Thick main branch but the others dont develop. Any sugestions?

Hi mate, I started my growing passion with outdoor and it was an awakening experience. Looking at your diaries there are a few factors that would cause the issues you are having. Your daytime temperatures are ok but on the very low end of viability. Same goes for your night temperatures. Far too cold to be productive. Every day is goes dormant and then has to recover, everyday. It is an immense amount of stress. Basically the plant is having its own Groundhog Day. VPD is very important, if not the most important. 90% humidity at those temperatures is asking for trouble. You want a steady 50% throughout growth, 60% during germination and seedling stages. Both those levels work for a range of temperatures from 18 - 26'C. Small roots, small plant. Growing outdoors will require more time in the sun than indoors. Therefore it needs a larger space for roots to grow. Minimum 50 Ltr pots for outdoor plants. It give plenty of time for you to solve problems and for her to grow into a lucious plant. I was winging it when I did my outdoor grows. I ultimately lost it all to bud rot due to high humidity at night after a long wet period. They were grown in a plastic greenhouse. Great way to keep those temps up at night and control the humidity a little. The will drink more and eat more than indoor plants in my experience. The best thing about it is you're not restricted by space and can train her any way you want. I hope this helps, god luck and happy growing