Is this heat stress or nutrient problem?

[Gshoo]

Being inexperienced grower is not an easy thing, especially when you see all sorts of issues that you don’t understand. At least it’s interesting
So guys is this what you see seems familiar to anyone? The plant is Blueberry auto, 2+ weeks old, outdoors in peat, sphagnum moss perlite mix. The story is that I LST 4 days ago and the first two leaves that immediately went yellow were the ones in the bottom. Then yesterday I saw these brown spots on the next level of leaves. Is this sunburn? The past few days the temperature outside has been around 28C, and humidity around 50%, also it was windy. The plant stays all day under the sun. That’s one of my propositions.
The other one is nutrient problem. So The first week I fed the plant with Root Juice + Alga Mic + Acti Vera (Bio Bizz). The brand says that the first week I can give root juice and acti vera, but I think that adding alga mic to the cocktail doesn’t do any harm. Two days ago, I stopped with the root juice and added fish mix to the other two ingredients + cal-mag, the water is 6.5ph.
So please let me know if this seems familiar to you guys or recognize any mistake. The tip of the leaf went missing today, it was alright this morning, maybe the wind.
Thanks

 

[Emilya Green]

I don't see heat stress, but I see signs of overwatering by watering too often and then hiding that damage by snipping off the ends of at least one leaf. You should let your plant dry out all the way to the bottom and so that it is light as a feather, before you water again. Outside that might be every day, but it is important to establish a wet/dry cycle and be able to get oxygen deep down in the soil to those bottom roots. While in veg you need to be quite stingy with the water and force the roots to get stronger as a result. When this plant starts to bloom you will be glad that you have all those strong healthy roots.
Next, in a fast growing auto plant the roots are probably already running out of room in that small container. I would consider uppotting this plant to its final container ASAP.

 

[Gshoo]

I don't see heat stress, but I see signs of overwatering by watering too often and then hiding that damage by snipping off the ends of at least one leaf. You should let your plant dry out all the way to the bottom and so that it is light as a feather, before you water again. Outside that might be every day, but it is important to establish a wet/dry cycle and be able to get oxygen deep down in the soil to those bottom roots. While in veg you need to be quite stingy with the water and force the roots to get stronger as a result. When this plant starts to bloom you will be glad that you have all those strong healthy roots.
Next, in a fast growing auto plant the roots are probably already running out of room in that small container. I would consider uppotting this plant to its final container ASAP.

Oh wow that was the last thing that went through my mind. I thought that I left it to dry properly before watering, the pot was very light. And that was the second proper watering, before I was only spraying. The tip of the leaf was there and it looked healthy and I thought that the wind helped with the damage, today was very windy. I was about to leave the plant one more week in the container. Different plant that I potted in it’s big container after only 1 week had some issues with its development and stayed very small till the end. I thought that I did a mistake then. Thanks for the advices, I’m going to repot. Shall I water straight after I put it in the big pot, this might cause more damage?

 

[Gshoo]

HI @Emilya, sorry to bother, but I want to ask you if this looks like the right time to repot? Now it’s in the final pot, hope this is big enough.
Thanks in advance