what's causing this?

[datura_kid]

i had slight changes indicating ph problems, seems like it has been 7.4-7.5 according to my calculations...started fixing it (using destilled water cuz i dont have ppm meter to see hows my tap here, thought it might be too hard and that it might be part of the problem), the plants got better, but just as they did, lower leafs, mostly 3 fingered ones (but also first set - one fingered ones) and mostly middle one of those 3 fingers started getting some thinning patches (pale green) between veins more towards the tip of the leaf, going back as it progresses, and also those patches becoming brownish as it progresses, and finally looks like burnt, leaf is crispy and yellowing of entire leaf is starting...not all of them got this, maybe more then half, but with days it happens on more and more plants...

some info on the net says it could be ph being off, but im in the progress of lowering it (slowly)...i don't know if i do the math right but here's how i meassure it: water with ph 6.5, read the runoff, it comes 6.75, so i guess this would be the middle (between water and soil), and i would estimate that ph is a bit under 7.0. Then i try meassuring with 6.1 and get runoff results from 6.55 to 6.75 (differes from plant to plant). then i tried with 6.3 and got pretty much same results, 6.6-6.7. am i doing it right?


I've fed them once foliary cuz i suspected there might be K and Mg deficiency at one moment, and once with watering last time when i thought ph dropped enough for them to take the nutrients...

they are skunk #1 feminised, 24 days of vegetation from seed in soil, transplanted in 2.6 gal pots after first week, were under 3 x 400w until today when temps dropped enough to turn the 4th light so its 4 x 400 now. temps are under 75 day, 65 night, 30% RH. The plan was to induce flowering after 28 days.

i attached some pics for you to see...some minor and then towards bigger damage...its taken with phone so they are not the best...

 

[datura_kid]

if it's not ph, which i said im lowering and this started happening during lowering, then i could only suspect Mg deficiency, but as i said i foliar fed them epsom salt like week ago cuz the leaves were looking up and after that fed by watering full spectum of nutrients...maybe they do need more Mg? to feed more epsom salt by water of foliar?

 

[3rd base]

datura kid, ya gotta give us more meaningful info...

So your plants have been vegging for about 3 weeks, are in 2.6 gal pots and have been under 1200 watts of light.
You're in soil... what kind of soil? Store-bought or did you follow a recipe? How are you feeding? How often? How are you watering?

The following questionnaire should be completed to help us help you...

How long has this problem been going on?
What STRAIN are you growing?
What was the establishing technique? (seed or clone?)
What is the age of your plants?
How long have they been in the soil mixture they are in now?
How Tall are the plants?
What PHASE (seedling, vegetative or flower) are the plants in?
What Technique are you using? (SOG, SCROG etc)
What size pots are you using? (Include how many subjects to pot)
What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
What Nutrient's are you using?
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
How often are you feeding?
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)
What is the TDS/EC/PPM of your nutrients used?
What is the pH of the "RUN-OFF"?
What method of pH test was administered? Using Strips? pH pen?
How often are you watering?
When was your last feeding and how often are you feeding?
What size bulb are you using?
What is the distance to the canopy?
What is your RH Factor? (Relative Humidity)
What is the canopy temperature?
What is the Day/Night Temp? (Include fluctuation range)
What is the current Air Flow? (cfm etc.)
Tell us about your ventilation, intake exhaust and when its running and not running ?
Is the fan blowing directly at plants?
Is the grow substrate constantly wet or moist?
Is your water HARD or SOFT?
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Are you using water from a water softener?
Has plant been recently pruned, cloned or pinched?
Have any pest chemicals been used? If so what and when?
Are plant's infected with pest's?

I don't follow how you're checking and trying to correct your pH.

The symptoms in your pics could be caused by anything from not watering thoroughly to pH problems and does not look like a Magnesium deficiency.

The more info you give up front, the quicker we can give some meaningful suggestions...

 

[datura_kid]

How long has this problem been going on?
few days

What STRAIN are you growing?
skunk #1 feminised from sensi seed bank

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

What is the age of your plants?
24 days, counting from putting seeds in soil

How long have they been in the soil mixture they are in now?
about 2 weeks

How Tall are the plants?
20 - 30 cm

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

What Technique are you using? (SOG, SCROG etc)
christmas tree

What size pots are you using? (Include how many subjects to pot)
2.6 gal, one plant per pot

What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)
substral terra magma soil (used it few last grows with good results) with added crushed styrofoam (also used it before) instead of perlite

What Nutrient's are you using?
"Compo" 7(3,3% nitrate, 3,7% amonium)-3-6, with all other microelements some of them EDTA, also used epsom salt foliary

How much of each nutrient are you using with how much water? *Knowing the brand is very helpful*
epsom salt foliary once 1/2 teaspoon per liter of water, used COMPO just once 1/2 recommended dosage (doesn't have ml, just sign in cap how much to mix in one liter)


How often are you feeding?
fed just once with watering (few days ago) and once foliary epsom salt

What is the TDS/EC/PPM of your nutrients used?
i dont have PPM meter

What is the pH of the "RUN-OFF"?
i don't know if i do the math right but here's how i meassure it: water with ph 6.5, read the runoff, it comes 6.75, so i guess this would be the middle (between water and soil), and i would estimate that ph is a bit under 7.0. Then i try meassuring with 6.1 and get runoff results from 6.55 to 6.75 (differes from plant to plant). then i tried with 6.3 and got pretty much same results, 6.6-6.7

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

How often are you watering?
usually every second day, until the pots are light

When was your last feeding and how often are you feeding?
2 days ago, that was the only one

What size bulb are you using?
4 x 400 w (1MH, 3 HPS), but it was 3 x 400 until today (1MH, 2 HPS)

What is the distance to the canopy?
50cm

What is your RH Factor? (Relative Humidity)
25-35%

What is the canopy temperature?
82-84F

What is the Day/Night Temp? (Include fluctuation range)
day 70-75, night min shows 62 but till today never was under 65

What is the current Air Flow? (cfm etc.)
1000 m3/h, have 5 stage voltage regulation, as colder weather came i keep it on 2 (110 V of 240 max)

Tell us about your ventilation, intake exhaust and when its running and not running ?
active intake and exhaust, running all the time at daytime, at nighttime i give it 15 min off every 45 min or so

Is the fan blowing directly at plants?
yes, revolving fan blowing at canopy

Is the grow substrate constantly wet or moist?
no

Is your water HARD or SOFT?
dont know
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
was using tap with 8.5ph but after some problems with ph i switched to destilled cuz i thought too much Ca in tap could have locked out Mg (showed signs of leafs going up)

Are you using water from a water softener?
no

Has plant been recently pruned, cloned or pinched?
no

Have any pest chemicals been used? If so what and when?
Are plant's infected with pest's?
no

 

[3rd base]

A few more q's for you, dk...

Your plants are about 25 cm tall or about 10 in. Where on the plant are the affected leaves in your pics? Toward the top, middle, bottom or all over?

How much crushed styrofoam did you add to the soil? Would you say 10%, 30%? (Rule of thumb is about 30% perlite to ensure good drainage. From your pics, it looks like the soil doesn't have enough.)

When you water, do you water slowly so that the soil is thoroughly saturated and there is plenty run-off? (The purpose of this is to ensure there are no dry pockets in the soil.)

 

[datura_kid]

as i described in first post, this started happening on 2nd set (3 finger leafs - middle finger, and slowly appearing on side fingers), then i noticed it lower on first set also (not on all)...

soil has approx. 25-30% of styrofoam in it, but you see less cuz i get a thin layer of just soil over so the vent doesn't blow it around the room (its annoying and it can land on plants sometimes), but there is still some on the surface....but drainage is good, i used this mix few times with good results...only new thing is hydroton i never used before (for drainage), but in stead i used bigger styrofoam pieces (which are also in few pots right now cuz i ran out of hydroton (washed before potting))

yes i water very slowly with bottle that has that sucking pipe (for drinking, if you know what i mean)

im just crazy cuz i never seen such thing before, and cant find anything alike on the net except ph or maybe Mg deficiency. Im thinking of trying epsom salt foliary again...

also can you comment PH meassuring in my first post? is this right calculations?

 

[datura_kid]

i got few pics for you to maybe see better, but dont have camera at the time, and just did those with filthy phone lense (damn)...

and no, those styrofoam chops are not so big in soil, these are drainge ones from beer cups left after transplanting, just left chilling on top of big pots...

 

[3rd base]

Ok. So your soil drainage is good.
You water slowly, but do you keep watering until it runs out the bottom of the pots?
I'm making sure because dry pockets can cause dead spots on leaves, like in your pics.

About this Compo fertilizer... do you know the pH of the mix before you apply it? Since you have a pH pen, you should measure and note the pH of it.

Back to the soil... I apologize my German is not so good, but on the website for the soil, I couldn't tell if there was any added lime... if the pH of the Compo fertilizer is too low (or high) the soil may not be able to correct it.

I cannot comment on your method of measuring the pH because I did not understand it. I believe that if you use a pH pen to measure the run-off and it reads between 6.3 and 6.8 you're good.

I understand that your pics are from your phone, but the plants look healthy otherwise. The brown spots seem to be confined to only one or two leaves on the entire plant. Also from your pics they do not look like they need Mg.

All I can suggest for now is make sure you water thoroughly until there is plenty run-off from the bottom of the pots and make sure the pH of the fertilizer is not too low before feeding.

If I have missed something please let me know...

 

[datura_kid]

yes, i water slowly and i get runoff almost every time (maybe 20-30 ml from 250-400 ml added every second day). i even think few of them might be slightly overwatered cuz they are kinda droppy, but soil is dry before watering and pots are light...

also this round i dont use h2o2 anymore cuz i heard it also kills good bacteria, which i didnt know, and will only use it if needed.

i do ph the water and the mix if feeding to 6.5 usually if everything is ok, but ive been lowering soil ph starting at 6.5 when it was 7.4-7.5, and last time with 6.0 when runoff was 6.55-6.75 (trying to do it slowly not to shock the roots) with destilled water worring that Ca might lockedout Mg from tap water waterings, but then again i saw some slight Ca deficiency on 2 of the plants, and just a bit of fert burn i think on 2.

im not shure about the soil if it has lime (not good with german either lol), but ill check on the bags if it says anything...i heard that it stabilises ph but never acctually encountered such a thing...i used this soil in the past in mix with styrofoam and plus 10% sand (which im not using now) but everything was in order...

acctually this new sealed room, new and better everything, new ph (used paper before), but alot of bad things happening...started with mildew which i never had before (but i believe it was my mistake letting %RH go high with low ventilation setting thinking they were just babies they don't need that much fresh air), then this which i never ever saw, or even see same simptom on the net, and now just half an hour ago i see what i believe it is the beggining of spidermites on few plants, which you can guess i never ever saw before...things seemed to be better when it was ghetto =) and i even change clothes when entering the room, wash hands like a doctor before operation...aldo it is just eggs that i saw (few) and 1 piece of like 1/2 inch of net or string to be exacly...but didnt see any moving creatures up or under leafs...i check them throughly once a day...

all right enough rambling...gotta go mix something natural to kill the bastards...


and dude, forgot to say, but i really appreciate your time

 

[3rd base]

You're welcome, bro. (I'm just trying to help out in the infirmary to get my post count up.)

Spider mites?! I've never had them, but I think they suck the juices from the leaves, leaving dead brown spots behind...

Neem oil and insecticidal soap can kill them, but I think you have to spray the plants every day for 2 weeks (or until they're dead).

Best of luck with everything.

 

[datura_kid]

yes this is crazy, never saw a spidermite in my "career" (aldo not so long career) and now that i have sealed room and really watch out for hygiene they are here...they've been around for some time but i was foolish enough to think their eggs are just some leaf hairs...i checked my babies throughly and i know mites are tiny but didnt see one moving thing, and people say they are roaming around...

i sprayed them with detergent/oil mix 2 days ago and just bought insecticide "KARATE ZEON" with lambda-cihalotrin as active ingridient because i couldnt find any of here recommended products liek floramite, avid, azamax or alike, and dude in store recommended this, he says it has really wide spectrum and does not harm the plant, and its hard stuff i guess cuz its mixing 1 ml per 10 L of water.

anyhow i thought that this problem with leafs might be spidermite related (i saw some small cracks, holes, cuts that is most probably eaten by mites). And those lower 3 finger fan leafs that were earlier "infected" are now almost completly yellow...