Ok, so it's slowly getting thicker and frostier. At week seven my girl could be ready in anywhere from two weeks to four weeks more.
The light was dropped closer to the top of the canopy. I decided to try 15 cm of distance, as well four 50W LEDs are not as powerful as the 600W HID or LED panels that are usually used in grow tents. I will of course keep an eye for signs of light and heat stress, but I suspect that won't be a problem.
Update Day 89.
Today I decided to turn the plant around to see the back colas and their growth. Then I found some mites under the leaves after examining weird spots in a couple of leaves. It seems to me that there was not enough airflow to deter the mites from making home in the back leaves, when compared to the front leaves of my plant. Lesson learnt, rotate plant often, ensure good and even airflow.
I didn't find any webs beside a really small one seen on the video (most affected leaf). So, I think I found them mites early. I only found this kind of damage on very few leaves, and each leave contained less than 8 mites (at least that I could see) and a couple of eggs. So it seems that paying close attention to my leaves saved me from an out of control infestation.
Anyhow... I removed all of the leaves that had even a single mite, or a single mark of discoloration.
Also, I disinfected the grow tent, top of soil and lower part of the branches by spraying them with a 1/4 tbsp of bleach per liter of water.
After that was completely dry, I mixed one part rubbing alcohol with 9 parts water and misted both sides of the leaves and even the buds directly (ethanol evaporates easily, so there shouldn't be residues left after it dries completely).
I got these remedies from https://www.growweedeasy.com/cannabis-plant-problems/how-to-get-rid-of-spider-mites
I will apply them every 3-4 days and keep a good eye on the leaves.
Prevention is key, and some aspects I could've considered before are:
1. not grow any other plant next to my cannabis
2. Don't come into my indoor growtent after tending my outdoor plants.
3. Ensure even and plenty airflow.
So, I attacked back strongly. I cut more leaves than those that showed damage, to increase airflow. I will be on the watch for pests and will rotate my plant often, as well as spraying a few times every week, just to make sure they don't come back.
I also am going to build a kind of metal wire cage to separate the colas further and make it harder for any pest to spread.
Its only my second grow, but from what I've read online about mites, it's way more costly (time and money) to deal with an infestation than to strike them hard early. I guess that specially now that I noticed them before they even made webs.
Look closely at your girls growbros !
Update day 90.
So this morning I. Becker the trichomes and they seem to have gotten more cloudy. I am not an expert at that, but they are starting to be fewer clear and more milky. I will keep an eye on them, but it think harvest might be here very soon, probably closer to the 9 week mark than to the 12 week one (I'm about to finish the 7th week)...