Bro, it's hard for her to flower in such a lighting schedule of 20/4! This is not an autoflower!!! You should at least set it to 16/8 to double the night during flowering compared to veg! Set it to 12/12 and wait for the growth! Your plant's vertical growth should stop in the 3rd to 4th week of flowering! Remove the lower buds that are very, very weak and practically not illuminated!!! Let the plant direct all its energy to ripening and growing in the areas where it is well lit!!! 👆
Effective lighting ranges, starting from planting the plant:
Day 1 (250-500lux)
Day 2 (500-1000lux)
Day 3 (1000-2000lux)
After five pairs of leaves, full vegetation (2000-20000lux)
Flowering (20000-100000lux). Try not to exceed 99000 lux. Otherwise - problems!
It's easy to check the lighting! 👌
Install a free app called "luxmeter" from the market on your smartphone, clean your phone screen well, removing grease and dirt. The light sensor is located on the screen part, which often rivals individual lux meters. Check the lighting above the plant. Adjust the lamp height so that it doesn't heat the plant to shock states, but stays within the lux range. Install the app, and you'll remember me more than once, bro! It will be like a compass for your lighting! 👌
Good luck, my friend! ✊😇