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First coco grow - Need help with my Northern Lights with rusty brown spot. CalMag?

ftleroa

New member
Hello guys, I'm on my first coco coir grow and I'm having issues with 2 out of 5 plants so far.

I'm using coco coir with 25% perlite and a bottom layer of rocks in 3 gallon smart pots.

I feed them Canna Coco A+B 8ml/gal and 5ml/gal of CalMag.
PH 5.8 - 6.0
Temp around 77F and 25% RH (low!)

On my Northern Lights I see a lot of brown rusty spot, even on the recent growth so I'm very worried. It's slowly getting all over the plant so I need to adjust something but I don't know what exactly!

nqfEBBh.jpg


Recent growth, little dark spots: http://i.imgur.com/xSkiwqC.jpg


Now, a different plant, this one is less severe but my White Widow x Big Bud has small yellow patches on the leaves.

http://i.imgur.com/OMNRA6M.jpg
http://i.imgur.com/BIR6v9v.jpg


Very purple stem, is this a Phosphorous deficiency?
http://i.imgur.com/qAHaDcR.jpg

Thanks a lot in advance!
 

maimunji

Active member
Looks like P def. Try drop cal mag. Flush with basic nutes 10-12 per gallon. Test run off ppm. if spreads give them 2ml/gal. canna pk if you have.
 

Loc Dog

Hobbies include "drinkin', smokin' weed, and all k
Veteran
I would first check the PPM/EC of your runoff. I had plants that looked similar, but not as bad, that had thrips and mites. Use a microscope on the backs of some of the bad leaves. They are extremely small.

Also, if first coco grow, either add a layer of diatamecious earth to the top of coco, or use mosquito dunks in all water. I let the water sit for 2 days, then move the dunks to fresh buckets of water. It was the only way I got rid of fungus gnats. I used airpots, so could not use DE, because of all the holes in sides and bottom.
 

maimunji

Active member
I also have simular problem in peat most compost but combined with yellow tips at new growth but without purple stem and petioles Only thing that help me is cal mag full dose every water but soon or later this feedings give me massive lockout and throw everything out of balance.
 

Big-Narstie

Member
You using tap water? What the EC of the water before adding nutes? Just bare in mind if your in a hard water area your water will b full of cal so adding calmag is detrimental...
 

ftleroa

New member
Looks like P def. Try drop cal mag. Flush with basic nutes 10-12 per gallon. Test run off ppm. if spreads give them 2ml/gal. canna pk if you have.

I was thinking either P deficiency or CalMag related.

My TDS meter is cheap and probably not accurate but runoff is at 950PPM.... 5.4 PH

I would first check the PPM/EC of your runoff. I had plants that looked similar, but not as bad, that had thrips and mites. Use a microscope on the backs of some of the bad leaves. They are extremely small.

Also, if first coco grow, either add a layer of diatamecious earth to the top of coco, or use mosquito dunks in all water. I let the water sit for 2 days, then move the dunks to fresh buckets of water. It was the only way I got rid of fungus gnats. I used airpots, so could not use DE, because of all the holes in sides and bottom.

I'll check under microscope tonight but I'm pretty sure it's related to the feeding. Only 1 plant suffers from that and it's that one, and since the 1st set of leaves. Something is missing or too much.

Cheap TDS-3 meter says 900 PPM runoff and 5.4-5.5PH so that could tell something.

So you think I should add a layer of perlite or hydroton on top?
 

ftleroa

New member
You using tap water? What the EC of the water before adding nutes? Just bare in mind if your in a hard water area your water will b full of cal so adding calmag is detrimental...

Cheap TDS meter says 70PPM for my water, pretty low I think.

Everyone says that Coco nutes and tap water has enough but some also says some strains really need it or become all brown rusty. No idea if this is even it.

My runoff is high though, I'm worried about that now.
 

siegoldie

Member
drop the cal mag if using tap water and canna coco a+b you don't need cal mag at all , your ph is off too up that to 6.0 , i have hard water my tap water ph is 8.2 i use 5ml of a+b per ltr (my strain is a heavy feeder )i feed every day with no run off but do give them plain ph 6.0 water once a week
 

Loc Dog

Hobbies include "drinkin', smokin' weed, and all k
Veteran
Cheap TDS meter says 70PPM for my water, pretty low I think.

Everyone says that Coco nutes and tap water has enough but some also says some strains really need it or become all brown rusty. No idea if this is even it.

My runoff is high though, I'm worried about that now.

70 PPM is low. It is not chlorinated is it? That runoff is not bad. I have fed 600 PPM and had 2500 PPM runoff. You could try half strength feed once a week, with some Florakleen. You can get PH and PPM test solution on e-bay, or elsewhere, very cheap, and it is worth peace of mind. I had PH meter with batteries dying, and gave bogus results. I used 7.0 test solution and calibrated the unit to that, and still had problem. You want to test at 7 and 4 PH, to be sure. This chart could be helpful.




This is the stuff for a barrier on top of coco. I have not used, but many have -

http://www.ebay.com/itm/100-Food-Grade-Natural-Diatomaceous-Earth-2-Lbs-POUNDS-FASTEST-DELIVERY/131532820103?_trksid=p2047675.c100010.m2109&_trkparms=aid%3D555012%26algo%3DPW.MBE%26ao%3D2%26asc%3D39825%26meid%3De42aa5695ab34bbfac1fbd6f69b68872%26pid%3D100010%26rk%3D6%26rkt%3D6%26sd%3D282078231147

I used mosquito dunks, in all water the plants are fed, and yellow sticky traps hung in area, to get any that survive. They have a bacteria known as BTI, which eat the bugs from the inside. They are only known to effect mosquitos and fungus gnats. I have never had coco that did not contain fungus gnats.

Also, research your strain, especially if clone only. GG4 I never needed cal/mag, but a couple of OG's I tried needed it. The OG's were also much more prone to mold.
 

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