Poorly Plants - yellowing curly top leaves, lower leaves dropping off

[Cheekyleener]

I've encountered a problem with my girls just coming into week 4 of flowering.

Growing 5 autoflower Girl Scout Cookies in a BudBox Pro tent with 600W LED light and growing in coco coir with 30% perlite mix.

One of the plants started showing yellowing and curling tips on the top fan leaves and the lower fan leaves were wilting and dropping off. Over the past couple of days this has started to show on 2 of the other plants.

I took the runoff pH from the first plant, which came back as 5.13 (too low). I then flushed with with pH 6.2 water to try and correct until runoff was pH 5.8 and then gave a feed with Cal Mag, Canna A & B and Great White mycorrhizae (normal dose of each). I checked for root rot but no bad smell or brown roots, just very thin white ones.

I did a slurry test on a second plant that was showing similar symptoms this morning and came back with a pH of 5.11.

I have successful grow experience on 6 grows but have never encountered this problem before.

I suspect that it is Potassium deficiency caused by salt buildups, probably through not feeding enough to each plant when it's feeding time (every 2-3 days) but would appreciate advice from more experienced growers on what the problem is and the best way to resolve it.

Photos attached are Plant A (the one I flushed and with the most extreme problem), Plant B (the one I slurry tested this morning) and C (the largest plant that is just beginning to show brown curling tips). All three have had lower fan leaves wilt and drop off (a couple of examples shown in the last 2 pics).

I added a dose of Canna PK 13/14 to the normal feed mix just before the problem showed itself but I don't know if this is just coincidental?

I'd be grateful for any advice and I'm happy to provide any more info that I've missed out.

 

[Bill284]

I've encountered a problem with my girls just coming into week 4 of flowering.

Growing 5 Girl Scout Cookies in a BudBox Pro tent with 600W LED light and growing in coco coir with 30% perlite mix.

One of the plants started showing yellowing and curling tips on the top fan leaves and the lower fan leaves were wilting and dropping off. Over the past couple of days this has started to show on 2 of the other plants.

I took the runoff pH from the first plant, which came back as 5.13 (too low). I then flushed with with pH 6.2 water to try and correct until runoff was pH 5.8 and then gave a feed with Cal Mag, Canna A & B and Great White mycorrhizae (normal dose of each).

I did a slurry test on a second plant that was showing similar symptoms this morning and came back with a pH of 5.11.

I have successful grow experience on 6 grows but have never encountered this problem before.

I suspect that it is Potassium deficiency caused by salt buildups, probably through not feeding enough to each plant when it's feeding time (every 2-3 days) but would appreciate advice from more experienced growers on what the problem is and the best way to resolve it.

Photos attached are Plant A (the one I flushed and with the most extreme problem), Plant B (the one I slurry tested this morning) and C (the largest plant that is just beginning to show brown curling tips). All three have had lower fan leaves wilt and drop off (a couple of examples shown in the last 2 pics).

I added a dose of Canna PK 13/14 to the normal feed mix just before the problem showed itself but I don't know if this is just coincidental?

I'd be grateful for any advice and I'm happy to provide any more info that I've missed out.

Hey @Cheekyleener hope you are well my friend.
sorry about your issues.
Welcome to 420magazine.

Are you following the schedule for your nutrients, full strength ?
Are you putting calmag in first waiting 10 minutes then adding the rest ?
Then setting the ph to 5.8 very important.
Do you feed every day to run off ?
Do you have a ppm pen ?
Coco needs to be kept wet at all times and no plain water ever.
Concentrate on what is going in. Do that right.
Don't worry about runoff at the moment.
You will end up chasing your tail in circles.

Thanks Amigo, talk soon.

Stay safe
Bill

 

[Cheekyleener]

Hey Bill

Thanks for your response.

I'm following my nutrient schedule (all full strength atm) but put the cal mag in with the general nute mix rather than separately. I think I may also have added the PK 13/14 before the plants were ready for it.

ph of the feed varies between 5.8 to 6.4 (generally over 6.0) but I've not been feeding to runoff each time and not feeding every day.

I have got a ppm pen but this grow is the first time I've used it so still learning! I measured the filtered liquid from the slurry test today and the EC was 2164, which I think is a bit high.

Thanks

 

[Bill284]

Hey Bill

Thanks for your response.

I'm following my nutrient schedule (all full strength atm) but put the cal mag in with the general nute mix rather than separately. I think I may also have added the PK 13/14 before the plants were ready for it.

ph of the feed varies between 5.8 to 6.4 (generally over 6.0) but I've not been feeding to runoff each time and not feeding every day.

I have got a ppm pen but this grow is the first time I've used it so still learning! I measured the filtered liquid from the slurry test today and the EC was 2164, which I think is a bit high.

Thanks

Ok no big problem yet, quite fixable by changing your routine a little.
First calmag into just plain water, let it mix for 10 minutes.
This will let the calmag help feed your girls.
It helps with nutrient uptake aswell as providing Cm that coco will remove from you ladies.
So improper mixing can cause a def.
Second ph is very important in coco.
The avaliable nutrients are in a small window if you change ph it makes certain nutrients unavailable to the roots for pickup.
So that number 5.8 isn't a suggestion it's a vital component of proper nutrient uptake.
Third coco is hydrophobic, go figure right it doesn't like water.
So once you soak it you have to keep it wet at all times.
What happens is when it dries a little it starts to repel water.
So you need twice as much to get it wet again.
So you think you are watering but it just shoots through the pot and out the bottom.
So water it every day to run off.
Some strains in flower require 2-3 feedings per day.
Also if you don't water to run off you get a build up in the root zone of left over salts, etc.
Daily watering to run off prevents this from happening.

I would flush the pot to remove build up first thing.
3x the size of the pot. Do it in a sink or tub for ease.
Then immediately feed full strength nutrients mixed properly at 5.8.
Then feed daily full strength as I described.
Your mix will be in the 900 to 1200 ppm ish when mixed properly according to the schedule.
Then feed daily to run off proper nutrients all the way to harvest.
If you get a chance start a journal and I can follow and help.

Grow Journals

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www.420magazine.com

Stay safe
Bill

 

[Cheekyleener]

Thanks for the advice Bill.

I'll do as you suggest and let you know how things go