Same Problem AGAIN - Necrotic Spotting (pics)

[Koskesh]

You didn't do much research before you got going ... did you?

lol... i guess i've been lucky for the past 6 years, but never had a problem. this is new the past few months. i used to give even less water, like 500ml per, at like 800ppm every watering haha they were kinda crispy sometimes near the end but never had these types of issues so early in flowering..

is it ok for them to take 3-4 days or more to dry out? i thought that was bad

 

[MynameStitch]

kosh,. I don't see where you stated your pH, you listed it as unknown, not to mention your posts in here I read and I did not see where it says your pH was that.......

No, you want them to slightly dry out, but never completely dry, cannabis likes a good watering and then a little time in between to allow to dry a bit....... soiless I think you may have to water more than soil, but still allowing a little time to dry is ok as long as the mediumj does not end up dry where if you touch it no moisture is on your hands.

 

[Koskesh]

you're right stitch, i looked over the form, and it doesn't have a field for ph goin into the medium, only for runoff. i spelled it out in the paragraph following the form though. the only unknown ph is of my runoff, which i haven't tested. i will.

by what you say, as well as some of the others, looks like i'm under watering. i do let them get very dry before watering, but with no wilting. thought that was correct, that the roots could not breathe otherwise. thanks for setting me straight.

if i double it to 2L per plant it'll take them 3-4 days to be thirsty. wouls it be best to feed full dose once a week, and one plain watering? or half dose every time? plain water means PH down, i don't want to use acid do i

 

[Koskesh]

i have phosphoric acid for ph- and potassium hydroxide for ph+ but i haven't used them. the nutes bring the ph to 6.2-6.3. but if i go full dose nutes ill need ph+ of some kind

 

[MynameStitch]

First you need to check pH before you add ANYTHING to the mixture.

As for the dosage, what does the dosage say on thye back?

Again I said prevoius post, do not go by the directions on the back, go by the size of the plant, I know it sounds confusing, but normally you should use 1/2 dosage by what the directions say.

So if your directions say use 1 tsp per gallon, you use 1/2 teaspoon per gallon.
How big are your plants now? What nutes you going to use on them the same ones you listed in the first post?

 

[sirgrassalot]

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

You'll need one big pie to go around here. Who's up for the first slice?

I grow with PM BX or HP & mine doesn't come with ferts, I add them every watering which is about every third forth day. I'll add 10 - 25% ~ 10 - 25% than a full dose & repeat without overfeeding. I don't mess with the pHing of it, we have no need to do that with our city water using this method. (Maybe some others have also learned to grow this way, anyone?). I have seen the spotting your leafs are showing in a recycled PM plant once in veg. I cured it by transplanting into a larger pot adding fresh PM. She never showed it again.

 

[Koskesh]

stitch, the ph of my tap water before anything goes in is 6.8 and the ppm is 70.

the gh flora directions range from 1/4 tsp for seedlings to 2 tsp /g mic and 3 tsp/g bloom. i've been giving 1/3 of that dose every watering, which is every 2nd day 1L of solution.

my plants are about 25" tall.

Sirgrass, thanks for the input, what you say furthers the theory that i'm underwatering and letting them get too dry in between... i think adding 10-25% on your "off" waterings is what saves you from having to adjust ph, which is what i was trying to accomplish by watering with 1/3 dose every watering...

i'm still confused as to why the plants still vegging (which are the same age and size) are not affected. so far the only theory that makes sense is stinkyattic's, that they are hungry from the stretch and being underfed..

 

[Koskesh]

so judging by what all of you have said, it seems i have to:

-add more calmag during the stretch
-water with 2L instead of 1L (every 3-4 days instead of every 2)
-don't let them get too dry between waterings (light, but not dry)
-increase nute dosage gradually according to plant size, not life stage

if these points are correct, i have a couple of questions that seem to have slipped by unanswered:
1. what should i use to correct my PH (phosphoric acid, potassium hydroxide, etc)?
2. what is the ideal ph range? i ask this because i've gotten different opinions, some say use soil range of 6.2-6.8 and some say soilless range of like 5.5-6.3.

on the grow right before this one, when i tested my runoff it was 5.5 and people here said that's way too low for my mix so i started flushing, but i've seen stitch recommend that range for soilless.....dunno which is right

 

[Koskesh]

+rep to all u guys, but "i must blah blah blah before i can give it to stinkyattic and sirgrass again" thank you all for your input, hopefully i can pay it forward when i'm all grownzed up


edit: i tested my runoff, it came out 6.2 ph. that's the same as i've been putting in, so that's good, right? previous grow i would put in plain water 6.8 and runoff would come out 5.3-5.5 lol but that when i was ph'ing to 5.8 like a tard

 

[HeadyPete]

1. what should i use to correct my PH (phosphoric acid, potassium hydroxide, etc)?

yes and yes. (depending which way you need to go)

Phosphoric acid is ph down and potassium hydroxide is ph up.

 

[Koskesh]

thanks

 

[Skipload]

If you just switch to hydo you soil growers can sleep better at night. JK, enjoy that soil.

 

[Hydro-Soil]

I recommend installing a quality RO machine.
Mix and feed full str Lucas Formula.
Water the next two waterings with straight RO water.

You'll have a whole lot fewer pH issues and you're plants will probably be happier.

Personally, and I REALLY don't recommend this, I'm running the Lucas Formula in DWC with RO water. Haven't checked pH, EC or TDS for 21 days now and they look beautiful. (Don't have any way to check in the first place)

It's the only formula I recommend for anyone to get great results whether they're in soil, soilless or hydro.

I know it's not always feasible to install an RO machine but it will really cut down on your maintenance time. You'll be surprised. (and your plants will LOVE you)

 

[Koskesh]

i thought about an RO machine but my starting water is ph 6.8 and 70 ppm that's pretty close to RO isn't it? i agree about the lucas formula, easy and works great

i think it's been boiled down to watering/feeding issues rather than a simple ph issue (thanks to exhaustive pm's with Weedman Herb lol cheers m8) and of course all who contributed to this thread

happy to report the ladies are looking good, the problem seems to have slowed drastically, compared to the progression on the previous run. all new growth looks mint, and the affected tissue doesn't look much worse at all. thanks everybody

 

[rckymtnthuglife]

I'll throw my two cents at ya. Check out Organics for beginners sticky in the organic soil section. Great soil recipes and feeding regimens in there. Here are some specific suggestions I have for you in order of importance.

1. Add two tbs of dolomite lime per gal to your mix. This takes care of Ca, Mg and pH issues.

2.Put those plants into bigger pots.

3. Water your plants when the pots "feel" light not heavy...number of days between waterings means absolutely nothing. Someone I'm sure can elaborate on this. Using a promix based mix means you'll have to water each plant a cup or two....wait half an hour...then thoroughly water until you get some runoff....especially important with the chemical salts your pouring on your plants. Again the amount of water means nothing water till you get runoff. Hell this might be more important than bigger pots.

and JMHO stay away from pH up and down unless you enjoy lockouts...someone will burn me for that OH well.

Peace
Rocky

I guess I should explain the need to water twice. Basically, it's the only way to evenly saturate the soil...so there aren't any dry pockets. Also the first watering is just plain water or has humic acid added and the second watering....the real soaking is the nute water...this helps to not shock the root system.

 

[Koskesh]

thanks for the input rcky, it's along the same lines as the convo i been having with Weedman Herb - except for the added lime: i go through at least 4 bricks of medium every month, it would be HUGE pain to try to evenly mix lime into it. Unless I can top dress it or something...

but yeah, the pre-watering + saturate is already making a world of difference and it's only been a few days. cheers

 

[HeadyPete]

The problem with dolomite lime is it is too slow acting to be useful for you unless you make your batches weeks or even months in advance and let the lime break down.

Top dressing will not work. Lime only affects the immediate area around the lime particle, it won't precipitate through the medium.

Some issues with RO is the cost of the unit, plus the cost of all the waste water down the drain it produces while making your RO water.

They recover only 5 to 15 percent of the water entering the system. The remainder is discharged as waste water. Because waste water carries with it the rejected contaminants, methods to re-cover this water are not practical for household systems. Waste water is typically connected to the house drains and will add to the load on the household septic system. An RO unit deliver-ing 5 gallons of treated water per day may discharge 40 to 90 gallons of waste water per day to the septic system.

 

[minds_I]

1. what should i use to correct my PH (phosphoric acid, potassium hydroxide, etc)?

yes and yes.

Phosphoric acid is ph down and potassium hydroxide is ph up.

Hello all,

Firstly, you DO know about mixing acids and bases RIGHT?

Well, if you don't you will.

You should first dilute the acid in the fluid and slowly and a little at a time add the potassium base.

Just some basic chemistry.


minds_I

PS acid + base = salt + h2o

H3PO4 + KOH ----> K3PO4 + H2O..... unbalanced H3PO4 + 3KOH ---> K3PO4 + 3H20 ...... BALANCED ...cute from wiki answers

 

[Koskesh]

thanks for the lesson minds I but i'm not going to mix the 2 into the same solution lol

frankly i doubt i'll use either any more. my water is pretty good at 6.8 ph and 70 ppm and the nutes don't bring it too low either, so screw PH+/- and RO.

plus i'll be shortening my veg period and/or adding a beer cup stage between the tray and the final pots, either way less time in the pots = less issues.

and......things are looking 100 times better at 4 weeks flower over the previous run! last time at this point all the large middle fans were toast, and the upper ones were starting to spot. by 7 weeks all fans with a visible stem were crispy, and the girls were thankfully ready before the buds cooked (scary!). THIS time, 4 wks in only about 15% of leaves are affected, max. and it doesn't seem to be getting worse

sooo, feel free to keep posting in this thread, all info/help/opinions are welcome and appreciated, but i think i've got a handle on things now

one thing i'm confused about is why the heck this never happened before - only the past few crops and i've been growing 6 years+. maybe insanely lucky or some forrest gump secret that i've since lost hahaha

cheers

 

[HeadyPete]

No one suggested mixing acid and base together.