Developing yellow/brown spots & twists in leaves

[KnightRueben]

Hello everyone,

About a 3 days ago, one of my three mexi-brick bagseed plants developed a twisted pair of leaves. The problem seems to have progressed as today I discovered some yellow/brown spots on leaves. Here are some basic facts:

1) Strain: Mexican Brick style bagseed
2) Age: 14 days from germination, all 3
2) Nutrient schedule: NONE, only water @ 6.2 ph, filtered through a filter
3) Watering schedule: every 3 days, letting them dry out completely down to 2'' beneath surface
4) Medium: Fox Farms Ocean Forest cut 40% perlite, 60% soil
5) Light: Vegging under my 150w HPS, no other alternative atm
6) Distance from light: 8'' from canopy to bulb for their whole lives
7) Temperatures: 78-84 (rarely gets that high) F at canopy of plants

So here is a shot of the twisted pair of leaves as they came out, everything else looked healthy then.

http://i538.photobucket.com/albums/ff346/Adriode_2008/Sicks007.jpg

I thought nothing of it, however today I pulled open the box to take a look at them and beheld the development of some yellow/brown spots!

http://i538.photobucket.com/albums/ff346/Adriode_2008/Sicks021.jpg
http://i538.photobucket.com/albums/ff346/Adriode_2008/Sicks020.jpg

That one plant has it the worst, and this literally happened overnight. However there is some slight spot developments on another plant too, that I just transplanted:

http://i538.photobucket.com/albums/ff346/Adriode_2008/Sicks028.jpg

It's hard to make out, but you can see it just as the shade ends on the bottom left leaf.

Finally, my last plant has a new growth that is VERY twisted, as if it is trying to twist and shy away from the light:

http://i538.photobucket.com/albums/ff346/Adriode_2008/Sicks030.jpg

Any help would be largely appreciated.

 

[KnightRueben]

Additional Information as per Instructions

Additional Information as per Instructions

SOIL:

How long has this problem been going on?
1 day

What STRAIN are you growing?
Mexican Brick style bagseed

What was the establishing technique? (seed or clone?)
seed

What is the age of your plants?
14 days from germination

How long have they been in the soil mixture they are in now?
14 days

How Tall are the plants?
6-8''

What PHASE (seedling, vegetative or flower) are the plants in?
vegetative

What Technique are you using? (SOG, SCROG etc)
none at the moment, planned on LST

What size pots are you using? (Include how many subjects to pot)
2 are in solo beer cups
1 has been transplanted recently into a 1 gallon pot

What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
Fox Farms Ocean Forest
Cut at 40% perlite, 60% Soil

What Nutrient's are you using?
NONE at the moment. Only water, filtered thru a water filter @ 6.2 ph

How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
NONE

How often are you feeding?
NONE, but I water about every 3 days when the top 2'' of soil become dry

If flowering, when did you switch over to using Bloom nutrients?
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)
N/A

What is the TDS/EC/PPM of your nutrients used?
N/A

What is the pH of the "RUN-OFF"?
will test tonight

What method of pH test was administered? Using Strips? pH pen?
Strips

How often are you watering?
Every 3 days about, when top 2'' of soil dries

When was your last feeding and how often are you feeding?
n/a

What size bulb are you using?
150w HPS

What is the distance to the canopy?
8'' their whole lives

What is your RH Factor? (Relative Humidity)
41%

What is the canopy temperature?
78-84 F

What is the Day/Night Temp? (Include fluctuation range)
Nighttime is 78-84, daytime is about the same

What is the current Air Flow? (cfm etc.)
Cooled by 130CFM S*P

Tell us about your ventilation, intake exhaust and when its running and not running ?
Running @ ~120 CFM when light is on, about half that with lights out (I use a Variac)

Is the fan blowing directly at plants?
No, intakes rout air around them and get sucked up past the light

Is the grow substrate constantly wet or moist?
Not really, fairly dry on 3rd day

Is your water HARD or SOFT?
Somewhat Hard, filtered through a water filter

What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Tap water, filtered

Are you using water from a water softener?
Yes

Has plant been recently pruned, cloned or pinched?
No

Have any pest chemicals been used? If so what and when?
No

Are plant's infected with pest's?
No

 

[Crush]

The rust spots seem to be a PH problem. Most likely it's too low causing rust spots. Many people believe that it's water getting on the leaves and the heat frying them. Man that must wreck some havoc on plants in nature after it rains I guess.

These soil mixes are acidic so they use dolomite lime to UP the PH because they know home users will be using tap water at 7ph. However, since you are bringing it down to 6.2 that could be a problem. Also, since you have a 40% mix of perlite, you also may need to manually add dolomite lime.

Do a search for you soil in google and there will be tons of discussion on this.

Here's a common someone made regarding fox farm similar to your mix. He's adding more lime although the mix already has some. I find the soil mixes are a bit on the acidic side in general.

"Unlike the above reader, I add 40-50% pearlite and a tablespoon of dolomite lime per gallon of soil." - http://www.icmag.com/ic/showthread.php?threadid=65913&userid=25560

Or you can just consider it growing pains. Jiffy Pellets are very acidic and if they were kept in there too long, that could be a symptom.

 

[KnightRueben]

Crush -

thanks so much. It's greatly appreciated.

So I took your advice and went ahead and checked the runoff PH after a slightly early watering. The PH was in the mid to upper 5's.

I went ahead and bought a 40lb bag of dolomite lime at home depot, the smallest size they had. I transplanted the two left in solo cups into 1 gallon pots with a mix of 40% perlite, 60% fox farms ocean forest with a little more than 1 tablespoon of the lime.

Then I went ahead and gently pulled out the already transplanted one, added a little over 1 tablespoon of the lime, mixed well, and replanted him/her (it's in a 1 gallon pot).

I'll post updates with how things go.

 

[KnightRueben]

Well it's been 24 hours or so, I see no improvement yet - but no worsening.

I've done alot of additional reading about PH levels - can anyone reccomend a FLUSH to get PH up in this situation?

My tap water straight up is at about 7.8. Should I condition that down to about 7.5, let it sit for 24h for chems to evaporate, then perhaps flush with that?

I didn't read many instances of people flushing to get ph UP...but the lime will probably take weeks to correct this imbalance by itself, no?