weird stuff on leaves.

My plant is 11 days post 12/12 flip and while I had a few like this in veg, never this many had the rust colored stuff. The leaves look perfectly healthy and show no signs of anything on the back side. Maybe its strain related? My tent does dip down to 67 at night so maybe it that? No evidence of bugs. Im growing in coco loco and using RO water with fox farms tiger bloom/grow big/big bloom at 2/3rds strength every other watering. The RO runs about 7ph. after nutes its down to around 5.5. Then I buffer it up to 6.8 with baking soda gram by gram. Ppm in is about 1500-1800 run off is usually around 1000. Ph is 5.7-6.0. i am stumped as to what I could be doing wrong to cause this. My only diagnosis could be smoke damage from ripping a bong in the same room as the tent?

Ppm in is about 1500-1800

You're overfeeding your plant.

Looks pH related to me. If your nute mix is going in at 6.8 but your runoff is 5.7 to 6 then the root zone pH is way below that. Something sounds off. Ive never used baking soda as a buffer though, personally id get some real pH up and down then flush the coco with plain water balanced at 5.8 until the runoff matches it. Then id start feeding a nute mix at about 5.8 every watering.

Edit: also @xtsho is probably right about overfeeding. I'm that asshole who never measure ppm except when I did DWC so I skimmed right by that. Still think you have a pH issue though.

xtsho said:

Ppm in is about 1500-1800

You're overfeeding your plant.

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According to this chart from fox farms I am technically under feeding slightly.

Gentlemencorpse said:

Looks pH related to me. If your nute mix is going in at 6.8 but your runoff is 5.7 to 6 then the root zone pH is way below that. Something sounds off. Ive never used baking soda as a buffer though, personally id get some real pH up and down then flush the coco with plain water balanced at 5.8 until the runoff matches it. Then id start feeding a nute mix at about 5.8 every watering.

Edit: also @xtsho is probably right about overfeeding. I'm that asshole who never measure ppm except when I did DWC so I skimmed right by that. Still think you have a pH issue though.

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Im due for non nute watering tomorrow I will do a good flush I recently became unemployed and cannot really buy more supplies rn. So vinegar and baking soda are my only real ph.adjusters. i do have a sweet vivo sun lab grade ph / tds probe so I can dial it in pretty well.

BanjoPu$$ywhistle said:

According to this chart from fox farms I am technically under feeding slightly.

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That chart is a joke. Those levels are much too high. I've commented in numerous threads where people fried their plants following that chart. I never go over 1000 ppm the entire grow. And guess what. I never have any nutrient issues. No deficiencies, no burnt up plants, no problems. Just healthy plants from start to finish. The majority of issues people have are caused by overfeeding which can cause nutrient antagonism and pH issues.

ph issues

xtsho said:

That chart is a joke. Those levels are much too high. I've commented in numerous threads where people fried their plants following that chart. I never go over 1000 ppm the entire grow. And guess what. I never have any nutrient issues. No deficiencies, no burnt up plants, no problems. Just healthy plants from start to finish. The majority of issues people have are caused by overfeeding which can cause nutrient antagonism and pH issues.

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Right on man, im new to the game. I figured following the manufacturer would be a safe bet. Im going to flush tomorrow, and then the following watering start at 850-900 ppm

BanjoPu$$ywhistle said:

Right on man, im new to the game. I figured following the manufacturer would be a safe bet. Im going to flush tomorrow, and then the following watering start at 850-900 ppm

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My manufacture recommends 2.4EC that’s 1500ppm.

I feed every day in coco at 1.2-1.4EC that’s about 500-700ppm.

no issues with my plants being fed half their recommended dosage.

I say it time and time and time again.
It’s easier to correct an underfed plant than it is to correct an over fed plant.

UPDATE

I flushed yesterday with 5ppm RO @ 6.2pH. I sampled the run off 4 separate times during the flush. The first run off was 5.2pH and 1100 ppm YIKES!!!!!. I stopped flushing when the run off was 6.1pH and 150-200 ppm. This morning i checked on her after an hour of light and she looked plump, and happy. The picture is what happened during the flush. Anyone ever see the leaves exude liquid like this when watering? Even after I brushed it off, you could watch it bead up with your eyes.

Looking better after some TLC. I think baking soda is causing some salt issues so I ordered some PH up that came today. Baking soda is NOT a stable buffer in coco and hopefully I can not lose too much yield.

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BanjoPu$$ywhistle said:

One was blank

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Do you typically keep your thermometer at the surface of your medium?

My opinion... move your thermometer and hygrometer up where the canopy is. Just a suggestion considering you want to know the temp and humidity at the canopy. It'll help decrease the chance of bud rot or mold during flower

Also... did you get that thermometer combo off of a walk in cooler?

Because I have a 190cfpm vent fan running 24/7 and the tent is only 2x2x3 I figured that it wouldn't matter where I put it do to the amount of air exchange? But maybe thats not a bad idea

BanjoPu$$ywhistle said:

Because I have a 190cfpm vent fan running 24/7 and the tent is only 2x2x3 I figured that it wouldn't matter where I put it do to the amount of air exchange? But maybe thats not a bad idea

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Regardless of air circulation and whether its necessary or not id still rather know my humidity and temp at the canopy... like I said it is only a suggestion

I have an 800w COB LED for one plant also lol. I have it 18 inches from the canopy and its dialed back about 20%