Urgent help - thin line-colored leaves!

[infoplease]

Hi

It's my first attempt at growing, and I think I'm really in need of sage help at this point. First off, the main reason I'm writing and the relevant photo. See below for more details...

As you can see, the new leaves are thin, yellow and curl a bit. They look bad. Plus, some of the older leaves, mostly but not only near the top, are looking sick with yellow spots.

Again, it's my first time growing. The details are: I have two Northern Lights plants, exactly 8 weeks old. They're ~34 cm tall (13.5 inches). I'm using a bunch of fluorescent lights, day/warm mix, and the temp has been >25 by night and <35 by day (in Fahrenheit it's 77 and 95, and no I can't lower the temp till winter gets into gear). Humidity is steady ~55%. They're growing in soil, and it's not a special mix for weed, so drainage is average at best.

I've been giving them Root Juice, BioGrow and Algaemix, mixing the three liquids into about 2 cups of water and adding a pinch of ph reducer to get the ph from ~7.5 to ~6.0. Then I give them about 2 cups of clean water to wash the roots, followed by the aforementioned mix...

I was very careful not to over-water, so I might have let them go without water (or ferts) for more than a week. Then I noticed the problem, rushed to the internets to see what it might be, saw it might be missing Sulfur, and watered and ferted both. One of them seems to be doing a bit better, but it wasn't as bad as the one in the picture in the first place. The one in the picture is... not ok

(the one not pictured doesn't have many yellow spots, mostly just thin new leaves which are very light green/lime)

Please help...!

 

[infoplease]

In case it's important: I had a whitefly problem, which I've been treating with a "friendly fungus" called Beauveria Bassiana. It was recommended by the local grow shop, you mix 1ml into a liter of water and spray once every 6 days (it says not more).

I did it for three weeks, mixing up a new batch every time, and it wasn't really helping. Back at the store they told me A. spray every 3 days, it's better B. you can use the same batch for a few weeks, don't have to remix and C. whiteflies breed if the soil is wetter than it should be, so wait even longer between waterings.

It's been a few weeks since I followed this latter advice, and the whiteflies are mostly gone. Not sure if it's relevant...

 

[SnowBender]

am i read that right? you only water them with 4 cups of water? I would want more than that in runoff alone. "over watering" is usually not the amount of water but the frequncy that they get wattered. more water less often, is better than less water more often.

How to Ask for Grow Support

Seeing some of those spots would make me look very close for bugs/. (edit: did not see white fly post)

 

[infoplease]

Thanks for the quick reply. I'll start watering with more water, but because I bought the special soil mix weeks after I planted these, my biggest plants for now, I've only been able to use it for a few other pots (not problematic enough to post about at this crisis point). These two are sitting in good but not specialized potting soil, and sometimes after I water they take more than a week to stop being moist - then I get worried :\

As for the whitefies/pests... I'll check very closely as soon as I can, but so far I just assumed I've almost gotten rid of them, because in my daily checkup, when I ruffle the lower leaves, turn them over, and vacuum whoever flies out, I've been seeing less and less of them... Almost none, lately, and no little yellow eggs(?).

 

[infoplease]

Is that link here to imply that I didn't post my question correctly? I'm trying to read thru it, but have limited time today, and thought the plant's condition is rather urgent and that the picture was very indicative... :\

Still, to supplement:

Strain - Northern Lights
# of Plants - 2 females
Grow Type - soil
Grow Stage - veg, week 9
Setup - manual watering
Light - ~250w worth of CFL, half "daylight" half "white light"
Nutrients - BioBizz products, currently mostly Bio-Grow and Alg-a-mic
Medium - Potting soil (no vermiculite, not great drainage)
PPM - (what's ppm?)
PH - ~6 (from ~7, after adding some reducing powder)
RH - 50% to 55%
Room Temperature - currently 75 to 90 f. (indoors but not basement so fluctuates)
Solution Temperature - ?
Room Square Footage - ~10.5
Pests - Very few whiteflies (after treatment with Beauveria Bassiana)

Problem: See image below or in initial post, new leaves are thin, light green or yellow, curled at the tip. Lots of old big leaves near the top have yellow/dry spots.

BTW the original title should have "lime" instead of "line"...

 

[infoplease]

Well, I looked at the plants again and the pictorial problem solver guide again, and for now I'm working under the assumption that it's a ph imbalance... But then why would it affect one of the plants so much more than the other? And why would it manifest only after 8 weeks of growing or so?

Please, how do I test the soil's ph accurately? I have laboratory ph testing papers.

Also, here are some close ups of what's happening to the big leaves

 

[Kronnoisseur]

Well, I looked at the plants again and the pictorial problem solver guide again, and for now I'm working under the assumption that it's a ph imbalance... But then why would it affect one of the plants so much more than the other? And why would it manifest only after 8 weeks of growing or so?

Please, how do I test the soil's ph accurately? I have laboratory ph testing papers.

Also, here are some close ups of what's happening to the big leaves

Spraying plants frequently and during high light exposure can create problems. Just spray stuff on so the plant doesn't breath as well for awhile too. Next time pick up a bottle of monteray insect control get that stuff done with and it's OMRI listed. Shot off the top of my head, look into calcium and magnesium... I may be far off but that is what I would give them. 6-6.5 is fine for soil pH only have to finely adjust between there for optimal yield.