Help with diagnosis

Hey guys. I'm alright at picking glaring issues when I get them, but useless at catching things early on.

Over the last two-three days I've had fast onset yellowing and burnt tips. I'm thinking a minor potassium issue due to the burnt tips, but the fact that's it's only the top fan leaves makes me think it's some type of mobilisation issue.

Here's where it gets difficult. I'm using $4 osmocote prills and yard soil lol. The oscmotic prills are 8:4:10, and there is 2tbsp in a 5gal pot. Tap water until now only (7.6/200ppm)

It's sandy loam from a mates yard, there is a tbsp each of Gypsum, basalt and glacial dust in there alongside some vermicompost and perlite (10L yard soil, 5L vermicompost and 5L perlite). pH of slurry is coming back at 6.3, which has dropped a bit over the last few weeks from 6.6.

What do you guys reckon, a bit hungry, or the beginnings of some type of immobilisation/lockout issue from osmotic prills? I have 1-1-2 bloom boost, 9-2-8 liquid compost and some Canna Coco here, bit I don't want to compound anything yet.

can't flush salts out either if it's building up from the osmocote out as it feeds every time I water lol.

Three days ago

Today


I used this slow release last run and had no yellowing, but the plant was smaller (like 2 Oz and 45cm). It did end up with calcium issues in flower (rust spots on top fans and slight tip burn on top leaves), and I look to have that starting on the top fans now as well by the looks of the mottling.

What do you reckon, hungry or issue?

Looks like some nute burn but could also be light stress..

HydoDan said:

Looks like some nute burn but could also be light stress..

Click to expand...

Come to think of it, I just lowered the light from 21 to 16" a few days ago. Could have something to do with it. Probably eating a bit more now.

Right, so I'm still stumped as the top leaves are fading and I want to try and catch it before it gets to be an issue...looks like potassium to me due to the tips and burnt serrations. The lower you go, the better the leaves get though which is odd.

I shouldn't be getting light stress as I've reduced the lighting to 135w, I'm at 38-42k lux at the main tops effected and around 25k for the rest of the canopy. Running the light 16 hours I should be getting a pretty mediocre DLI, but it's just strange that it's only the top fans on the main colas going.

I don't want to feed it any more if it is burn, and the fact that the bottom leaves are A1 is leading me to think that it's lockout from the osmotic prills..

What do you guys think from these pics? The first one looks like potassium deficiency to me, but usually I get it on the lower leaves as well.



Notice the bottom leaves are fine


A few people.ive had check at home, and online have leaned towards light stress but I'm just not convinced, as if I lower it below 35k at the tops, it'll only be getting like 15k over most of the middle canopy.

Slurry pH still coming out at 6.3-6.4. runoff coming out pretty radioactive, but being osmotic I can't really flush.

I'm probs just blowing shit out of proportion lol. Just find it odd that every leaf in direct light has nute burn/potassium symptoms, and all the lowers are dead perfect.

The amnesia in the same medium is going good but it's earlier in flower

Funny though as I always seem to get this exact pattern during flower. Have had it three times now out of like six runs. Bottom leaves fine, top leaves potassium burn to the shit house..

Those were in Coco/perlite as well, but the exact same symptoms, and these are starting to look identical.

Looks like light stress to me on your current run. Your meter and your plant do not seem to agree as to light intensity. The second group of pics look like some kind of lockout perhaps from over feeding.

Trying to use time release fertilizer
Too hot early causing lockout isn’t surprising

pretty much as I expected lockout wise. Just wanted some confirmation that it wasn't hungry before i fed it anything lol. The top leaves going first was a pretty good giveaway that something is awry.

It's always in the back of my mind when you've fed tap water for eight weeks.....just lingering..."i wonder if shes hungry"

Highway61 said:

Looks like light stress to me on your current run. Your meter and your plant do not seem to agree as to light intensity. The second group of pics look like some kind of lockout perhaps from over feeding.

Click to expand...

The second group of pics was defo a serious case of lockout. They were both going well until about week 6 of flower and they just stopped eating. Was putting 800 though daily and getting a steady 850-900 runoff for a few weeks and bang. Over a few days the runoff randomly jumped up to 1800-1900 and they just stopped eating.

The current one though, I was hesitant to accept light stress for no apparent reason bar my readings being okay.


I'll try raise the light until the tops are getting 30-35k (down 5-8k) and see if it does help a bit. I've been trying not to go under 135w so far as it's pretty cool in there (like 20c at pot level and 25c at canopy so I need the heat). The leaf temps were only 22c last time I checked which is probs a bit low too.

Makes sense though as if the medium is a bit hot or locking out, the dli accumulation would naturally speed up the plants metabolism and cause it to demand more.

All in all it's still fattening up well still so I'm not going to stress too much.

Looks like mag def. and nute burn.. the red stems along with the leaves indicate a magnesium problem.. also the dark green leaf edges with slight fading i between the veins..
Or maybe phospherous too..

farmerfischer said:

Looks like mag def. and nute burn.. the red stems along with the leaves indicate a magnesium problem.. also the dark green leaf edges with slight fading i between the veins..
Or maybe phospherous too..

Click to expand...

Gave it a TSP Epsom to 2L yesterday and there seems to be green coming back to the leaves which is a surprise. Thought it was toasted....well it still is by the looks of it, but the green is coming back at least.