Leaves edges curling under

Hey guys
Im totally new to this forum, and i need some help.
This is my 1st "serious" grow, im only done one a few years ago in a little box 1 plant.

Im growing an autoflower strain from Dutch Passion called AutoXtreme.
They are under a 600W HPS bulb and in soil. We are at the 28th day from seed.
my temps min/max about 20/27C or 68/80F.

Im only using 2 fertilizer plagron plagron vita race leaf fertilizer and alga bloom in the water.

2 days ago i noticed that the leaf edges are curling down and into themself, it happens only the highest leaves and the tips curling down a bit too.
what can be the source of the problem?


Sadly i couldnt get a ph meter so far, but i will buy one tomorrow.

Please share your thoughts. I hope my english is understandable enough.
Thanks for any help!

Coldfusion

looking at the slight burn on the tips and leaf canooing i would say over fed!, maybe feed then water then feed etc

i thought about over fert but they got only a half dose alga bloom which i dont think is too much coz they got nothing more, but the curlin is happend later. BTW in the last 2 days the got only pure water.
or maybe i over did a little with the foliar feed. at my native forum a member said its maybe hot stress, but i really dont know

when you over fert plants take time to adjust espesh in soil, so you might correct the problem but wont see signs of improvements untill 4-7 days latter imo.

try and keep temps a constant 72 in flowering if possible to raise yours a touch.

how far is your light away, can you move it closer a touch, if temps are a touch cooler??

p.s sorry for constant repeat of the word touch!

at the moment i raised my lamp to about 40-50cm from the highest plant, before that it was ~30cm.
tha tallest plant is 58cm, max height of the lamp is ~185cm.honestly my temps maxing about 75F in the last few week cold spring in europe but for the 1st time im grateful for it )

move your light back down to 30 cm.

raise plants that are smaller so all plants are the same height giving you an even canopy, making sure your using all your light.

you may be able to get your lamp closer place your head directly over the plants if the light hitting the side of your face hurts raise it and inch and try again if not, see how close you can get it!!

then im back to 30, actually when i saw the cited problem i immediately went on the forum and some guys said hps should be at lest 40-50cm and so i got worried and qiuckly raised the lamp despite that it hasnt been a problem before.

have you checked your ph? could be locking out some of your nutes. try and get it to 6.5 ish

also what kind of soil are you using?

im using plagron royalmix from seed, and about 10 days ago the girls got replanted in 11litre pots. ph meter is a first thing to buy tomorrow.
can it maybe from the soil itself? coz its a fertilized soil and the last week i raised the water ammount to 1l/day

Yeah that could be the issue. since there is time ferts in the soil you may still be over feeding. id give it a good flush