Some help please, yellowing issues.

Hey all. I posted this in the coco coir section but maybe more appropriate here.

I have a new room setup and some issues with yellowing. Starting mid leaves it appears. They are about a week into flower.

Its a sealed room running co2 at 1100-1200 ppm (using controller). I have low to mid 80's canopy temp. Keeping it at temps of about 70-72 with lights out. Currently I am keeping it at 55 percent humidity with lights on and 45-50 with lights out. I am able to adjust humidity anywhere from about 45 up to 80+ if wanted/needed. As of now I am venting 5 times a day for 20 minutes each. when lights come on and then every 4 hours and once in middle of lights out.

I am growing in canna coco using canna coco nutrient line.

I started at 1.3 EC and have since upped it to 1.6 EC (RO water)

PH is currently at 6.1. I started it at 5.9.

Started with

350 A and B
200 Cannazym
75 rhizotonic
125 cal mag plus
100 silicia

I have since added an additional 100 ml of A and B and additional 75ml of cal mag

I don't start using boost until flowers start appearing, around day 14-18.

Idea what may be going on? This is the 2nd grow in this new room and I had very bad yellowing issues with first run as well. I was not running cal mag or silica in that run. That is why I have started using it this run to see if it happens again.

Thanks for any info.

Hey,
what about your drain ? What is the ec level in the drain ? is looks like that the coco is a bit oversalted. (Sorry english is not my mother language)
I would check the ec level of your coco.

Shizzlenator said:

Hey,
what about your drain ? What is the ec level in the drain ? is looks like that the coco is a bit oversalted. (Sorry english is not my mother language)
I would check the ec level of your coco.

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I am recirculating the nutrients from a 40 gal res, it is not being top fed, its just flooding the tray and it is being being soaked into the coco from the bottom. Also they are only 6 days into flower I think it is.

I spent a year with leaves looking similar to those pictured.

My case turned out to be a combination of bad lights and bugs in the roots.

Too much red causes early yellowing. This has been documented using HPS (orange/red at 630 nm) and bloom booster LED (red at 660 nm). This is an overall yellowing and does not seem to cause further damage.

Yellowing at random, usually starting on larger leaves, generally was accompanied by larvae in the root system interfering with nutrient uptake. Fungus Gnats do not directly eat the plant, they merely get in the way, while other bugs will directly damage the roots even in much lesser concentration.

Looks like magnesium deficiency to me.

And that would match up since you were not using cal/mag and have just started it....

Phaeton said:

I spent a year with leaves looking similar to those pictured.

My case turned out to be a combination of bad lights and bugs in the roots.

Too much red causes early yellowing. This has been documented using HPS (orange/red at 630 nm) and bloom booster LED (red at 660 nm). This is an overall yellowing and does not seem to cause further damage.

Yellowing at random, usually starting on larger leaves, generally was accompanied by larvae in the root system interfering with nutrient uptake. Fungus Gnats do not directly eat the plant, they merely get in the way, while other bugs will directly damage the roots even in much lesser concentration.

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I did have a fungus gnat a few months ago, got rid of them for the most part (have a few flying around here and there still) with mosquito dunks and sticky traps.

I will take another look at the roots, but just had repotted them a week ago when I put into flower and noticed no pests but I will definitely take a closer look.

I have been using these lights for a number of years, the bulbs are about 4 months old (hortilux). I also have a few new Gavita 1000's in the room, these particular plants are under 1000 hps though.

CosmicCharlie said:

Looks like magnesium deficiency to me.

And that would match up since you were not using cal/mag and have just started it....

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I wasn't using cal mag in the last set that went into flower, this set I am using cal mag, in veg as well for the past 3 weeks or so.

Ok I saw your other thread that is the same.

I'd agree with Poweredbylove that your EC is too high and might be locking out Magnesium. It def looks like mag deficiency to me.

How did your last run without cal/mag look? Same symptoms?

CosmicCharlie said:

Ok I saw your other thread that is the same.

I'd agree with Poweredbylove that your EC is too high and might be locking out Magnesium. It def looks like mag deficiency to me.

How did your last run without cal/mag look? Same symptoms?

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Yeah last run was very bad yellowing.. lost half the leaves in a few plants. That was with ec at 1.3 for the most part and no cal mag.

Am I correct in that you are using Cal Mag at the rate of 125ml per 40gal or 3.25ml per gallon? That sounds about right to me brother. I've seen some coco guys push it up to 5ml though.

Have you considered using something the House & Gardens Drip Clean to minimize the possibility of salt issues? That product is also very popular among coco folk.

TheMan13 said:

Am I correct in that you are using Cal Mag at the rate of 125ml per 40gal or 3.25ml per gallon? That sounds about right to me brother. I've seen some coco guys push it up to 5ml though.

Have you considered using something the House & Gardens Drip Clean to minimize the possibility of salt issues? That product is also very popular among coco folk.

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I started using cal mag after the first weeks of flower, which the damage was done already, I was using approx 3.5-4ml per gallon, still using that now as well (using both canna still and jacks 3 2 1, doing some experimenting).

Part of the issue was underfeeding I think of that strain, which was exodus cheese I had grown from seed.. so not sure what the genetics really were, some exo cheese I ordered from herbies head shop like a year or more ago.

Environment wise I have been keeping it low 80's canopy and 40-50% humidity with ~900 ppm co2. I want to go back to the VPD chart and do mid 80's temps and ~75% humidity but my room is perpetual and a little concerned about late flower. I think it would be fine as long as I watch out for moisture/dew and get my lights off temps/humidity set so its not a problem with that.

I have been flushing about every 2 weeks, maybe 2-3 gallons in each pot of straight ro.. then manually top feed nutrient solution right after. (bottom feed in flood and drain).

You could easily be correct on the Exodus Cheese genetics brother. She is one of my all time favorite strains and in all my years of working with her and her crosses I have never been able to quite dial her into my liking. Still some of my favorite meds in the cabinet regardless of how ugly they maybe ;-)~

See that on my lower leaves from time to time and associate it with bugs. Spinosad seems to help but never quite gets rid of them.