Blackened leaves, wilting and drying up - need help - 1st grow

I need advise. 1st grow and been in veg for the past 8 weeks.
Trying out the "sea of green method" (clipping tips to branch out like rain deer antlers) I have had already trouble with nute lock up which I flushed and seemed to recover except two of the plant strands "purps". The two "purps: don't absorb as much water as the rest.
THen they got hit with heat stress from 2 week heatwave where temp got as high as 99 to 120 (cool down method - water mister on timer 3 times per day for 2 minute intervals).
Temp in the closet is normally anywhere from 20% to 50% humidity and temp ranges from anywhere from 60 at night to 75 or 85 with lights on average.

I have the following set up;
Closet: 2 deep x4 wide x 6 high
Main light: one 400w MH (interchangable ballast to 400HPS
compliment light: two cfl 2000 lumens each - blue spectrum 40w
6 clones (2 pot of gold, 2 purps, 2 Grape Deisel) in 3 gallon pots
Medium: Fox Farms Ocean Forest soil
Watering: one ever other (in timer for 1 minute)
Fert: once every month (Fox Farms: Grow Big 6-4-4, Tiger Bloom 2-8-4, Bloom Big .01-0.3-0.7)
Pesticide: 1.5 tsp of Neem Oil + 1.5 tsp dishwashing soap + 1 quart of water - once a week.

Problem:
1. Leaves on bottom are turning yellow and drying up {lack of light or nutes?}
2. other leaves have black growth which then turns to dark brown and spread {fear of Mold}
4. the 2 "purps" have gold colored main stem and very thin {is it mold or just hurting since the nute lock up?|
3. Fan leaves get white specs (spots that are about 2 millimeters in diameter) {heat stress?)
4. Leaves curling downward {probably overwatering?}
5. Wilting stems after 2 days without water (lack of water?)

Here are some other pics to show the issues with the leaves.

I don't really see any "blackened" leaves.... The plants looks ok to me.
Looks like you've got a nice system over there.
Be careful not to overwater. :)

THanks for the reply and compliment - much appreciated - spent some time on this little hobbie.
If you see in pic 11 right where the leaves are curling there is a black layer.
This edge ends up drying up then changes color to brown - then fall off
pic 9 - leaves are curling

What is this? I didn;t have a good pic of the white specs - roughly about 10 spereatically. Hopefully I can get a better digital camera.

If the black is mold. What can I do to stop and prevent?
I think the mister on timer caused this wilting blackening. before taking the pics I cut the leaves that had the blackening thinking it would prevent from spreading - then thought of posting.

Also 8 weeks so far. How long till I go from 18-6 to 12-12 light?

Too much water and too much neem oil.
Go back to hand-watering, and lay off the neem. You are suffocating your plants with it, and should be using a MUCH lighter application and frequency.

Thanks for the reply.

I think you might be right with the watering.
How often should these be watered? (i.e. every 3 days, once a week?)
There are two "purps" that are hurting. Stem doesn't look like it's getting thick and kinda looks weak to me compared to the others.
Also they don't suck up as water as the others do. Any suggestions?

Questions:
1. How often should these be watered?
2. Is is a lost cause for those two?
3. How tall should they be to twitch from 18/6 to 12/12?
:rasta:

Thanks for the previos comment on overwatering - seems to be doing well in that department.

I am noticing issues with the "purps" again.
Main stock on bottom is thin and has barked up - the barking is kind of light gold color (never seens this before).
Problem I see is that the branches that have recovered from the two week heat wave are growing back nicely but thicker - worried that when colas come out it will not support the weight or provide adiquate nutrients.
Seems as though the roots are not picking as much water comare to the others.

Anyone have advise what to do? :wtf:

barking is good. Your plants are strengthening their stalks. The stronger the stalk, the more bud weight it can put on. :thumbsup:

yeah - that I know. But this doesn't seem to be the case with two of the babies. The main stock is not strong and thin. The branches are thicker than the stock.

Is there anything I can do to correct this?
My concern that the stock will not be healthy enough to deliver nute up to the cola when flowering.