Same Problem AGAIN - Necrotic Spotting (pics)

[Koskesh]

This is the 3rd time I've had this problem, it starts 2 weeks into flowering. I posted a thread here about it, and the general consensus was a PH problem, was told I was using wrong PH of 5.8 for my mix.

I stopped using the PH Down, and decided to keep a few plants in veg to see if they are affected - they are NOT. If it were only a matter of PH they would also be affected, yeah?

SOIL:

How long has this problem been going on? 3 crops
What STRAIN are you growing? past 2 were JH current is unknown
What was the establishing technique? (seed or clone?) clone
What is the age of your plants? 6-7 weeks
How Tall are the plants? 23-25"
What PHASE (seedling, vegetative or flower) are the plants in? 3rd week flower
What Technique are you using? (SOG, SCROG etc) lst
What size pots are you using? (Include how many subjects to pot) 1.5 gallon
What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?) Lambert LM3 (same as promix bx without microgoop) contents are peat, perlite, vermiculite, lime, starter charge.
What Nutrient's are you using? GH flora micro+bloom a la Lucas
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful* 1/3 lucas: 70ml micro + 140ml bloom per 100L
How often are you feeding? Every watering, which is 1L per plant every 2nd day
If flowering, when did you switch over to using Bloom nutrients? I use lucas in veg too at lower dose (5ml mic + 10ml Bloom at 1/3 dose every watering)
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect) 1st GH micro, mix, then GH bloom
What is the TDS/EC/PPM of your nutrients used? 400-420 including 70 starting tap water + 60 calmag = >300ppm nutes
What is the pH of the "RUN-OFF"? unknown
What method of pH test was administered? Using Strips? pH pen? pen
How often are you watering? every 2nd day 1L each
When was your last feeding and how often are you feeding? every watering
What size bulb are you using? 1000w hps
What is the distance to the canopy? 14-18"
What is your RH Factor? (Relative Humidity) 40-60%
What is the canopy temperature? 26-28 C
What is the Day/Night Temp? (Include fluctuation range) 17-28
What is the current Air Flow? (cfm etc.) MANY 8" vortex, not an issue
Tell us about your ventilation, intake exhaust and when its running and not running ? intakes are temp controlled, exhaust is always on and also cools/exhausts lights
Is the fan blowing directly at plants? not really
Is the grow substrate constantly wet or moist? no, i let them dry out almost completely before watering (no wilting)
Is your water HARD or SOFT? at only 70ppm i would say soft...
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? tap
Are you using water from a water softener? not that i'm aware (aren't they huge?)
Has plant been recently pruned, cloned or pinched? no.
Have any pest chemicals been used? If so what and when? neem only, once per week or 2.
Are plant's infected with pest's? very slight thrips presence, totally under control, zero other pests.

pics:
















Like I said plants from the SAME batch that remained in veg are UNAFFECTED. previously the tested runoff was 5.5 ph on my other grow, so we assumed that was the problem. using 1/3 lucas every watering brings my ph to 6.2-6.3 and I've been leaving it alone. i used to ph down to 5.8 with phosphoric acid, also on my previous grow, i don't use it now.

not really sure what else to try, i've been growing for years and this is a new problem (3 crops). first couple crops at this location were not affected. I'm stumped, it looks like PH spotting or maybe cal problems but i've been using calmag at about 1/2ml / L to bring my tap water from 70ppm to 130ppm, then i add my nutes which brings it to 400-420ppm PH 6.2-6.3

haaalp! lol

cheers

edit: Bold text answers

 

[stinkyattic]

Bring your soft tap water up to 250ppm using calmag before you do anything.
Give a timeframe for how long a plant, on average, resides in its pot after a transplant before you start seeing the spotting?
Don't bother acidifying your nute solution. And 5.8 is quite low- you are stripping the lime out of the soil very fast that way and the combination of not enough calmag, not enough lime left over, a peat based mix, and low pH watering solution is your issue.

Next watering, start with wter right out of the tap. You don't have to let it sit. Add CalMAg Plus to 250ppm. Then add your base nutes to your desired fert strength, then set the pH to 7 to counteract the low soil pH.

Check that your runoff falls in the vicinity of pH 6.6. If you can't bring it up over 6.4 just by watering with a higher pH fert solution, you may need to flush to raise it.

Generally, re-potting your plants once every 4 weeks and not using very acidic fert mixes will prevent problems caused by insufficient lime remaining in the soil.

Out of curiosity, if your water comes from a well or small town water source- what is the landscape, forest, and bedrock type around teh water source? I ask because high levels of organic acids in well water from areas with coniferous trees and igneous rock can really surprise you in how fast you go through the lime in your soil.


Edit: Re-reading your posts there are inconsistencies between the filled out form and the narrative description.

 

[Koskesh]

Bring your soft tap water up to 250ppm using calmag before you do anything. When I add that much the leaves turn very dark bluegreen, if that's ok I'll do it
Give a timeframe for how long a plant, on average, resides in its pot after a transplant before you start seeing the spotting? 6 weeks now in the pots, however the ones in veg are not affected and were planted at same time. it always starts 2 weeks into flower, apparently time spent in pot doesn't contribute
Don't bother acidifying your nute solution. And 5.8 is quite low- you are stripping the lime out of the soil very fast that way and the combination of not enough calmag, not enough lime left over, a peat based mix, and low pH watering solution is your issue. these haven't had a drop of acid. i add calmag and gh flora only which brings ph to 6.3. the 5.8 water and 5.5 runoff are from my PREVIOUS grow

Next watering, start with wter right out of the tap. You don't have to let it sit. Add CalMAg Plus to 250ppm. Then add your base nutes to your desired fert strength, then set the pH to 7 to counteract the low soil pH. that's how i do it, but much less calmag. i can add more if the blue leaves are not a problem. what is best to use for PH up? i think i have some potassium hydroxide but can buy whatever's best. so 6.3 is still too low i guess?

Check that your runoff falls in the vicinity of pH 6.6. If you can't bring it up over 6.4 just by watering with a higher pH fert solution, you may need to flush to raise it.

Generally, re-potting your plants once every 4 weeks and not using very acidic fert mixes will prevent problems caused by insufficient lime remaining in the soil. should i add lime, or can i top dress it?

Out of curiosity, if your water comes from a well or small town water source- what is the landscape, forest, and bedrock type around teh water source? I ask because high levels of organic acids in well water from areas with coniferous trees and igneous rock can really surprise you in how fast you go through the lime in your soil. actually it's city water, not sure why the ppm is only 70


Edit: Re-reading your posts there are inconsistencies between the filled out form and the narrative description. do you mean confusion with the ph or something else?

what i don't get is why the plants that didn't go into 12/12 are FINE. they're still in the veg room, i kept them there as a test to see if flowering has something to do with it - looks like it does i just don;t know what. if the lime is gone after 6 weeks shouldn't ALL the plants be affected not just the ones in 12/12.... it happens 2 weeks into 12/12 like clockwork.

there's another thread here that looks like the same issue : http://www.icmag.com/ic/showthread.php?t=104806

again thanks for your input, it's MUCH appreciated

is it possible that i'm under watering? the 1L each lasts 2 days til they're light/dry, that's with no runoff, ever. probably not ideal but i've always done that, and the problem is recent...still thought i'd bring it up

 

[stinkyattic]

It may be that your plants are uptaking calcium much more rapidly in flower? The stretch period is a very aggressive time of growth. This is just a hunch.
Okay if your leaves are turning dark blue-green from the N in calmag, then definitely don't use it at that level. *Sigh... light feeders lol...
Another way to go would be to scratch just a bit of lime into the soil surface and water it in.
Also, 6 weeks in one pot is IME as long as you ever want to go. Time to pot-up into fresh soil. This keeps you ahead of problems from what I'm trying to explain here. For example, when I start a plant from seed or clone, running a promix type grow, it first goes into either a rapidrooter or a 1.5 oz nursery 6-pax style seedling plug pot. Next, when it is fully rooted in that home, it goes to a 3" pot for ~2 weeks. Then it goes to a 5.5" pot for ~2-4 weeks, of which half is spent in flower. I transplant into the next pot after the first or second week of flower. Then it gets finished in a 2-3 gallon pot. Hopefully by this time it has only 6 weeks left to go to finish. If I were to run a long-flowered sativa, I'd add yet another transplant at about week 7, into a pot that is only SLIGHTLY larger, but honestly, if I were running a Sat, I'd be in coco compost (BioCanna) to avoid exactly this set of issues.
Hope that sorta helps?

 

[Koskesh]

actually i've only seen the blue-green from calmag in veg, last time around, which is when i first started using it - so i lightened up the dose and all was good. you may be right about the stretch, since this crap shows up immediately after the stretch. last time it did get worse throughout the crop, but that could be because i underfed early in flowering, and since my runoff was high ppm and very acidic i didn't feed as much through the rest of the grow - probably aggravating the situation...

i'm going to give them a larger dose of calmag next watering and see if it helps, i know affected tissue won;t recover but i'll watch and see if it gets worse like last time.

your stretch theory makes sense, since the plants i kept in veg are fine, maybe they didn't get that cal craving like the 12/12 girls. thanks again for your input.

i know i should repot 1 more time per cycle but frankly there are just too many, once they're in i don't really have the room or time to repot - but i definitely agree. if things don;t improve i'll figure a way to do it

cheers

 

[stinkyattic]

Okay, cool- good luck. Don't you sometimes wish you just had a shelf full of fertilizer ingredients and could just whup together a low-n version of calmag for your picky eaters? lol!

 

[mexilandrace]

Ia m kinda high so forgive my skimming

you have lime in your soil, or wait, how much did you use?

limeade sounds delicious right now...not for you plant, for me

 

[MynameStitch]

You better get your run off tested, it looks to me the problem is caused by pH swing and with using that high of dosage it can swing. collect the run off from the bottom of your pots and test the pH cause normally when spotting happens within the leaf veins there is something in it's rootzone that is causing the issue and black is necrotic causing tissue death, one issue can be caused by pH or too acidic or hot spots in the soil.

make sure your pen is calibrated before using testing.

 

[Koskesh]

You better get your run off tested, it looks to me the problem is caused by pH swing and with using that high of dosage it can swing.

...that high of a dosage of what? lol sorry if i'm confused, maybe i'm a little high.. i'll check the runoff in the morning.

stinkyattic, i wish all kinds of crap, might as well add that to the list but the calmag i use is Magi-Cal, it's got iron, cal and mag. i think its something like 2-0-0 whereas the one i first tried was jurassic, it was 12-0-0, just fyi

mexi, i didn't add any lime, my peat mix already has it in there, along with perlite, vermiculite, and starter charge.

thanks for the input people, hope it works out better this time. i did get a decent harvest last time, but the fan leaves were fried and i only got about 0.65gpw instead of the 0.8 i used to get...

cheers

 

[mexilandrace]

you should add lime

 

[b8man]

How are your temps, humidity and air-flow? Are they getting fresh air?

I used to get the same thing happening with my plants. They exhibited signs of calcium def and possibly boron def about 2 weeks into flowering, but it turned out that it was the environment which was too hot and humid which caused it.

Using exactly the same nutes but outdoors and they didn't exhibit a single deficiency.


Just a thought.

 

[Weedman Herb]

1 Liter of water per 1 and a half gallons of medium every other day? Feeding a soilless steady Lucas Formula GH Flora? You're barely getting that medium moist. You probably have dry pockets and the top layer forms a crust when the peat dries out. How much water will your pot with medium hold? If you don't know ... and you don't know how to measure it ... holler. Knowing this ... IMHO ... is the key to your problem ... I'm calling a lockout due to Salt Build Up ... Wanna know how to fix it? Start by running 4-5 times the amount of water your medium Holds through your pots ... let em drain and drip for a spell and feed them bitches a nute solution that matches the amount your medium Holds ... when the pots dry out completely (without the plants wilting) run 2-3 times the amount your medium holds through the pots and let them sit a spell ... then feed em. Continue like this until Final Flush. Keep this in mind ... As you Increase the PPM of your solution you must Increase the amount of water you run through to fully flush out the salts left over from the feedings. I told you to flush it fairly hard to begin with as I think you need to knock a good amount of Built Up Salts from the medium. Seriously ... keep soaking that peat mix until the runoff is clear before you think about feeding them again but don't just flush em and leave them foodless either ...

 

[Koskesh]

weedman, thanks for the reply. i give them that much water because any less and they'd be dry the next day - i tried watering to slight runoff (about 10%) and that was about 2L, but the pots took almost a week to dry out, and i was told that's no good, to have the medium wet for so many days...wrong?

with regards to flushing, i have like 150 per room, to flush them to the degree you suggest (while probably a very good idea) will be waaaay too time consuming - i'd have to sit like 4 at a time in the shower to drain lol

I do wonder what you meant by "Feeding a soilless steady Lucas Formula GH Flora?" something wrong with that? also do you have any theories as to why the same plants that were kept in veg are not affected?


b8man, my temps range from 17-28, 28 being canopy temp. humidity is acceptable at 40-60%. it once went to 65% but that's rare, since my airflow is also very good. i've got an 8" vortex every 3rd light, and my exhaust is always on. fresh air intake also cools my room, and is temp activated. i notice it comes on for a few minutes at least 3-4 times per hour ime.


thanks guys, great feedback

 

[Core]

looks like sal build up to me...feeding every other day is't needed....even if it is a weak batch of nutes.....and evey day is even worse to get a build up....soil or soiless does accumulate saltbuild ups the quickest....and to boot Promix Bx is already ferted so i suppose your s is 2......so there's need for a few days inbetween...

 

[Koskesh]

so u guys think i should feed full dose once a week instead of 1/3 dose every 2nd day? at full dose i'll need some serious PH+ should i use potassium hydroxide or what

cheers

 

[Cracky]

yes, too bad you just can't give 'em a nice tall glass of milk and a piece of pie.

 

[MynameStitch]

so u guys think i should feed full dose once a week instead of 1/3 dose every 2nd day? at full dose i'll need some serious PH+ should i use potassium hydroxide or what

cheers

I agree with what Core is saying too.
Yup, but you should go by the size of the plant rather then the directions with the nutes you are using.

With the pH not being known as well it adds to the equation, if when you feed that much every time like you do it can also cause pH issues as well, promix is supposed to be acidic a bit due to high peat moss.
WHat is full dosage directions on your nutes?

 

[Weedman Herb]

What I meant was ... you're creating a salty environment and your plants can't eat ... they can't even uptake the proper amount of water that they need and they are dehydrating and starving in salty pots. Yes 150 is a large amount to be fucking with like this ... You didn't do much research before you got going ... did you? You need to flush the excess salts from your medium. That's like a Bottom Line or a Period kinda thing. If you don't your plants are dead ... again. Then you need to establish a proper feeding cycle that allows for a gradual increase in PPM while still dealing with the salt build up. I call this the Flush and Feed method. Just feeding has gotten you where you are. You aren't in a happy place and neither are your plants.

 

[Weedman Herb]

Take 10 plants ... or 5 ... or even just 1 ... the worst of them ... and at least try what I have suggested. Feed them/it the same ratio as your last feeding but do it After you've run the excess salts out. When the pot dries out (without the plant wilting) repeat flushing with just 2-3 times the amount of water your medium/pots hold and feed with a slightly stronger nute dose (never increase ppm by more than 200 points IMHO). I am successfully doing what you want to with ProMix BX and perlite, fed with GH FloraNova, Floralicious+, CalMag+, Sensizym (for the root zone), and a few doses of KoolBloom just before the Final Flush. Simple but effective. I don't put food on food in the medium and I don't feed a dry medium either. I don't own a pH meter or an EC pen or a Truncheon. Here's a Mass Super Sk X Sourbubble that is waiting to be fed after a flushing ... she's well past your 2 weeks of flowering and looks ok to me. What do you think? Note the cooler full of water on the right side in back. It's about to be full of salts and Gone.

 

[Koskesh]

I agree with what Core is saying too.
Yup, but you should go by the size of the plant rather then the directions with the nutes you are using.

With the pH not being known as well it adds to the equation, if when you feed that much every time like you do it can also cause pH issues as well, promix is supposed to be acidic a bit due to high peat moss.
WHat is full dosage directions on your nutes?

the ph is known, it's been 6.2-6.3 with the nutes in. i'm using gh flora mic and bloom as i said, lucas formula is 8ml mic 16ml bloom, i'm giving 1/3 of that every 2nd day. thought i was clear on that, sorry for any confusion.

if i do put the full lucas dose of 8 and 16ml, the ph will be like 5.9 - what to use for ph up becomes the question...

cheers