer if you grow in HydroTon
D=Answer if you run any type of automatic drip system, including into soil or soilless
E= EVERYONE needs to answer lol!


E-indoor
E-hydroponic
E- rockwool cubes, 4"
CSL- Fibrgro
HCL-Ebb & Flow table
SCL- N/A
SCLR- 6.5 pH
E- Tap water in black rubbermaid res
E-7 to 8 pH
HRT-Source water EC (if hydro) (??? - not sure what this means)
E- 25 days in veg
E-Dutch Nutrient Formula Grow A + B (seperate bottles)
E- 1 mL each A & B to approx. 20 L of res water ( 20 mL total of each)
E-4 x 42w CFL bulbs (2 x 5600k, 2 x 4100k), distance from plant 4-6"
E- 88 F during light cycle, 68.5F during night
HD-Room Temperature (approx 71.6f)
E-70% RH
E-18/6
E-Pillar fan suspended from roof of frame, loose cover opening in rear to allow for air intake without daylight coming in
TR- Yes, all cubes were presoaked in pH balanced water before sowing seeds

[steeltownstoner]

opps, think i filled out more than i was suppose to. Definitely need to learn to read instructions next time... :jointsmile:

[steeltownstoner]

Both Plants - http://i494.photobucket.com/albums/r...r/IMG00612.jpg

Plant #1 - http://i494.photobucket.com/albums/r...r/IMG00613.jpg

Plant #1 - http://i494.photobucket.com/albums/r...r/IMG00614.jpg

Plant #1 - http://i494.photobucket.com/albums/r...r/IMG00615.jpg

Plant #2 - http://i494.photobucket.com/albums/r...r/IMG00616.jpg

Plant #2 - http://i494.photobucket.com/albums/r...r/IMG00617.jpg

Plant #2 - http://i494.photobucket.com/albums/r...r/IMG00618.jpg

Plant #2 - http://i494.photobucket.com/albums/r...r/IMG00619.jpg

[Rusty Trichome]

Sorry, I'm not a hydro guy.

Just a guess...but possibly too high ph, and slight overnute...?
What's your nutrient schedule?
Temp swing is marginal. If possible, keep within about 15 degrees f. high/low. The wider the swing, the more it can stress the ladies.
Do you use any other additives, sprays, goops or gels? (micronutes, CalMag Plus, Liquid Light...)

Again, I'm a soil guy, but answering these may help others to help you.

Good luck.

Edit:
I just saw your pix...and nothing looks at all drastic. Matter of fact...they look pretty good so far. :thumbsup:

[stinkyattic]

pH way too high. EC unknown- you need to read the chemistry link in my sig a couple times through. It says 'soil chem' but relates to water chem.
Correct pH for hydro is centered at about 5.8-6.0