burnt leaf tips and edges

gddg

gddg

Well-Known Member
I'm having issues with brown/ burnt leaf tips and edges and a bit off yellowing in the top of the plants can't figure out what's the cause.

My initial thought was nute burn but my feedings are low strength and runoff also, I don't know if I need to feed them even less or it's something else?

Day 28 Flower
4 gallon coco pot's
temp 86F RH 75%
co2 1250ppm


nutrient's floraflex B1 & B2
EC 1,05 runoff EC 0,95
PH 6,0 runoff PH 6,2

coco22.jpg

coco23.jpg
 
simpleleaf

simpleleaf

Well-Known Member
According to "Cannabis nutrient & deficiencies and excesses" chart: P, K, or S excess, or Cl deficiency may cause burnt tips and edges. Also, lights too close may cause it.
 
gddg

gddg

Well-Known Member
I see some fungus gnats walking and flying around my containers but not in large numbers could they be the reason off the burnt tips? I already watered with nematodes in the coco to kill the larvae and hang yellow sticky traps.
 
HydoDan

HydoDan

Well-Known Member
gddg said:
I see some fungus gnats walking and flying around my containers but not in large numbers could they be the reason off the burnt tips? I already watered with nematodes in the coco to kill the larvae and hang yellow sticky traps.
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No, fungus gnats eat fungus. The larvae can mess with the roots but not burn tips.
 
FlowerPower88

FlowerPower88

Well-Known Member
I have a similar problem, but mine is in veg. It was super close to the light, but the lights are T5s so I didn’t think it could really burn the plant. My feedings are super low, I jumped from 350ppm to 500ppm, so I didn’t think it could be nute burn, I’ve raised the lights and backed off the nutrients, any thoughts?
 
FlowerPower88

FlowerPower88

Well-Known Member
How do I track down the cause, I wouldt think it would be lockout, having been on such a light feeding schedule and being young?
 
VincenzioVonHook

VincenzioVonHook

Well-Known Member
FlowerPower88 said:
How do I track down the cause, I wouldt think it would be lockout, having been on such a light feeding schedule and being young?
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You can still get issues with lockout if your base medium pH is off due to a lack of buffering compounds such as agricultural lime/ dolomite lime. You can do a slurry test on the medium if you want to be sure, but I'd try a foliar of kelp as go go kid suggested or a feed of potassium carbonate and see if it picks up. If you aren't getting any N or P deficiency a foliar or potash drench will do the job.

Are you using a rounded base nutrient? Usually potassium deficiency doesn't show up until flower stretch has finished.
 
Nutty sKunK

Nutty sKunK

Well-Known Member
VincenzioVonHook said:
potassium deficiency. usually shows up as burnt tips and serrations. Usually followed by yellowing. Now to figure out why its deficient in K.. Could be lockout/PH or could be lack of K.
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Although K is mobile so that happens on the lower leaves first. Can’t see any lower leaves in those pics so tricky to tell.

Excess K is shown in the youngest leaves first tho!

Just looks like light nute burn to me…
 
VincenzioVonHook

VincenzioVonHook

Well-Known Member
Nutty sKunK said:
Although K is mobile so that happens on the lower leaves first. Can’t see any lower leaves in those pics so tricky to tell.

Excess K is shown in the youngest leaves first tho!

Just looks like light nute burn to me…
Click to expand...
Tbh the three times I've got a big K deficiency it hit the leaves on the top colas before anything else. Pretty much all the lower leaves were fine. Tops ended up looking like this. Bottoms just had burnt tips.
IMG_20220126_083118.jpg
IMG20210711103820.jpg
IMG20210713152316.jpg

The lower you go down the colas, the better the leaves got. It confused me for sure. Feeds of potash generally Greened the leaves back up but didn't get rid of the necrosis obviously. Most of the potassium deficiencies I have seen had a general yellowing over the top of the colas, but I have only grown like 10 plants so I'm pretty green here.

To be fair, there was probably more than just K deficiency with mine though.
 
FlowerPower88

FlowerPower88

Well-Known Member
VincenzioVonHook said:
You can still get issues with lockout if your base medium pH is off due to a lack of buffering compounds such as agricultural lime/ dolomite lime. You can do a slurry test on the medium if you want to be sure, but I'd try a foliar of kelp as go go kid suggested or a feed of potassium carbonate and see if it picks up. If you aren't getting any N or P deficiency a foliar or potash drench will do the job.

Are you using a rounded base nutrient? Usually potassium deficiency doesn't show up until flower stretch has finished.
Click to expand...
Yes I’m using Floraflex V1/V2…no cal mag because Floraflex says not to use because it is already a part of the base nutes
 
FlowerPower88

FlowerPower88

Well-Known Member
Nutty sKunK said:
Although K is mobile so that happens on the lower leaves first. Can’t see any lower leaves in those pics so tricky to tell.

Excess K is shown in the youngest leaves first tho!

Just looks like light nute burn to me…
Click to expand...
The lower leaves have no burn on them, when I first got the clone it got nute burn pretty good, not extreme but bad enough…took a couple weeks but bounced back, that time the lower foliage got burned tips and clawed etc. the last 2-3 weeks have been uneventful, but all of a sudden I have this similar but not as wide spread or severe burning only on the very top nodes…there are some fan leaves at the bottom with burnt spots from the initial burn a month ago…here are some better pictures.
 

Attachments

Nutty sKunK

Nutty sKunK

Well-Known Member
VincenzioVonHook said:
Tbh the three times I've got a big K deficiency it hit the leaves on the top colas before anything else. Pretty much all the lower leaves were fine. Tops ended up looking like this. Bottoms just had burnt tips.
View attachment 5116991
View attachment 5116992
View attachment 5116994

The lower you go down the colas, the better the leaves got. It confused me for sure. Feeds of potash generally Greened the leaves back up but didn't get rid of the necrosis obviously. Most of the potassium deficiencies I have seen had a general yellowing over the top of the colas, but I have only grown like 10 plants so I'm pretty green here.

To be fair, there was probably more than just K deficiency with mine though.
Click to expand...
Interesting!

I guess we forget these plants vary so much from one another there’s a massive spectrum of what each one needs. Or even how they express certain deficiencies.

Get 3 strains and give them all cal def it looks similar but can vary from plant to plant.
 
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