Two Weeks Flower...HELP!! (Pics)

[Ncogneato]

Here's the deal:
NRS AK48
Flowering for 17 days
1000w HPS
3 gallon BOG mix soil w/lime
Temps between 72-82 degrees
Ventilation-Strong
Relative Humidity; unknown but definately on the low side
Using R.O. water
Feeding Fox Farm Tiger Bloom and Big Bloom according to schedule at half strength every other watering
Feeding Liquid Karma and Cal-Mag plus every other watering
Runoff PH - 6.5

I am currently running 9 cloned ak48. These symptoms are present on 8 of my girls. My nineth girl has none of the symptoms in question. My nineth girl is also my "guiniea pig" plant. I have been feeding her the exact same nutes as the other 8, only at almost full strength. Obviously, this leads me to believe that my problems are definately a deficiency of some sort. So please take a look at my girls and help me solve my problems.

The necrotic patches on the leaf edges appeared within a week and all started out as shiny spots which turned brown after a day or two. This is effecting the middle and bottom leaves only. I have had this problem with previous grows and it only gets much much worse until the whole plant stops growing alltogether. I believe this deficiency has cost me tons on final harvest weight and quality. Check it out.
Here are my girls at Day 17 flower.







Thanks for your help.
-Ncogneato

 

[sproutco]

At what rate did you add dolomite lime to the soil? How long ago since you repotted? How much cal mag plus per gallon are you using?

 

[Ncogneato]

Dolomite Lime: 2tblsp/gal of mix
Repotted one week before flower - three weeks ago
I use Cal-Mag+ @1teaspoon/gal. R.O. water - applied every other watering

 

[sproutco]

Too much lime then your adding cal mag plus. Runoff ph is on the high side = less uptake of potassium and more calcium/magnesium. I think you got a potassium deficiency. You can easily add more potassium by using potassium nitrate. Try 3/4 teaspoon KNO3 per gallon of water. This would be about 400ppm k. Potassium nitrate is the ingredient in some stump removers at hardware stores. Dexol and green light are two brands but there are others. Just check the label for ingredients.

 

[Ncogneato]

Ahhh, yes, Potassium was exactly what I was thinking......I just wanted to hear it from someone else. I have also heard that low humidity causes a higher transperation rate; in turn causing a potassium deficiency. I would love to hear the theory behind that. Anyway, I already picked up a gallon of Meta-K. Do you think I should back off on the Cal-Mag? Thanks
-Ncogneato

 

[sproutco]

Corrective dose of meta k 0-0-10 would be 18 ml per gallon of water = 400 ppm k. This is quite a bit but won't harm the plant. Stop the cal mag plus. Watch for signs of magnesium deficiency. Apply epsom salts if this happens.

 

[Ncogneato]

vBulletin Message
You must spread some Reputation around before giving it to sproutco again.

Thank you brother Sproutco.......k++