Yellow leaves with brown spots in Flower

[Michael49]

Your problem looks like it has gone away, your newer growth is healthy and green.
Those older damaged leaves all need to be removed, once in that condition they will never improve and just take away energy from the plant. When you cut away all those crappy leaves, your plants will look just fine. Don't overfert and add a little calmag in a couple weeks from now.

Thanks for your input, the new growth always seems to look good, but then the mature fan leaves start keep dying .

Sure looks like a phosphorus deficiency...

Anyone else agree with this assessment?

Something I found with a closed room at night is that high humidity during lights out can make temps stay much lower than they should be.

I remember a case when night temps in a closed room would always be 5-8 degrees colder than rest of rooms in house. . . put a dehumidifier in during lights out, and viola, temps jumped up above 70 degrees.

That's interesting.

My humidity during lights on is very low (25%) because its so damn cold outside here!! - but at night once my lights and exhaust fan go off the humidity rises to like 70% inside the tent.

I toyed with the idea of leaving my exhaust fan on during lights off to keep the humidity lower but I was worried that would only drop temps even more - what do you think? During lights off my tent has very little ventilation.

 

[Michael49]

The give away on a P deficiency on this leaf is the fact that the strong chlorosis does not obey the veins. Phosphorus is the only element that will do this. Most everything is margins, interveinal, etc. I would also bet you would see a big response to some micronutrients like Mn for example. Again, do one branch and watch what happens.

A good one to confirm positive response is to test petioles, after washing of course, with a refractometer. If the plant got a response, the brix will increase, in about 24 hours or so.

Also, if the P response shows up, that branch will start praying heavy.

Experiment my friends!

Thanks!!

 

[Ready4]

Also vegging in that size pot, for as long as you did ( 6 weeks), could have serious problems with very rootbound plants, possibly causing nutrient problems.
Blueberry & crosses I have done were sensitive to N, but really loved Calmag.
No matter what you add, it will take time for any effect to show.
Best of luck !

 

[geneva_sativa]

Might be worth a try. . . especially if you have one of those $10.00 digital thermometers that can tell you the low and high temps during last 24 hours, so you can know what temps are doing during lights out.

 

[Wendull C.]

Listen to slow, the reason the new growth looks good and the lower fans are showing the deficiency is you are dealing with mobile nutrients in the deficiency. The plant eill rob the lower growth of nutes to feed the growing tips. Just a bro science thing but i would foliar feed them with insta green or foliage pro while upping the phosphorus like slow said. That guy is a soil wizard. What he says is gospel to me and the books he recomends are top notch. I just wish i was further than skimming pages when im bored.

 

[Wendull C.]

The give away on a P deficiency on this leaf is the fact that the strong chlorosis does not obey the veins. Phosphorus is the only element that will do this. Most everything is margins, interveinal, etc. I would also bet you would see a big response to some micronutrients like Mn for example. Again, do one branch and watch what happens.

A good one to confirm positive response is to test petioles, after washing of course, with a refractometer. If the plant got a response, the brix will increase, in about 24 hours or so.

Also, if the P response shows up, that branch will start praying heavy.

Experiment my friends!

Bam! SOIL WIZARD! Bettet hope the real farmers dont come around too quick. Put all us bro science guys out in the cold, lol.

 

[Michael49]

Listen to slow, the reason the new growth looks good and the lower fans are showing the deficiency is you are dealing with mobile nutrients in the deficiency. The plant eill rob the lower growth of nutes to feed the growing tips. Just a bro science thing but i would foliar feed them with insta green or foliage pro while upping the phosphorus like slow said. That guy is a soil wizard. What he says is gospel to me and the books he recomends are top notch. I just wish i was further than skimming pages when im bored.

Thanks!!

 

[Michael49]

Also vegging in that size pot, for as long as you did ( 6 weeks), could have serious problems with very rootbound plants, possibly causing nutrient problems......

Anyone think I should do anything for the roots, like some Hydroguard or do you think my roots are likely to be OK?

 

[slownickel]

Anyone think I should do anything for the roots, like some Hydroguard or do you think my roots are likely to be OK?

If you think they are potbound, some gypsum is probably in order. The first limitation will be calcium and when calcium is deficient, everything else can go deficient as a result.

 

[RB56]

Something I found with a closed room at night is that high humidity during lights out can make temps stay much lower than they should be.

I remember a case when night temps in a closed room would always be 5-8 degrees colder than rest of rooms in house. . . put a dehumidifier in during lights out, and viola, temps jumped up above 70 degrees.

Dehumidifiers produce heat.

 

[geneva_sativa]

Thanks, RB56. . .heh heh

Guess that would explain the magic numbers !

 

[calisun]

I would suggest a light phosphorus feed, say 0.5% phosphoric acid. Do it light on one side of a plant, on one branch. That is how you learn.

I have a old bottle of advancing nutrients ph down. The label is worn out but I think it is pure pharmaceutical grade phosphoric acid. My concern is it is so strong, with about 1/4 oz will drop the ph of a 50 gallon barrel about a point.I Would need to then ph up my soluition before use. Is there a better source of phosphoric acid? Thanks

 

[Michael49]

I have a old bottle of advancing nutrients ph down. The label is worn out but I think it is pure pharmaceutical grade phosphoric acid. My concern is it is so strong, with about 1/4 oz will drop the ph of a 50 gallon barrel about a point.I Would need to then ph up my soluition before use. Is there a better source of phosphoric acid? Thanks

I thought of this myself (it's the only source of phosphoric acid I have) but i've no idea how to dilute it appropriately to use for foliar feeding.

 

[Michael49]

I ran my exhaust fan during lights out for the first time last night. It didn't raise my temp at all (59 degrees low) but it did drop the lights out humidity to 35% from about 70%.

 

[slownickel]

Take what ever phosphoric acid you have, measure 0.5% of it into water. Spray. Don't pH it as it will either burn the sensor or freak you out, hahaha.

Try one leaf so as not to take any risk. Never do anything without trying it in a small way.

(5 ml in 1000 ml of water) oh you guys are freaking, I can feel it. No ph down either. The pH will be close to 2.5 or so. Please stop freaking! Easy's fault. My last bit of diamonds.... rrrrrr

https://www.icmag.com/ic/showthread.php?t=331317&page=348

This is the page where we have been through the phosphoric acid foliar issue at this same dose before, for those that don't know this thread. I imagine you could go to at least 2% in veg, but I HAVE ONLY ever applied 0.5% in this crop. Jidoka applied even more after his first experiment, hahaha but I can't get him to say how much, it did go to 0.5 pH though. Must have been a bunch!

 

[Cannabologist]

Thanks for your input, the new growth always seems to look good, but then the mature fan leaves start keep dying .

You are suffering a host of deficiencies likely caused by nutrient lockout....

Yellowing from bottom up, leaf veins reddening from the petiole, is nitrogen, which comes along with calcium, which is rust spots on veins, and magnesium, also yellowing, but also curling up of the leaf margins, and mg alone you will see no red pigmentation of the major leaf vein.
Potassium leaf tips curl down, and will brown/grey, die.

Iron starts at the top of a plant as yellowing. It is quite uncommon but mistaken for N deficiency.

Nute burn your tips turn yellow, brown, and curl up.

dot dot dot.

You have all of this pretty much. lol

https://www.icmag.com/ic/showthread.php?t=336296

This is your key. To deficiencies that is. Follow that key..


3 gallons in fab pots for 6 weeks is too long FFOF lasts prob 3 weeks from a transplant. Idk about that roots nute, I would stop ph'ing it firstly. Sounds cray, but that's what I'd first do if I didn't first first toss it and get something else.
Secondly youre overfeeding and prob overwatering. Feed once maybe 2 times a week. Their schedule calls for 5 mls per gal I'd go with that. But right now don't feed anything let it dry out and just water. Don't go nuts just water it when it needs it. Humic, fulvic acids, kelp, and amino acids can help get things going again. Give it like 3 or 4 days to work itself out see where things are at then maybe on the next watering you can give it 5 mls again but I'd go with different nutes like, gh's 1 part nova or cocotek, something easy cheap and works. Not that aurora doesn't but you're obv doing something wrong sorry to say. A product like optic foliar spray on those leaves would help revitalize the plant. Other products like revive as well.
Id also throw it all away and start again lol. But don't take my opinion.

 

[hyposomniac]

Take what ever phosphoric acid you have, measure 0.5% of it into water. Spray. Don't pH it as it will either burn the sensor or freak you out, hahaha.

Try one leaf so as not to take any risk. Never do anything without trying it in a small way.

(5 ml in 1000 ml of water) oh you guys are freaking, I can feel it. No ph down either. The pH will be close to 2.5 or so. Please stop freaking! Easy's fault. My last bit of diamonds.... rrrrrr

https://www.icmag.com/ic/showthread.php?t=331317&page=348

This is the page where we have been through the phosphoric acid foliar issue at this same dose before, for those that don't know this thread. I imagine you could go to at least 2% in veg, but I have only ever gone this far in this crop. Jidoka applied even more after his first experiment, hahaha

I like the new sig, it's a favorite of mine.
The first time I saw you recommend this spray, I thought you were pranking Jidoka.
I have since done it and can confirm that this won't dissolve your plants into a pile of goo

 

[slownickel]

I like the new sig, it's a favorite of mine.
The first time I saw you recommend this spray, I thought you were pranking Jidoka.
I have since done it and can confirm that this won't dissolve your plants into a pile of goo

Great! No goo is good.

Any positive response?

 

[hyposomniac]

Great! No goo is good.

Any positive response?

Yes.. positive response.
after my scary soil test w the really high iron...and then replanting into fresh mix, while the roots rebuilt., P sprays, alternated with Ca/mn/zn/b spray and the plants really recovered, even while the rootzone was suffering ptsd.
They got frazzled pretty good by that iron overload, but I do believe we will have a decent harvest.
Working on a thread soon for the new soil build.
PS I think I figured out how all that iron and nitrate got into the mix.. it was a bag of blood meal that leached into my other shit.

 

[Michael49]

Thanks for your input, the new growth always seems to look good, but then the mature fan leaves start keep dying .

You are suffering a host of deficiencies likely caused by nutrient lockout........

.....3 gallons in fab pots for 6 weeks is too long FFOF lasts prob 3 weeks from a transplant. Idk about that roots nute, I would stop ph'ing it firstly. Sounds cray, but that's what I'd first do if I didn't first first toss it and get something else.
Secondly youre overfeeding and prob overwatering. Feed once maybe 2 times a week. Their schedule calls for 5 mls per gal I'd go with that. But right now don't feed anything let it dry out and just water. Don't go nuts just water it when it needs it. Humic, fulvic acids, kelp, and amino acids can help get things going again. Give it like 3 or 4 days to work itself out see where things are at then maybe on the next watering you can give it 5 mls again but I'd go with different nutes like, gh's 1 part nova or cocotek, something easy cheap and works. Not that aurora doesn't but you're obv doing something wrong sorry to say. A product like optic foliar spray on those leaves would help revitalize the plant. Other products like revive as well.
Id also throw it all away and start again lol. But don't take my opinion.

Thanks for the input.

Its difficult for me to believe I'm overwatering - at this point I'm watering about every 4-6 days.

And I don't think I'm overfeeding as I'm typically only feeding once/week at most.

Why should I stop pH'ing my water?

I might try the Optic foliar spray.