Yellowing Leaves Early in Flower

Have a troublesome grow indoors. First grow since 2014. Did 2 dry runs with 6 inch plants through flower. Seeds were from 2010 black market cannabis. Plants looked perfect the entire way. In fact lower leaves didn't yellow at all through to harvest, but they were tiny plants in 2 gal containers.

I started some plants from a seed bank. Bubblegum and Super Skunk. Grew them mostly outdoors in soil for the first several weeks. (It was a bad situation because, while my black market plants were all the same size, as with every grow I've done, these expensive seeds weren't. All different rates of growth in the same environment.)

Eventually transplanted the bubblegum (4 plants) and super skunk (2 plants) from soil to coco to grow outside in an extremely hot environment (Average 110F for two weeks x 2 episodes). Plants were transplanted to 10 gallon containers prior to the high heat assuming they would finish outdoors and so I could water heavily during the hot spells. Plants had one episode of yellowing leaves outdoors, possibly due to a phosphorus deficiency caused by too much sun) that appeared to be remedied by strict control of PH (5.8) and adding Flower Fuel (1-34-32) to the VPS products I was using at the time.

Unfortunately one super skunk and one bubblegum started flowering a few days after the longest day of the summer (with over 14 hours of light every day), and a month before I thought they would start, so, because of our monsoon season and knowing bubblegum molds, I moved all 6 plants indoors.

Now the plants are in a 4x4 in 10 gallon containers. Using a VS KS5000. About 12 inches off the canopy and set to 100%. PPFD is over 1000. Plants were trained to create a horizontal canopy and even though I lollipopped, the canopy is still thick, but light is reaching leaves that are now turning yellow, where as a week ago only leaves way down in the canopy were yellowing, and that appeared to be from a phosphorous deficiency.

When I started noticing a possible phosphorus deficiency fairly quickly in the tent, I added Flower Fuel to VPS again (PH 6.0) and fed that for 3-4 feedings. Nothing changed really, except the leaves didn't appear to have the previous brown spots on yellowing leaves.

As mentioned above, now I have leaves receiving light that are yellowing, but the latest leaves do not appear to have a phosphorus deficiency. Looks more like it might be a nitrogen deficiency. All 6 plants are at a different stage of development. One Super Skunk appears to be in about week 5 and the first to flower Bubblegum looks a week younger. The rest are in weeks 2-3.

So, before I loose this crop after all the work of getting them this far, thought I would ask for help. I did turn down the KS5000 to 75% to see if that would help. PPFD is around 600 to 800.

Added Co2 via wine yeast and sugar water a couple days ago. Do not have a CO2 meter to measure CO2.

Do not have pictures. Will take some when lights are on again.
 

Rahz

Well-Known Member
When I have had leaf problems like that I can usually fix it with a heavy flush and re-water. I've plugged up the sink after the flush, over water and adjust PH directly in the runoff, cycle through the runoff and check again. Keep adjusting runoff until it's the same going out as coming in at your ideal PH. Depending on the soil, what you're feeding, etc. the PH can get very low and adding properly PHed nutrients on top isn't going to raise it up enough. Conversely, I've had situations where the PH through normal watering ended up around 6.7 for what reason I don't know... but a heavy flush with a careful PH afterwards will take care of salt buildup and PH issues. I've had sorry looking plants perk up quickly doing this.
 
The PH above is 5.8.

Also want to add I've been strictly managing VPD to the pulse VPD chart. Temps lights on 80-83. Humidity slightly over 60 with lights on. Lights off 74-79, humidity ~58%.

I do have old pictures. My camera date is off by a year. Spare phone.

7/21/2022
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7/26/2022

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7/28/2022

20210728_055341.jpg

8/5/2022

20210805_053627.jpg
 
When I have had leaf problems like that I can usually fix it with a heavy flush and re-water. I've plugged up the sink after the flush, over water and adjust PH directly in the runoff, cycle through the runoff and check again. Keep adjusting runoff until it's the same going out as coming in at your ideal PH. Depending on the soil, what you're feeding, etc. the PH can get very low and adding properly PHed nutrients on top isn't going to raise it up enough. Conversely, I've had situations where the PH through normal watering ended up around 6.7 for what reason I don't know... but a heavy flush with a careful PH afterwards will take care of salt buildup and PH issues. I've had sorry looking plants perk up quickly doing this.
Thanks
They don't look that bad. Runoff PH is 5.8?
I'm in coco coir so I am now PH'd at 6.0 to 6.2, but mostly 6.0. I can't water till runoff. Too crowded. 10 gallon containers. And I've read runoff in coco coir is unnecessary, but first time using coco coir, so I don't know for sure.
 
Thanks


I'm in coco coir so I am now PH'd at 6.0 to 6.2, but mostly 6.0. I can't water till runoff. Too crowded. 10 gallon containers. And I've read runoff in coco coir is unnecessary, but first time using coco coir, so I don't know for sure.
What I meant was I read measuring runoff PH in coco coir is unnecessary. But I can't. Too much volume at 10 gal.
 
Every soil PH probe I've used was shit. I've never used straight coir so I can't comment on using it.

Maybe someone else can comment on the pics, but they don't look that bad.
Thanks!

Actually it's a 50/50 coco perlite mix. That was to water heavily while outside.

I'm not using a soil PH meter. I just measure the feeding liquid at 6.0 now that I'm in flower.

Recommendation online for coco: 5.8 veg. 6.0 to 6.2 flower.

Thanks again!
 
runoff is generally needed to dissolve salt buildup. you can measure the runoff EC vs feed EC to get an idea of what's going on should a problem arise, but 10 gallons of coco is nutty! I can't imagine hand watering all that! the plants look ok though? I'm sure they can handle 1k ppfd.
 
runoff is generally needed to dissolve salt buildup. you can measure the runoff EC vs feed EC to get an idea of what's going on should a problem arise, but 10 gallons of coco is nutty! I can't imagine hand watering all that! the plants look ok though? I'm sure they can handle 1k ppfd.
Okay. Thanks!

Question: bought a vivoson combo EC/PH/? meter. Cal was too screwed up and comments online validated that.

Recommendation for an EC meter?

TDS has shown between 500-1000 depending how much flower fuel I use.

Also should I be adding flower fuel 1-34-32 to VPS nutrients? Is it too much P/K? Using it at half dose.

Thanks!
 
Okay. Thanks!

Question: bought a vivoson combo EC/PH/? meter. Cal was too screwed up and comments online validated that.

Recommendation for an EC meter?

TDS has shown between 500-1000 depending how much flower fuel I use.

Also should I be adding flower fuel 1-34-32 to VPS nutrients? Is it too much P/K? Using it at half dose.

Thanks!
I use this one as suggested by cocoforcannabis: https://www.amazon.com/Lxuemlu-Professional-Temperature-0-9999ppm-Aquariums/dp/B079DN9DRS

though, if you have a TDS meter and it is using the 500 scale, you can just multiply it by 2x and that is your EC i.e. 500ppm = 1000ec or 1.0ec

I am not familiar with VPS nutrients, but varying the feed by 500ppm is highly unstable and can cause problems.

This is a rough guide for EC / ppm targets which you might find useful. The whole website is super informative.
 
I use this one as suggested by cocoforcannabis: https://www.amazon.com/Lxuemlu-Professional-Temperature-0-9999ppm-Aquariums/dp/B079DN9DRS

though, if you have a TDS meter and it is using the 500 scale, you can just multiply it by 2x and that is your EC i.e. 500ppm = 1000ec or 1.0ec

I am not familiar with VPS nutrients, but varying the feed by 500ppm is highly unstable and can cause problems.

This is a rough guide for EC / ppm targets which you might find useful. The whole website is super informative.
Thanks! So maintain stable at what TDS value? Whatever VPS tells me to use? Thanks!
 
Thanks! So maintain stable at what TDS value? Whatever VPS tells me to use? Thanks!
hard to say. nutrient manufacturers usually jack up feed suggestions. go with what the plants look happy with. the feed chart I linked has ppm targets for each stage of growth that you can use as a rough estimate.
 
hard to say. nutrient manufacturers usually jack up feed suggestions. go with what the plants look happy with. the feed chart I linked has ppm targets for each stage of growth that you can use as a rough estimate.
Thanks. Did not look at the link yet. Got distracted. I have no leave burn. I'll call VPS for suggestions too. Thanks!
 
When I have had leaf problems like that I can usually fix it with a heavy flush and re-water. I've plugged up the sink after the flush, over water and adjust PH directly in the runoff, cycle through the runoff and check again. Keep adjusting runoff until it's the same going out as coming in at your ideal PH. Depending on the soil, what you're feeding, etc. the PH can get very low and adding properly PHed nutrients on top isn't going to raise it up enough. Conversely, I've had situations where the PH through normal watering ended up around 6.7 for what reason I don't know... but a heavy flush with a careful PH afterwards will take care of salt buildup and PH issues. I've had sorry looking plants perk up quickly doing this.
Hey Rahz, Called VPS. Talked to a 12 year grower. Said to flush those 10 gallons, period, and adjust nutrients by plant. Like add extra cal mag due to coco and nutrient lockout. Wish I'd used 5's. Or 2's. ROFL.
 

Rahz

Well-Known Member
Yea, I haven't done as much soil as hydro but I did learn that a flush can make a huge difference. I did it mid flower for every plant but over time I learned to change the PH of the nutrient solution so I didn't need to flush. It's going to vary by soil brand, nutes, etc. but over time you can get to the point where there's no need to flush.
 
Yea, I haven't done as much soil as hydro but I did learn that a flush can make a huge difference. I did it mid flower for every plant but over time I learned to change the PH of the nutrient solution so I didn't need to flush. It's going to vary by soil brand, nutes, etc. but over time you can get to the point where there's no need to flush.
First time coco perlite 50/50. Usually FFOF, but fungus knats galore indoors. Growers house recommended 50/50 because I was outside in ~100+F. Turned out to be 110+F this summer. Typically grow Oct to Feb in my climate.

I need to get into cannabis whisperer mode.

THANK YOU so much for your time! I'm flushing tonight.
 
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