Threatco - Little black circles - Flowering day 22

[threatco]

Hello folks.

Been keeping an eye on my leaves since some visual imperfections showed up last week on a couple of leaves. I would appreciate anyone sharing their experience and helping diagnose what is on my leaves, and prescribe a remedy.

Background:

100cm by 100cm, 200cm tall grow tent. Ebb and flow in Hydroton. 3x 1500w KingPlus LEDs, 24 inches above the canopy, the middle LED set to half power. 5.5-6.5 range PH. 30ppm tap water, nutrient range from 300-750 between full refills. Remo Nutrients. 6-inch 340 CFM inline fan creating positive pressure in the tent from the bottom. Flaps near top open to let air-flow up through leaves. No carbon filter. Temp range 65-81. rH range 31-49%. Growing NL#5 x Haze and Ice Cool. Never foliar spray or get leaves wet.

Last week I added the third light, at first at 18 inches. So I was watching closely for heat stress/ bleaching / burnt tips. I ended up not finding what I expected.


Situation:

For the past week, there have been a very small number of leaves that have caught my eye as having imperfections. I was assuming it was related to the extra light so I reduced ppm, raised lights while reducing intensity 16%, and kept an eye on it.

The above plan did stop the minor tip burn I started seeing in some places. But these other spots kept drawing my eye. So today I cut off 4 leaves for a look with a digital cam on zoom, and some 60x/120x microscope pics.

I labeled the leaves A, B, C, and D.

A and B are the ones I am concerned about. They show little black rings on the underside and a faint orange rusty color on the top side.

I would say there are maybe only 2-5 leaves in the whole tent that have similar signs but not as bad.

D is my control. I cut it from near the same part of the canopy. This is what 99% of my leaves look like. To my eyes, just about perfect. This is posted for comparison purposes.






C is another story. You may have seen in the LED lights forum my Kingplus rebuild. In that, I drilled some holes in a license plate to rig up a new light.
Not being a handy kind of guy, I did not anticipate how many tiny little bits of metal drill debris can remain even after wiping it down. So after mounting the light, I found a couple of leaves with a handful of tiny tiny dust size little metal bits on them. I think these cause some kind of light burn where they were heating up by the direct LED light. I have added the pics of C leaf for curiosity's sake.

So what do you think?

C pics in reply.

 

[threatco]

Pic for C from above. 20 pic per post limit.

 

[threatco]

I assumed with rH in that range I was safe from fungus problems.

But maybe I should trim the lower/middle canopy and get more fans in there. The leaf density gets very high just 6 inches from the grow media to the top of the plants. I wanted more larf for extraction purposes so let these master-cropped girls keep their 70s pornstar-style bush. I have 1 oscillating fan in the top corner + the big inline fan. Thought that would be enough.

I also maybe should put some kind of filter/nylon over the inlet fan. In hindsight, I assume it is blowing in the a bit of dust/spores off the floor, which is not far from a frequently open window. Not sure best practice for that.

I am guessing some sort of baking soda spay to stall it, and some kind of Copper Fungicide to halt it might be in order. But would like some confirmation before I do something that causes more harm than good.

 

[threatco]

@Beachwalker @Aqua Man @Dirtbag @One drop

 

[Aqua Man]

@Beachwalker @Aqua Man @Dirtbag @One drop

Got a whole plant pic? Near the bottom leaves?

 

[threatco]

Got a whole plant pic? Near the bottom leaves?

Very dense bush and short. Mutiple growing intertwined in flood tray. Hard to get individual plants but here is more angles.

 

[Dirtbag]

If it's up top I think it's the start of Calcium deficiency. Your starting water is low ppm, itll require some supplemental Ca.

 

[Aqua Man]

Idk looks pretty good to me. Not sure I would be to concerned with a couple leaves

 

[Dirtbag]

What's the % Calcium in those Remo nutes.

Those small brown spots are how Ca deficiency starts.

 

[Aqua Man]

If it's up top I think it's the start of Calcium deficiency. Your starting water is low ppm, itll require some supplemental Ca.

Yeah kinda what I was thinking at first cal up top or mag down low. Was also thinking it's pretty dense in there and damage may be from laying on other leaves.

Idk if it's just me but I don't see much issue. Of course my eyes are shit and this is not the biggest phone

 

[threatco]

Best news ever.

I have been adding less then 1/20 the suggested MagnifiCal. I wanted to wait to see signs of "needing it" before I just throw $$$ away drowning them in it.

Ill up the dose and see how it goes.

Thanks guys!

 

[Dirtbag]

Theres your problem. Happy to help.

 

[threatco]

I added full recommended dose of Magnifical to my new fresh reservoir of nutrients. Noticing symptoms on some of the most photosynthetically active leaves. But still visably impacting 1% of canopy.

Picked 3 of the worst ones and one normal one for photos.

Think I should stay the course?

 

[Dirtbag]

Yeah man, you're bringing the ship around and it wont happen overnight. Just keep an eye on new growth.

 

[threatco]

I wanted to mention as well. PH is staying steady near 6.5 naturally. PPM is actually going down every day as the reservoir water level goes down. from 750 ppm, to 600, to 450 over three days. My PPM normally goes up over time.

 

[Aqua Man]

I wanted to mention as well. PH is staying steady near 6.5 naturally. PPM is actually going down every day as the reservoir water level goes down. from 750 ppm, to 600, to 450 over three days. My PPM normally goes up over time.

When the ppm is going down daily try bumping the feed up by 50ppm each day until it levels off

 

[threatco]

When the ppm is going down daily try bumping the feed up by 50ppm each day until it levels off

Done and done.

Topped it up with strong enough nute solution to come back up to 750 ppm. again full strength magnifical/bloom/micro/astroflower

 

[threatco]

Update.

The issue continues to get worse. More existing canopy leaves continue to develope new visable signs of deficiencies.

I estimate about 20% of the canopy now has signs beyond just tip burn.

Since my post i gave it 100% reccomend Magnifical along with normal dose of micro bloom and Astroflower. That's 750 ppm in my 30 ppm tap water. 6.0 to 6.5 ph range.

In 48hr ppm went down to around 450.

Topped it up with same mix of nutrient solution as before. Back up 700 ppm.

In 48 hours it went up to 900 ppm

Topped up with 30ppm tapwater. Diluted down to 750

48 hours later almost half the water is gone, ppm steady at 750.

I have not pruned or stressed them.

Admittedly temps have been getting as high as 86f briefly. More often 79f during lights on.

Might I simply have too much light in there?

 

[Aqua Man]

What are your sources of P? Adding any pk?

 

[threatco]

I was using about 2/3 the recommended dosage of Remo's Bloom, Micro, and Astroflower until a week ago when I made this post. Since then, 100% recommended.

I was using 1/20th recommend Magnifical until a week ago when I made this post. Since then, 100% recommended.