fungus or deficit?

Hi there fellow growers! This is my 9th indoor grow and for the first time I am facing a problem I cant solve. I have four F1 females in four different pots with the same compost. (The same I have been using since my first grow).
After 20 days in VEG, the leaves started turning yellow. The next stage started with the leaves turning brown, which later translated into necrosis; the leaves twisting and drying around the brown spots. This can be seen clearly in the photo.

I want to highlight the fact that I have always grown my MJ in the same grow room, using the same compost for soil. This is why I am so bewildered, as I cannot solve this issue.
Initially, I got the feeling the plant was lacking nitrogen (As the leaves turning yellow around the edges usually mean that). I applied the usual fertilizer for nutrients in VEG. It seems like the process has been hindered but goes on. It may be that they are lacking nitrogen, but there MUST be something else wrong. From my research on the internet, I understand this is probably a defficiency. However, I fear there may be a fungus infection or something else.

I know from my personal experience that here at rollitup there are plenty of experts who can help.
Please do so.

I hope the pictures are useful.View attachment 2260682View attachment 2260683View attachment 2260684View attachment 2260685

looks to me like a fungus gnat issue. i am going through it as we speak, them shits are all around my yard and i left window open and now their in the house and in my grow area.

at first i thought i was having deficiencies or lock outs, but when i checked my runoff everything was good. i couldn't figure it out for shit but then i saw a couple of gnats flying around a couple days later and thought to myself this has got to be the problem. at the time i didn't know what they were, never had any bugs issues prior to now, but i caught one, researched on the net and found out they were fungus gnats.

luckily i have some of caps' bennies and some fly strips on hand to combat the issue, because they were doing some damage. most of the damage was on the lowers and a little on the top.

Hi there! Here are some pix of the girls. The first two big plants are showing twisted leaves at the top of the plant. The one in the back on the left is actually the first one to ever show these symptoms.
Some leaves are showing necrosis I guess... but the new stems do not seem to have a problem. The problem is with the twisted leaves which are curled.
The problem is not visible in the whole of the plant, just on the middle leaves. I have looked for gnats or other bugs but nothing...
Oh I would like to add that it is WINTER here.. with temperatures below 0° C (water freezing point). What I am doing is keepin the lights on during the coldest hours so the temperature inside the closet stays round 26 and 29°C.
Thanks a ton!


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as i stated before, im having the same issue and the only thing i can come up with is the gnats i've seen. i checked the root ball and foliage with 30x mag. and 100x scope and i don't see any bugs besides the few i've seen flying around. im going to post pics on another site to see what others can come up with and ill let you know what the general consensus is. until then i am going to hit them with some more bennies and see how that works out.

damn just looked at your pics and it looks like it could be a lock out of something, check your runoff and see what it's reading to determine if somethings locked out or deficient. sometimes the twisted leaf indicates a ph issue as well.

ive never seen leaf damage from fungus gnats

you look like your plants need watered more often - they look dry to me
also splotchy leaf fade with necrosis like you have would be indicative of a micro/phosphorous problem to me
this is commonly caused by too low a ph or too high nitrogen content in soil

also when i had very low temps i had all sorts of shock type reactions - foliar feeding a light nute always helped

look at your new growth and compare it to those fans
is your growth slowed or just funky?

it's hard to tell really - if it's a new strain they could just be too sensitive for your grow area

if low temps are a constant issue, try some auto flower genetics - something indica heavy
ruderalis frows on russian steppes - cold
indica grows on mountain sides - cold

idk - stoned ramblings

The grow is just funky. The plants have been in VEG for 40 days and just recently they've started showing these symptoms. Just as I transplanted from 3 L to 15 L pots. In these 15 L pots, they should be starting flowering. So, the percentage of worm humus, which is high in nitro, is very low (around 10%). This is why I rule out an over feeding of N. Nonetheless, I applied a bit of fertilizer for VEG just in case the plants needed more. I believe it is more likely to be a defficiency of N rather than an over feeding.
The varities I have this time are

2 Skunk Sensi Seeds. one presents these problems the other seems fine

1 Sweet Thai - Sweet Seeds. The one with bigger leaves on the pictures, doesnt have necrosis, just a slight yellowing in the edge of the leaves.

1 Sweet Afghani Delicios - Sweet Seeds. Necrosis on the three older leaves so far.


I have grown all these varieties in the winter before and had had great results and yield with the same HPS and growing conditions.

Although the pot is extremely wet after watering it, the plant seems to be dry. It looks sort of fallen... as if it were going through a draught.

I watered them two days ago. The temperature outside the grow room has not reached 10 ° C. The soil takes a long time to dry up, unlike in the summer. I am afraid if I continue to water them the roots may rot. I dont want to spoil the roots basically...
I do appreciate your feedback...

Necrosis like that speaks to me of Ca or K deficiency. I admit it's a long shot. cn

yeah i was going to suggest k deficiency or lock out, from the look of the purpling of the leaves. here's a link to help you out http://www.420magazine.com/forums/problems-pests-disease-control/81275-cannabis-plant-pest-problem-solver-pictorial.html

look under Potassium (K) and Molybdenum (Mo) in the link i just posted.