I did start put a little bit of colloïdal silver ...

Complete honesty, I’ve never used colidal silver before personally. But from what I’ve read you can spray a specific part of the plant to force that part to flip to make and start producing pollen without affecting the rest of the plant. I read it takes several weeks for the plant to switch to producing pollen and colidal silver needs to be applied daily until it flips. Also strong warnings about not smoking any part of the plant that was exposed to colidal silver. Good luck!