HELP! Brown spotty leafs, really need your support

[PaulV]

Hi everyone

I've got a serious problem with my babies, as u can see from my pix, they develop tiny brown spots on their lower leaves, these then spread and are accompanied by yellowing as well as drying out and crisping. They also seem to be stunted in their growth. This affects all my 3 plants, white widdow and ak47... I have just flushed them with plain pH water. But I'm not sure if this is just a simple nute burn or a deficiency, I just can't figure it out and don't want to make a serious mistake. I'm using biobizz nutrients, biobizz grow as macro and biobizz heaven as micro, I feed every second watering at half the recommended strength with added calmag at recommended strength.

I know the pixs are not the greatest but I hope someone is able to help.
Please see set up below:

COCO+perlite, ak 47 and white widdow(photoperiod) , 120x60x60 grow tent, 4inch exhaust and filter, clip on fan, 450w viparspectra led, biobizz grow+heaven(nutrients), calmag, average temperature 22C, average humidity 40%

[BR2K]

I am pretty certain one of the major players will chime in...I performed a quick search on GWE: https://www.growweedeasy.com/cannabis-symptoms-pictures

[PaulV]

Thanks bud, I hlreally hope one of the pros can give me some advise, otherwise I fear I will have to start again. Maybe I buy some better known nutrients for the next try.
I just can't get my head around this and it's super frustrating as I'm generally a pretty decent gardener but it looks like I'm too stupid for this..... So sad!

Anyway thanks in advance for any input and help

[FlyingDutchPaddy]

hey PaulV ,

i had a closer look at the pics, and i'm betting on a phosphorus deficiency.
https://www.growweedeasy.com/cannabi...rus-deficiency

what are the NPK of the nutrients you're feeding, and how much of each?

FDP

[FlyingDutchPaddy]

someone that actually grows in coco perlite may correct me here, please do!

i remember reading a while back that coco had to be prepared for a while before starting a grow...
something about calcium/phosphorus ,if unprepared, availability i think.

[PaulV]

Thanks FDP

Im using biobizz grow which I believe is not very well known. NPK is 4-3-6, I'm using 1/2 ml per Liter, recommend dose is 1-2ml/l and I water with pH water only + calmag every second watering. My calmag also contains a little nitrogen (1.8-0-0), again I use calmag with every watering. I'm using tap water which I believe I quite hard in my region. The girls are about 4 weeks old now so way too small for their age.

I ph test my water every time and lower to 5.5 - 6.5.

I have definitely made the following mistakes so far although I'm not sure how serious they are:

My pH meter was a little off by 0.4, this is now corrected

I have slightly overwatered in the beginning and too often, I think I'm doing a lot better now

Due to these problems being present for a while now I have lost my rhythm in terms of feeding every second time only

Like I said above, I have just flushed all three plants properly with plain pH water but I'm not sure what steps to take next

[FlyingDutchPaddy]

hey

i'm aware of that nutrient line - its available where i do my shopping...
what supprises me is that i can't find any indication as to its NPK values, only feeding schedules.

https://www.biobizz.com/wp-content/uploads/2019/10/Data-Sheet-EN-Bio%c2%b7Grow.pdf

https://www.biobizz.com/wp-content/uploads/2020/01/Nutrient-Schedule-EN-2020.pdf

using 0.5ml/L on recommended 1 - 2 ml/L
at best, 50% strength for 'their (BB)' substrate, at worst 25% strength of recommended for coco.

i think you're underfeeding...
what happens if you were to up the dose to 1.25ml/L and let that go for a week?
calmag is fine, keep it there.
in proportion to the new amount of Grow it's contribution to the overal amount of N, howevermuch that is, becomes a lot smaller.

[PaulV]

I'm using canna coco professional pro soil, that's not the pressed brick version. I haven't done any pre prep just mixed it with 30% perlite

[FlyingDutchPaddy]

looks nice..
to quote them: ..." has had a full buffering, eliminating the side effects of growing on coir, as coir could consume some of the nutrients."....

in which case i think it's as it is as i wrote about above.
in my opinion, feeding 0.5ml/L where recommended is 1-2ml/L, is too little.

[PaulV]

NPK is 4-3-6
I will start feeding one of them as u suggested, let's see what happens, would u still water plain pH every other time?
I will also water one of the WW with plain pH only, just to eliminate the possibility of other problems.
In your opinion, how long should it take ideally for growth to improve and or symptoms to stop spreading? About a week?

Thank you guys, so far very helpful 👍

[D.A.A.S.69]

I agree with FDPaddy, they need more feed.
Overwatering young plants, will seriously stunt there growth, an cause problems.
I hope you get them doing right.
Where did you get your seeds?

[PaulV]

Got them from seedsman, so that shouldn't be the issue, like u guys said, I assume it's a combination of problems all started with me being over protective and over watering them, possibly causing root or pH issues plus not feeding enough.....

I've got one more WW seedling growing, hopefully with better watering and more feeed I should not run into the same problem again

I will definitely keep you posted

[PaulV]

Quick update as promised, I've increased feed as suggested but they got burnt immediately, so I was back to square one. I did some deeper research into coir pre buffering and came across a coco pro who was really helpful. Looks like my coir, which according to manufacturer was pre washed and pre buffered, was not ready to be used as promised by manufacturer..... So after all these weeks of seriously doubting myself and almost giving up on my babes I made a ballsy move, got them out of the coco, removed as much as possible and moved them into peat compost+perlite. And guess what? After 5 days of transplant shock they literally exploded, healthy growth, no further deficiencies at all....

Anyways, looks like that coco was pretty shitty so won't be buying again. General advice I got is to buy bricks, soak wash and buffer them yourself to avoid dramas like in my case..... Whish I had known before.

[FlyingDutchPaddy]

happy to hear they bounced back after transplant