K or Ca Def? pics

[Koskesh]

Hi all, a while back I had some issues which you guys helped me solve - the following run went great, all healthy looking and 11 lbs from 8 1k hps. The run after that however, I noticed toward the end they were showing signs of def, but no biggie with 2 weeks til the chop...

This time around, the same signs are showing at 4 weeks 12/12. Pretty sure it's K or Ca, since I did bother to ready the stickies as well as some adv searches.

I'm leaning toward K rather than Ca, but since my starting tap water is only 70 ppm I'm having doubts. I know Lucas says I shouldn't have to add anything to 0-8-16 but signs are signs...

So here are the pics, you can see the tips and margins are brown, as well as some twisting:


Sick Plant Sticky for those interested:

/Soiless/

How long has this problem been going on? 1 week
Are you growing in a PVC grow tent? (example: Hydrohut or any other non brand tents) no
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...) hand watered
What STRAIN are you growing? old jack herer clone
What was the establishing technique? (Were the seed or clone?) clone
What is the age of your plants? rooted 8 weeks ago
How long have they been in there mixture they are in now?(coco,soiless etc..) 8 weeks
How tall are the plants? +/- 4ft
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in? 5 weeks flower
What Technique are you using? topped once and/or au naturel
What substrate/medium are you using?(Hydroton, RockWool etc.) triple mix
What is the Water temperature?
What color are your roots? White? Brown? Are your roots slimy? white, very few slightly yellowing
What Nutrient's are you using?(If growing soiless) GH flora Micro and Bloom
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful* 0-8-16 per gallon
How often are you feeding? (If using soiless) once daily
How often are you giving nutrients? (If using soiless)
If flowering, when did you switch over to using Bloom nutrients? great question! 2 weeks into 12/12
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect) as per label, first micro, then bloom
What is the TDS/EC/PPM you are using? Oakton
What is the pH of the "Tank"? 5.9-6.1
Are you sure your calibration is correct on your equiptment? yes, compared readings with hydro store's pens
When was your last watering? today
What is your water temps? +/- 24c
When was your last feeding change? (ie. grow-bloom-micro-additional)
How often do you clean your system: example: Flush out water replace with clean water and nutrients? N/A
What size bulb are you using? 8x 1k hps
What is the distance to the canopy? +/- 20"
What is your RH Factor(Relative Humidity)? 30-50 flower, 40-60 veg
What is the canopy temperature? 77-80
What is the Day/Night Temp? (Include flucutaion range) 60-80 (80 being hottest canopy temp
What is the current Air Flow? (cfm etc.) 650 cfm 8" intake, 3x 650fcm thru lights and out
Tell us about your ventilation, intake exhaust and when its running and not running ? 3 8" exhaust thru carbon filter and lights, always on. 1 intake on a thermostat
Is the fan blowing directly at plants? not for the most part
Is your water HARD or SOFT? soft? 70-80 ppm and ph 6.8
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? tap
Are you using water from a water softener? no
Has plant been recently pruned, cloned off of or pinched no
Have any pest chemicals been used? If so, What and When? never. a light neem foliar 1st week of 12/12
Are plant's infected with pest's a family of thrips that comes back about every 3 months or so lol - NONE at the moment, but they'll be back...totally under control, not an issue. I know they can sometimes cause some leaf curl as well as the usual sucking.

 

[resinryder]

The Triple mix you're using as the medium, what is it? Never heard of it. Soil less mix or soil based?

 

[Koskesh]

Sorry for any confusion, by triple mix I mean Peat/Perlite/Vermiculite. The brand is Lambert LM3, also contains D.Lime and a wimpy starter charge. It's like Promix BX without the myc.

 

[resinryder]

How is the ph of your run off or have you checked it? Peat can be be acidic and cause ph problems.
I'm leaning to nute lock out due to low ph levels causing your problems.

 

[Koskesh]

I haven't checked it. If that were the case, wouldn't I see more defs? The mix does have lime in it already, maybe I should try watering with a higher PH.. will check runoff tomorrow - I hate doing it cuz the medium stays wet for days and that plant always gets VERY angry for the rest of the grow lol but I can select a Guinea Pig I s'pose

 

[HeadyPete]

I say ph too high....lime in the mix plus water at 6.1....

check runoff to confirm.

 

[Koskesh]

yea, will do pete. the water's usually 5.9. in early flower I use some b1 which raises it a little to 6.1, and I leave it which maybe I shouldn't... i'll get back with the runoff details when lights come on

 

[resinryder]

Wait until your next watering to check it. No need to over water 1 at this point.
Here's my line of thinking.
D Lime is used to help keep a ph in a set range. Now, you've got a neutral ph medium mix. You are adding your nutes at an acidic ph range to a medium that is designed to maintain a higher ph due to the addition of the D Lime, peat moss, that can be acidic in itself thus the need for Lime addition.
The lucas formula you are using is a tried and proven formulation that works in the correct ph range for the medium it's used in, (hydro, soil, soil less)
If you are getting curled/twisted leaf edges, it would be a clue to me, and again this is strictly my opinion, I'd look at the ph to see if that was causing what appears to be the deficiency. I noticed you didn't say the tops of the plants where the new growth is was having any yellowing issues, which is a major indication of needing more Calcium.
Just my 2 cent.
I could be totally wrong and Heady Pete has alot of knowledge on the subject. I'm interested to see what your run off ph is.

 

[HeadyPete]

sounds good.

 

[HeadyPete]

Why raise it when a runoff test will confirm?

You almost got it RR, the more lime, the more it will raise...there is no set point.

 

[Koskesh]

yea that makes sense. i won't raise my ph til i see what's coming out, but yea i was thinking it needed raising. pots are dry tomorrow anyway, so will test runoff and see if ph is the problem. cheers

 

[HeadyPete]

I am curious to see what the runoff is, but yes as ResinRyder said, wait till your next scheduled watering.

The more food in the soil, the more microbes and their excrement (nutes for the plants) is acidic and will lower soil ph

and

ph will raise as food is depleted in the soil.



Good luck and I hope this gets fixed nice and quick.

 

[Koskesh]

thanks, will report after test.

Gratuitous porn I chopped yesterday:

this nug is 4" wide lol