I require aid diagnosing my Northern Light plants

[nadmocni]

Hey guys!

First of all, I hope my English is understandable, it's my second language.
So I've planted my 2 Northern Light plants in the beginning of March and there appear to be some problems with them. I might be a little late trying to solve these issues but I've been very short on time lately + I'm growing just for fun. It's my second grow (I bought three seeds from Amsterdam, planted one last year and the remaining two this year). Last year's plant had similar issues.
About a month ago, some problems started showing up, as seen in pictures. Leaves photographed are brittle and some bottom leaves have started to turn yellow. What might be the cause of this problem and how do I solve it?

Strain - Northern Light
# of Plants - 2
Grow Type - Soil
Grow Stage - Flowering, probably. I was hoping you could tell me that.
Bucket Size - 30 litres
Lights - Sun
Watering - Once every 2 days
Nutrients - NPK for now, I also have some superbloom thing that I haven't used yet. When should I?
Temperature - 25°C during the day and about 15°C during the night
Pests - Some leaf miners (pretty much taken care of) and some green aphids I believe. I've made some stinging nettle spray, it works quite well.

Plant no. 1:

Plant no. 2:
This one hasn't been growing as well as the first one since the beginning.

I hope I've provided enough information for you to help me make the most out of my grow this year. I can provide you with more photos if necessary. Thank you in advance.

PS: I intend to keep things as natural as possible.

Take care,
nadmocni

 

[Dusty Kiefers]

Looks like spider mite damage, and maybe some root bound issues.

 

[iwltfum]

I think it's spider mites too. They can dehydrate and really damage your plant very quickly if there are enough of them.

 

[vastok]

Regular application of neem oil will hold the bugs at bay, but bugs only attack weak plants anyways, so clean her up, by a neem spray 1x times per day also to hold backs any close mold attacks, protect her roots by having the pot on some wood blacks, from the tile heat, avoid any npk, as you don't need the (N) now shes in early bud, as the suns past the solstice, good luck

ps next grow add some perlite like 20-30% is good, to avoid nute burn and root compaction

 

[iwltfum]

Make sure you spray any other plants on that patio when you spray the ladies. If there are any on those other plants, you don't want them to be able to easily migrate to your newly bug-less, and happy plants.

 

[nadmocni]

Thank you so much guys, going to the store to buy some neem oil/spray today!